02414nas a2200229 4500008004100000022001400041245009500055210006900150260002900219300001400248490000800262520170700270653002701977653001502004653001802019653001302037653001402050100002302064700002102087700002102108856005502129 2012 eng d a1439-043400aDefining plant resistance to Phytophthora cinnamomi: a standardized approach to assessment0 aDefining plant resistance to Phytophthora cinnamomi a standardiz bBlackwell Publishing Ltd a269–2760 v1603 a

Phytophthora cinnamomi is a soil-borne plant pathogen that causes devastating disease in agricultural and natural systems worldwide. While a small number of species survive infection by the pathogen without producing disease symptoms, the nature of resistance, especially under controlled conditions, remains poorly understood. At present, there are no standardized criteria by which resistance or susceptibility to P. cinnamomi can be assessed, and we have used five parameters consisting of plant fresh weight, root growth, lesion length, relative chlorophyll content of leaves and pathogen colonization of roots to analyse responses to the pathogen. The parameters were tested using two plant species, Zea mays and Lupinus angustifolius, through a time course study of the interactions and resistance and susceptibility defined 7 days after inoculation. A scoring system was devised to enable differentiation of these responses. In the resistant interaction with Z. mays, there was no significant difference in fresh weight, root length and relative chlorophyll content in inoculated compared with control plants. Both lesion size and pathogen colonization of root tissues were limited to the site of inoculation. Following inoculation L. angustifolius showed a significant reduction in plant fresh weight and relative leaf chlorophyll content, cessation of root growth and increased lesion lengths and pathogen colonization. We propose that this technique provides a standardized method for plant–P. cinnamomi interactions that could be widely used to differentiate resistant from susceptible species.

10aPhytophthora cinnamomi10aresistance10aroot pathogen10aZea mays10azoospores1 aAllardyce, Jane, A1 aRookes, James, E1 aCahill, David, M uhttp://dx.doi.org/10.1111/j.1439-0434.2012.01895.x01942nas a2200145 4500008004100000022001400041245016600055210006900221260001600290300002000306520136300326100001701689700002001706856007001726 2018 eng d a0031-949X00aDistinct Trophic Specializations Affect How Phytophthora ramorum and Clade 6 Phytophthora spp. Colonize and Persist on Umbellularia californica Leaves in Streams0 aDistinct Trophic Specializations Affect How Phytophthora ramorum cJun-05-2018 aPHYTO-06-17-0193 a

Phytophthora spp. are regularly recovered from streams but their ecology in aquatic environments is not well understood. Phytophthora ramorum, invasive in California forests, persists in streams at times when sporulation in the canopy is absent, suggesting that it reproduces in the water. Streams are also inhabited by resident, clade 6 Phytophthora spp., believed to be primarily saprotrophic. We conducted experiments to determine whether differences of trophic specialization exist between these two taxa, and investigated how this may affect their survival and competition on stream leaf litter. P. ramorum effectively colonized fresh (live) rhododendron leaves but not those killed by freezing or drying, whereas clade 6 species colonized all leaf types. However, both taxa were recovered from naturally occurring California bay leaf litter in streams. In stream experiments, P. ramorum colonized bay leaves rapidly at the onset; however, colonization was quickly succeeded by clade 6 species. Nevertheless, both taxa persisted in leaves over 16 weeks. Our results confirm that clade 6 Phytophthora spp. are competent saprotrophs and, though P. ramorum could not colonize dead tissue, early colonization of suitable litter allowed it to survive at a low level in decomposing leaves.

1 aAram, Kamyar1 aRizzo, David, M uhttps://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-06-17-0196-R02019nas a2200169 4500008004100000022001300041245008200054210006900136260001100205520150300216100001601719700001201735700001701747700001501764700002101779856004901800 2013 eng d a1618866700aA diverse range of Phytophthora species are associated with dying urban trees0 adiverse range of Phytophthora species are associated with dying  c9/20133 a

Surveys of dying vegetation within remnant bushland, parks and gardens, and streetscapes throughout the urban forest of Perth and the South-west of Western Australia revealed symptoms typical of those produced by Phytophthora species. A total of nine Phytophthora species, including P. alticola, P. multivora, P. litoralis, P. inundata, P. nicotianae and P. palmivora were isolated. In addition, three previously undescribed species, Phytophthora aff. arenaria, Phytophthora aff. humicola and Phytophthora sp. ohioensis were isolated. Isolates were recovered from a wide range of native and non-native host genera, including Agonis, Allocasuarina, Brachychiton, Calothamnus, Casuarina, Corymbia, Dracaena, Eucalyptus, Ficus, Pyrus and Xanthorrhoea. Phytophthora multivora was the most commonly isolated species. Out of 230 samples collected 69 were found to be infected with Phytophthora. Of those 69, 54% were located within parks and gardens, 36% within remnant bushland, and 10% within streetscapes. These pathogens may play a key role in the premature decline in health of the urban forest throughout Perth, and should be managed according to the precautionary principle and given high priority when considering future sustainable management strategies.

1 aBarber, P A1 aPaap, T1 aBurgess, T I1 aDunstan, W1 aHardy, G.E.St.J. uhttp://dx.doi.org/10.1016/j.ufug.2013.07.00902117nas a2200193 4500008004100000022001400041245009800055210006900153260001600222300001400238490000800252520150500260100002201765700001601787700002201803700001801825700001501843856006501858 2016 eng d a0191-291700aDetection of Phytophthora ramorum in Nurseries and Forest Lands in California in 2004 to 20090 aDetection of Phytophthora ramorum in Nurseries and Forest Lands  cJan-01-2016 a139 - 1480 v1003 a

From December 2004 through May 2009, samples were collected from California nurseries and wild lands to survey for Phytophthora ramorum and comply with federal regulations of nursery stock. Samples were prescreened by an enzyme-linked immunosorbent assay (ELISA) that detects Phytophthora spp. and tested by culture, P. ramorum-specific real-time polymerase chain reaction (PCR), and nested PCR. Yearly percentages of infected samples ranged from 0.6 to 2.3%. Camellia spp., Rhododendron spp., Magnolia spp., Pieris spp., and Laurus nobilis tested positive the most frequently in the nurseries and Lithocarpus densiflorus, Umbellularia californica, and Quercus agrifolia tested positive most often from wild lands. Of the 118,410 samples isolated onto PARP media, 0.8% was identified as P. ramorum. Of 115,056 samples tested by ELISA, 5.9% tested positive for Phytophthora spp. Of the 6,520 samples tested by PCR, 12.4% tested positive for P. ramorum. The false-negative, positive, and internal control failure rates of the assays are discussed. After removing the seasonal effect of sampling strategy, isolation of the pathogen into culture was found to be seasonally dependent whereas detectability by PCR and ELISA was not. To our knowledge, this is the first evaluation of a regulatory testing program for a plant pathogen on this scale using standardized assays.

1 aBlomquist, C., L.1 aYakabe, L E1 aRooney-Latham, S.1 aMcRoberts, N.1 aThomas, C. uhttp://apsjournals.apsnet.org/doi/10.1094/PDIS-12-14-1302-RE00519nas a2200145 4500008004100000245007000041210006600111260001300177100001900190700001800209700001300227700001600240700001400256856010300270 2007 eng d00aA disease survey of cherimoya orchards in Northland, New Zealand.0 adisease survey of cherimoya orchards in Northland New Zealand aAdelaide1 aBraithwaite, M1 aBullians, M S1 aPay, J M1 aGill, G S C1 aHill, C F uhttps://forestphytophthoras.org/references/disease-survey-cherimoya-orchards-northland-new-zealand02843nas a2200193 4500008004100000245015000041210006900191260001600260300000800276490000700284520217800291100001902469700002302488700002002511700001802531700002202549700003002571856004802601 2020 eng d00aDiversity and Pathogenicity of Phytophthora Species Associated with Declining Alder Trees in Italy and Description of Phytophthora alpina sp. nov0 aDiversity and Pathogenicity of Phytophthora Species Associated w cAug-05-2020 a8480 v113 a

Extensive decline and mortality events of alder trees have recently been observed in several riparian ecosystems in Italy. Since there is little information about the aetiology of this disease and given the high ecological relevance of riparian ecosystems, an in-depth study was conducted in three sites spanning from the Mediterranean to Alpine regions. From spring 2019 to spring 2020, 261 samples of bleeding cankers, rhizosphere soil and leaves used as baits along waterways were collected and used for Phytophthora isolation. Based on morphology, colony appearance and DNA sequence data, 10 species belonging to 6 clades were identified. These included P. plurivora (84 isolates), P. pseudocryptogea (50), P. hydropathica (18), P. gonapodyides (14), P. bilorbang (13), P. pseudosyringae (12), P. lacustris (11), P. acerina (7), P. cactorum (1) and one isolate of the hybrid Phytophthora ×serendipita. In addition, two new Phytophthora species, one of which is described here as Phytophthora alpina sp. nov., were isolated. The pathogenicity of P. alpina and other species obtained from samples collected in the green alder stand was assessed on 3-year-old seedlings. All species proved to be pathogenic on green alder causing symptoms congruent with field observations. Results obtained have allowed us to expand knowledge about alder decline aetiology. The diversity of pathogenicity of Phytophthora species associated with symptomatic alder trees suggested that no single agent is responsible for the disease, but that it is the result of multiple infections of different Phytophthora species, variable in assemblages among sites.

1 aBregant, Carlo1 aSanna, Gian, Paolo1 aBottos, Adriano1 aMaddau, Lucia1 aMontecchio, Lucio1 aLinaldeddu, Benedetto, T. uhttps://www.mdpi.com/1999-4907/11/8/848/htm01112nas a2200193 4500008004100000022001400041245009800055210006900153300000600222490001300228520050000241100002400741700001700765700001500782700001800797700001600815700001600831856007100847 2012 eng d a1130-140600aDeveloping a taxonomic identification system of Phytophthora species based on microsatellites0 aDeveloping a taxonomic identification system of Phytophthora spe a-0 vIn press3 a

Phytophthora spp. is the most important genus of the Oomycete plant pathogens. Nowadays, there are 117 described species in this genus, most of them being primary invaders of plant tissues. The different species are causal agents of diseases in a wide range of crops and plants in natural environments. In order to develop control strategies against Phytophthora spp., it is important to know the biology, ecology and evolutionary processes of these important pathogens.

1 aCastillo-Múnera, J1 aCárdenas, M1 aPinzón, A1 aCastañeda, A1 aBernal, A J1 aRestrepo, S uhttp://www.sciencedirect.com/science/article/pii/S113014061200110602430nas a2200169 4500008004100000022001400041245010400055210006900159260002900228300001200257490000700269520187700276100001602153700001802169700001802187856005502205 2012 eng d a1439-032900aDetection of mRNA by reverse-transcription PCR as an indicator of viability in Phytophthora ramorum0 aDetection of mRNA by reversetranscription PCR as an indicator of bBlackwell Publishing Ltd a14–210 v423 a

In the last few decades, the use of molecular tools has greatly improved the efficiency of plant disease diagnosis. However, one of the major setbacks of most molecular diagnostic approaches is their inability to differentiate between dead and viable pathogens. We propose a new strategy for the detection of plant pathogens, based on the use of mRNA as a viability marker, on the basis that mRNA degradation in dead cells is significantly more rapid than that of DNA. A real-time reverse-transcription PCR (RT-PCR) assay targeting the mRNA of the subunit I of the cytochrome oxidase gene was designed for Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight. In controlled laboratory tests, the developed RT-PCR assay did not detect the target mRNA a week after the pathogen had been killed by rapid lyophilization, while DNA of the pathogen could still be detected 3 months after the pathogen had died. The RT-PCR assay was then compared with a traditional culturing approach using PARP selective medium and two nested real-time PCR techniques on symptomatic California bay laurel leaves. Samples were either collected in three different sites in July, or in the same site but in three different seasons. Overall, RT-PCR results showed less positive samples than DNA-based nested PCR techniques (p < 0.0001), but more than culturing (p = 0.017). Nested PCR-positive but RT-PCR-negative samples may not be viable. On the other hand, RT-PCR-positive but culture-negative samples may be viable but dormant. A comparative analysis of the results indicated that RT-PCR and culturing provide comparable results when climatic conditions are optimal for the pathogen, but RT-PCR may be the most accurate approach to determine pathogen viability when climatic conditions are less than optimal for the pathogen.

1 aChimento, A1 aCacciola, S O1 aGarbelotto, M uhttp://dx.doi.org/10.1111/j.1439-0329.2011.00717.x01889nas a2200313 4500008004100000245010900041210006900150300001200219490000700231520093800238653002301176653002301199653001901222653001601241653002101257653002901278653002101307653001001328653001201338653002001350653001601370653002601386653003501412653001801447653002601465653001001491100001801501856005601519 1950 eng d00aThe distribution and significance of the chestnut root rot Phytophthoras, P. cinnamomi and P. cambivora.0 adistribution and significance of the chestnut root rot Phytophth a194–60 v343 a

A review of literature, with special reference to some recent publications in Spain and Portugal [cf. For. Abstr. 11 (Nos. 1468, 2268)]. The author concludes that Phytophthora cinnamomi plays a great part in disease of Chestnut in Spain, Portugal, France and Italy, and elsewhere in southern Europe, and is probably the major cause of death in the more southerly regions. P. cinnamomi has a considerable range of hosts. It has been found to attack Castanea sativa, Juglans regia, Pseudotsuga taxifolia, Quercus robur, Q. suber, Betula alba, Cedrus atlantica, Abies nordmanniana, A. alba, A. sibirica and Castanea crenata var. tamba. A close watch on Douglas Fir in the U.S.A. seems advisable in case a strain of the fungus should encounter and attack it. In contrast P. cambivora has only been found on Castanea sativa and C. crenata var. tamba.

10aAbies alba disease10aAbies nordmanniana10aAbies sibirica10aBetula alba10aCastanea crenata10aCastanea sativa diseases10aCedrus atlantica10adecay10aDisease10afungal diseases10aInk disease10aJuglans regia disease10aPseudotsuga laxifolia diseases10aQuercus robur10aQuercus suber disease10atrees1 aCrandall, B S uhttp://www.cabdirect.org/abstracts/19500602345.html02221nas a2200241 4500008004100000245009100041210006900132300001100201490000800212520145200220653001801672653001401690653001801704653002101722100001901743700002201762700002401784700002101808700001801829700002501847700002601872856008101898 2009 eng d00aDNA-based method for rapid identification of the pine pathogen, Phytophthora pinifolia0 aDNAbased method for rapid identification of the pine pathogen Ph a99-1040 v2983 a

Phytophthora pinifolia causes a needle and shoot disease in Pinus radiata, referred to as ‘Daño Foliar del Pino’. This newly discovered disease requires intensive research efforts that necessitate the processing of large numbers of samples for which accurate identification, often by people not experienced in Phytophthora taxonomy, is required. The aim of this study was, therefore, to develop species-specific primers for P. pinifolia that amplify the internal transcribed spacer region of the ribosomal operon and the nuclear Ypt1 gene, respectively. The primers were tested over several Phytophthora spp., as well as fungi isolated from P. radiata. In all cases, only P. pinifolia was amplified. In addition to the species-specific primers, a PCR-restriction fragment length polymorphism protocol using available Phytophthora genus-specific primers was also used to generate a species-specific profile for P. pinifolia. This provided a characteristic profile that allows the identification of P. pinifolia, and it could also discriminate between 27 different species of Phytophthora. Both techniques reported in this study make it possible to identify large numbers of P. pinifolia cultures accurately and efficiently, which will be important for both quarantine work and biological research on this important new pathogen.

10aMonterey pine10aoomycetes10aPinus radiata10atree defoliation1 aDurán, Alvaro1 aSlippers, Bernard1 aGryzenhout, Marieka1 aAhumada, Rodrigo1 aDrenth, Andre1 aWingfield, Brenda, D1 aWingfield, Michael, J uhttp://onlinelibrary.wiley.com/doi/10.1111/j.1574-6968.2009.01700.x/abstract01958nas a2200169 4500008004100000022001400041245012300055210006900178260001200247300001600259490000700275520141000282100001901692700001501711700001201726856005001738 2013 eng d a0191-291700aDevelopment of a Nested Quantitative Real-Time PCR for Detecting Phytophthora cinnamomi in Persea americana Rootstocks0 aDevelopment of a Nested Quantitative RealTime PCR for Detecting  c08/2013 a1012 - 10170 v973 a

Phytophthora cinnamomi causes Phytophthora root rot (PRR) in avocado (Persea americana), an important disease that causes severe economic losses to the avocado industry globally. To date, no PRR-resistant avocado rootstock variety has been discovered, although certain rootstock varieties have been shown to be more tolerant than others. In this study, we developed an accurate, low cost assay for in planta quantification of P. cinnamomi to evaluate disease tolerance. A nested real-time polymerase chain reaction assay was developed to sensitively detect pathogen DNA in plant tissues. Root samples from a highly tolerant (Dusa) and less tolerant (R0.12) rootstock were collected at 0, 3, 7, 14, and 21 days after inoculation with P. cinnamomi and used for pathogen quantification. Nested primers developed in this study were specific and sensitive and could detect P. cinnamomi in root tissues. The amount of P. cinnamomi quantified in roots was significantly higher in the less-tolerant R0.12 plants when compared with the highly tolerant Dusa plants at all time points. This study has confirmed the known status of disease tolerance of Dusa and R0.12 avocado rootstocks in a quantitative manner and provides a reliable molecular tool to assist with industry breeding programs for the selection of PRR-resistant avocado rootstock varieties.

1 aEngelbrecht, J1 aDuong, T A1 aBerg, N uhttp://dx.doi.org/10.1094/PDIS-11-12-1007-RE 02247nas a2200157 4500008004100000022001400041245009700055210006900152260001600221300001200237490000800249520172800257100001701985700001802002856006902020 2015 eng d a0031-949X00aDetection, Diversity, and Population Dynamics of Waterborne Phytophthora ramorum Populations0 aDetection Diversity and Population Dynamics of Waterborne Phytop cJan-01-2015 a57 - 680 v1053 a

Sudden oak death, the tree disease caused by Phytophthora ramorum, has significant environmental and economic impacts on natural forests on the U.S. west coast, plantations in the United Kingdom, and in the worldwide nursery trade. Stream baiting is vital for monitoring and early detection of the pathogen in high-risk areas and is performed routinely; however, little is known about the nature of water-borne P. ramorum populations. Two drainages in an infested California forest were monitored intensively using stream-baiting for 2 years between 2009 and 2011. Pathogen presence was determined both by isolation and polymerase chain reaction (PCR) from symptomatic bait leaves. Isolates were analyzed using simple sequence repeats to study population dynamics and genetic structure through time. Isolation was successful primarily only during spring conditions, while PCR extended the period of pathogen detection to most of the year. Water populations were extremely diverse, and changed between seasons and years. A few abundant genotypes dominated the water during conditions considered optimal for aerial populations, and matched those dominant in aerial populations. Temporal patterns of genotypic diversification and evenness were identical among aerial, soil, and water populations, indicating that all three substrates are part of the same epidemiological cycle, strongly influenced by rainfall and sporulation on leaves. However, there was structuring between substrates, likely arising due to reduced selection pressure in the water. Additionally, water populations showed wholesale mixing of genotypes without the evident spatial autocorrelation present in leaf and soil populations.

1 aEyre, C., A.1 aGarbelotto, M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-07-13-0196-R00502nas a2200133 4500008004100000245012200041210006900163300001400232490000700246100001800253700001500271700001500286856006700301 2007 eng d00aDetection, distribution, sporulation, and survival of Phytophthora ramorum in a California redwood-tanoak forest soil0 aDetection distribution sporulation and survival of Phytophthora  a1366-13750 v971 aFichtner, E J1 aLynch, S C1 aRizzo, D M uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO-97-10-136600358nas a2200097 4500008004100000245005400041210005400095260002700149100003800176856004600214 2006 eng d00aDistribution of the Phytophthora disease of alder0 aDistribution of the Phytophthora disease of alder bUK Forestry Commission1 aForestry_Commission_Great_Britain uhttp://www.forestry.gov.uk/fr/INFD-737J2S03959nas a2200181 4500008004100000245010100041210006900142260001600211300000600227490000700233520336600240100001303606700001703619700002003636700001503656700001503671856009103686 2012 eng d00aDieback and mortality of Juniperus communis in Britain associated with Phytophthora austrocedrae0 aDieback and mortality of Juniperus communis in Britain associate cJul-12-2014 a20 v263 a

In late 2010 reports were received of serious decline of native juniper (Juniperus communis) at the Upper Teesdale National Nature Reserve in northern England comprising more than 200 ha of juniper. Dead and dying juniper trees were scattered throughout an area of approximately 14 ha, mainly concentrated on wet, flat ground but also extending outwards across drier slopes. Affected trees had foliage reddening and browning over all or most of the crown (Figs. 1, 2). Examination of ten trees showing these symptoms revealed orange-brown lesions in the phloem at the stem collar and upper roots (Fig. 3). Scattered dieback of shoots or individual branches (Fig. 4a) was also observed, and three trees examined with these symptoms had discrete girdling orange-brown phloem lesions with no apparent connection to the base of the tree (Fig. 4b). Phloem samples from lesion margins were plated on to SMA + MRP Phytophthora selective medium (Brasier et al., 2005) and incubated at room temperature (15-24°C) in the dark. After transfer to V8 agar, colonies were very slow growing (<0.5 mm per day at 17°C), forming dense, white mycelia (Fig. 5a) with coralloid hyphae (Fig. 5b); amphigynous antheridia measuring 10.8-19.9 µm in diameter (mean 13.2-16.2 µm); and globose oogonia with smooth hyaline to brown walls ranging in diameter between 23.5-41.2 µm (mean 34.4 µm). Semi- and non-papillate sporangia measuring 35.3-58.8 x 23.5-35.3 µm were also observed on V8 agar. Based on the above morphological characteristics and sequencing of the ITS and coxII regions (GenBank Accession Nos. JQ346527 and JQ346528), the isolates were identified as Phytophthora austrocedrae Gresl. & E.M. Hansen, associated with mortality of Austrocedrus chilensis in Argentina (Greslebin et al., 2007; Greslebin & Hansen, 2010). Direct PCR and sequencing of diseased phloem from basal and branch lesions on juniper trees from which no Phytophthora was obtained yielded the same result.

Pathogenicity of the isolate was tested using the method of Greslebin & Hansen (2010) in which the stem bases of six healthy, 30-40 cm high, potted junipers were inoculated with 6 mm diameter mycelial plugs from the margin of a five-week-old P. austrocedrae culture growing on V8 agar. The plants were incubated in a greenhouse at 17°C with natural lighting. Four weeks after inoculation, five of the juniper plants exhibited orange-brown phloem lesions of mean length 49 ± 8 mm extending both up the main stem and down into the root system. P. austrocedrae was successfully re-isolated on to SMA + MRP medium from lesion margins, thereby satisfying Koch’s postulates. Control plants inoculated with sterile agar plugs remained healthy. This is the first finding of P. austrocedrae infecting a Juniperus species worldwide. Although P. austrocedrae is not currently a statutory listed organism within the European Union, biosecurity measures are being applied at the infested site to contain the pathogen. In February 2012 P. austrocedrae was confirmed infecting mature upland juniper at a second site in Britain, located in Perthshire, Scotland. Other juniper sites in Britain with similar decline symptoms are now under investigation.

1 aGreen, S1 aHendry, S.J.1 aMacAskill, G.A.1 aLaue, B.E.1 aSteele, H. uhttp://www.ndrs.org.uk/contents.php?vol=26http://www.ndrs.org.uk/article.php?id=02600202388nas a2200217 4500008004100000022001400041245010900055210006900164260001200233300001200245490000700257520173900264100001302003700001702016700001702033700001702050700001902067700001402086700001502100856005502115 2012 eng d a1439-032900aThe destructive invasive pathogen Phytophthora lateralis found on Chamaecyparis lawsoniana across the UK0 adestructive invasive pathogen Phytophthora lateralis found on Ch c02/2013 a19–280 v433 a

In 2010–2011, Phytophthora lateralis was isolated from diseased Chamaecyparis lawsoniana exhibiting dieback and mortality at eight geographically separate forest, parkland and shelterbelt locations in England, Scotland and Northern Ireland. In 2011, P. lateralis was also isolated from young symptomatic nursery plants of C. lawsoniana and Thuja occidentalis recently imported into Scotland from mainland Europe. These are the first findings of P. lateralis in the UK. At six of the field sites, only collar and root lesions were observed. However, at two sites, large stem and branch lesions unconnected to the collar region were also observed. Phytophthora lateralis was readily isolated from both aerial and basal lesions. In artificial inoculation experiments, two Scottish isolates of the pathogen caused lesions on C. lawsoniana shoots and were readily reisolated from the lesions, their pathogenicity being comparable to that of P. lateralis isolates originating from outside the UK. Isolates from six field sites and the two nursery interceptions exhibited ITS and coxII sequences identical to published sequences of French and North American isolates. However, the isolates from two field sites shared an ITS sequence with Taiwanese isolates and differed from North American, French and Taiwanese isolates by a single-base substitution in coxII, suggesting a separate evolutionary history. It is clear that P. lateralis now presents a significant threat to C. lawsoniana in Britain. The main source of the outbreaks is likely to be imported infested nursery stock.

1 aGreen, S1 aBrasier, C M1 aSchlenzig, A1 aMcCracken, A1 aMacAskill, G A1 aWilson, M1 aWebber, JF uhttp://dx.doi.org/10.1111/j.1439-0329.2012.00788.x00421nas a2200109 4500008004100000245006900041210006600110300001200176490000600188100001400194856010300208 1876 eng d00aDie Buchencotyledonen-Krankheit (The cotyledon disease of beech)0 aDie BuchencotyledonenKrankheit The cotyledon disease of beech a117-1230 v81 aHartig, R uhttps://forestphytophthoras.org/references/die-buchencotyledonen-krankheit-cotyledon-disease-beech00501nas a2200109 4500008004100000245012600041210006900167300001000236490000600246100001400252856012500266 1880 eng d00aDer Buchenkeimlingspilz, Phytophthora (Peronospora fagi M). (The beech seedling fungus Phytophthora (Peronospora fagi M))0 aDer Buchenkeimlingspilz Phytophthora Peronospora fagi M The beec a33-570 v11 aHartig, R uhttps://forestphytophthoras.org/references/der-buchenkeimlingspilz-phytophthora-peronospora-fagi-m-beech-seedling-fungus01860nas a2200157 4500008004100000245013300041210006900174300001400243490000700257520128500264100002501549700001701574700001601591700002301607856007201630 2004 eng d00aDetection and quantification of Phytophthora ramorum from California forests using a real-time polymerase chain reaction assay-00 aDetection and quantification of Phytophthora ramorum from Califo a1075-10830 v943 a

The timely and accurate detection of pathogens is a critical aid in the study of the epidemiology and biology of plant diseases. In the case of regulated organisms, the availability of a sensitive and reliable assay is essential when trying to achieve early detection of the pathogen. We developed and tested a real-time, nested polymerase chain reaction (PCR) assay for the detection of Phytophthora ramorum, causal agent of sudden oak death. This technique then was implemented as part of a widespread environmental screen throughout California. The method here described is sensitive, detecting less than 12 fg of pathogen DNA, and is specific for P. ramorum when tested across 21 Phytophthora spp. Hundreds of symptomatic samples from 33 sites in 14 California counties were assayed, resulting in the discovery of 10 new host species and 23 infested areas, including 4 new counties. With the exception of a single host, PCR-based discovery of new hosts and infested areas always was confirmed by traditional pathogen isolations and inoculation studies. Nonetheless, molecular diagnostics were key in early pathogen detection, and steered the direction of further research on this newly discovered and generalist Phytophthora species.

1 aHayden, Katherine, J1 aRizzo, David1 aTse, Justin1 aGarbelotto, Matteo uhttp://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO.2004.94.10.107503317nas a2200205 4500008004100000245020200041210006900243260001600312300001000328490000700338520256500345100001702910700002202927700002202949700002302971700002302994700002003017700002103037856005303058 2014 eng d00aDecline in vitality of propagules of Phytophthora pluvialis and Phytophthora kernoviae and their inability to contaminate or colonise bark and sapwood in Pinus radiata export log simulation studies0 aDecline in vitality of propagules of Phytophthora pluvialis and  cJan-12-2014 a13 pp0 v443 a

Background: Phytophthora pluvialis Reeser, W.L. Sutton & E.M. Hansen is the cause of a newly described disease, red needle cast, in certain stands of Pinus radiata D. Don in New Zealand that experience periodic foliage browning, while Phytophthora kernoviae Brasier, Beales & Kirk is also infrequently isolated from symptomatic needles.

Methods: Studies were undertaken to test the possibility that these species may be transported on pine logs either as superficial contaminants or as colonists of bark or wood.

Results: Pine-needle baiting found no evidence of Phytophthora species in bark samples or aqueous bark washes from stems of 603 symptomatic trees in 17 affected stands implying that survival after natural deposition of sporangia or zoospores is low or absent. The persistence of zoospores or oospores was evaluated at intervals after applying them at artificially high surface densities to the bark on log segments and incubating at five temperatures between 15°C and 35°C in the laboratory. The ability to re-isolate Phytophthora kernoviae decreased with time and increasing temperature, but this species was s till obtained at low frequencies after 4 weeks at 15°C and 20°C following treatment with oospores of Phytophthora kernoviae. Phytophthora pluvialis could not be isolated under any conditions of time or temperature tested. Percentage vitality of oospores of both species as determined using tetrazolium bromide vital staining also decreased with time, although some oospores of both species remained alive after 4 weeks at all temperatures tested. In a further study to test potential log colonisation, Phytophthora spp. were not isolated from bark or xylem at or near points where zoospores, oospores or mycelium of either species were applied to the bark or sapwood of pine segments and incubated for 6 weeks under ambient or humid conditions at 17°C.

Conclusion: The results of these studies suggest that occurrence of Phytophthora kernoviae or Phytophthora pluvialis on export logs from affected stands is negligible. In addition, although some remained alive, the substantial decline in vitality among artificially applied oospores implies that the survival of any few that may be naturally present on logs is likely to be slight. Based on the evidence from this work there appears to be little risk of transporting these Phytophthora species on New Zealand radiata pine logs.

1 aHood, Ian, A1 aWilliams, Nari, M1 aDick, Margaret, A1 aArhipova, Natalija1 aKimberley, Mark, O1 aScott, Peter, M1 aGardner, Judy, F uhttp://www.nzjforestryscience.com/content/44/1/701962nas a2200265 4500008004100000022001400041245015100055210006900206260002500275300001200300490000800312520109300320653002701413653002701440653001701467653001701484100002301501700002301524700002401547700002101571700001801592700001801610700002001628856004801648 2011 eng d a0929-187300aDevelopment of a real-time PCR assay for detection of Phytophthora kernoviae and comparison of this method with a conventional culturing technique0 aDevelopment of a realtime PCR assay for detection of Phytophthor bSpringer Netherlands a695-7030 v1313 a

Phytophthora kernoviae is a recently described pathogen causing leaf blight, aerial dieback and bleeding cankers on trees and shrubs in parts of Great Britain and Ireland and recently reported in New Zealand. This paper describes the development of a TaqMan real-time PCR assay based on internal transcribed spacer (ITS) sequence to aid diagnosis of this pathogen in culture and in plant material. The assay showed no cross reaction with 29 other Phytophthora species, including the closely related species P. boehmeriae, and detected at least 1.2 pg of P. kernoviae DNA per reaction. A rapid and simple method can be used to extract DNA prior to testing by real-time PCR, and a plant internal control assay can be used to aid interpretation of negative results. A comparison of real-time PCR and plating for 526 plant samples collected in the UK indicated that this assay is suitable for use in routine screening for P. kernoviae.

10aDiagnostic sensitivity10aDiagnostic specificity10aplant health10aRhododendron1 aHughes, KelvinJ.D.1 aTomlinson, JennyA.1 aGiltrap, PatriciaM.1 aBarton, Victoria1 aHobden, Ellie1 aBoonham, Neil1 aLane, CharlesR. uhttp://dx.doi.org/10.1007/s10658-011-9843-x02032nas a2200169 4500008004100000245010500041210006900146300001400215490000700229520147100236100001701707700002401724700002501748700002101773700001701794856005101811 2007 eng d00aDistribution and expression of elicitin genes in the interspecific hybrid oomycete Phytophthora alni0 aDistribution and expression of elicitin genes in the interspecif a5587-55970 v733 a

Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3' untranslated region (3'UTR)-specific PCRs and sequencing. The occurrence of multiple 3'UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species.

1 aIoos, Renaud1 aPanabières, Franck1 aIndustri, Beno{\^ıt1 aAndrieux, Axelle1 aFrey, Pascal uhttp://aem.asm.org/content/73/17/5587.abstract01902nas a2200253 4500008004100000022001400041245007500055210006900130300001600199490000700215520113900222653001401361100001901375700001801394700002101412700002001433700002301453700001901476700002401495700001901519700002001538700001901558856007101577 2011 eng d a0956-566300aDevelopment of a lab-on-a-chip device for diagnosis of plant pathogens0 aDevelopment of a labonachip device for diagnosis of plant pathog a4070 - 40750 v263 a

A lab-on-a-chip system for rapid nucleic acid-based analysis was developed that can be applied for diagnosis of selected Phytophthora species as a first example for use in plant pathology. All necessary polymerase chain reaction process (PCR) and hybridization steps can be performed consecutively within a single chip consisting of two components, an inflexible and a flexible one, with integrated microchannels and microchambers. Data from the microarray is collected from a simple electrical measurement that is based on elementary silver deposition by enzymatical catalyzation. Temperatures in the PCR and in the hybridization zone are managed by two independent Peltier elements. The chip will be integrated in a compact portable system with a pump and power supply for use on site. The specificity of the lab-on-a-chip system could be demonstrated for the tested five Phytophthora species. The two Pythium species gave signals below the threshold. The results of the electrical detection of the microarray correspond to the values obtained with the control method (optical grey scale analysis).

10adetection1 aJulich, Sandra1 aRiedel, Marko1 aKielpinski, Mark1 aUrban, Matthias1 aKretschmer, Robert1 aWagner, Stefan1 aFritzsche, Wolfgang1 aHenkel, Thomas1 aMöller, Robert1 aWerres, Sabine uhttp://www.sciencedirect.com/science/article/pii/S095656631100191602811nas a2200289 4500008004100000245010800041210006900149260001600218300001400234490000700248520193800255100001302193700001802206700001502224700001502239700002102254700001302275700001302288700001302301700001502314700001802329700001302347700001902360700001302379700001602392856011302408 2017 eng d00aDiversity of Phytophthora species in natural ecosystems of Taiwan and association with disease symptoms0 aDiversity of Phytophthora species in natural ecosystems of Taiwa cJan-07-2016 a194–2110 v663 a

In 2013 a survey of Phytophthora diversity was performed in 25 natural and seminatural forest stands and 25 rivers in temperate montane and subtropical lowland regions of Taiwan. Using baiting assays, 10 described species and 17 previously unknown taxa of Phytophthora were isolated from 71.5% of the 144 rhizosphere soil samples from 33 of 40 tree species sampled in 24 forest stands, and from 19 rivers: P. capensis, P. citrophthora, P. plurivora, P. tropicalis, P. citricola VII, P. sp. × botryosa-like, P. sp. × meadii-like and P. sp. occultans-like from Clade 2; P. palmivora from Clade 4; P. castaneae and P. heveae from Clade 5; P. chlamydospora and P. sp. forestsoil-like from Clade 6; P. cinnamomi (Pc), P. parvispora, P. attenuata nom. prov., P. flexuosa nom. prov., P. formosa nom. prov., P. intricata nom. prov., P. × incrassata nom. prov. and P. × heterohybrida nom. prov. from Clade 7; P. sp. palustris and five new hybrid species from Clade 9. The A1 mating type of Pc was widespread in both montane and lowland forests and rarely associated with disease, whereas the A2 mating type was limited to lowland forests and in some cases causing severe dieback. Most other Phytophthora species were not associated with obvious disease symptoms. It is concluded that (i) Taiwan is within the centre of origin of most Phytophthora taxa found, (ii) Pc A2 is an introduced invasive pathogen, and (iii) interspecific hybridizations play a major role in speciation and species radiations in diverse natural ecosystems.

1 aJung, T.1 aChang, T., T.1 aBakonyi, J1 aSeress, D.1 aPérez-Sierra, A1 aYang, X.1 aHong, C.1 aScanu, B1 aFu, C., H.1 aHsueh, K., L.1 aMaia, C.1 aAbad-Campos, P1 aLeón, M1 aJung, Horta uhttp://doi.wiley.com/10.1111/ppa.12564http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fppa.1256403359nas a2200277 4500008004100000245010800041210006900149300001100218520245100229100001702680700001902697700003902716700002102755700001902776700002302795700002302818700003202841700002002873700001802893700002402911700002202935700002002957700002502977700001703002856006203019 2018 eng d00aDiversity of Phytophthora species in Valdivian rainforests and association with severe dieback symptoms0 aDiversity of Phytophthora species in Valdivian rainforests and a ae124433 a

The Valdivian rainforest, one of the global hotspots of biodiversity, is a temperate rainforest originating as a Tertiary relic from the supercontinent Gondwana. In November 2014, a survey of Phytophthora diversity was performed in 13 natural forest stands and 20 forest streams and rivers in two protected areas near Valdivia and in a temperate montane forest in the Concepción area. One planted stand each of the introduced tree species Castanea sativa and Fagus sylvatica were also included. Using baiting assays, eight described species and four previously unknown taxa of Phytophthora were isolated from 86% of the 50 rhizosphere soil samples from seven of the eight tree species sampled in 12 forest stands, and from 20 streams: P. chlamydospora, P. cinnamomi, P. kernoviae, P. lacustris, P. plurivora, P. pseudosyringae, P. ×cambivora, P×stagnum, P. valdiviana nom. prov. from Clade 2b, P. madida nom. prov. from Clade 8a, and P. chilensis nom. prov. and P. pseudokernoviae nom. prov. The latter two species are the closest relatives of P. kernoviae from Clade 10. Phytophthora pseudokernoviae nom. prov. was also isolated from necrotic leaves of Drimys winteri. From the Valdivia river, a swarm of three Clade 6 hybrids was recovered. Each hybrid isolate resulted from multiple reticulation events with P. thermophila as maternal and both P. amnicola and P. chlamydospora as paternal parents. In addition, three previously unknown and recently described Nothophytophthora species, N. caduca, N. chlamydospora and N. valdiviana, were isolated from several forest streams. Phytophthora cinnamomi, the most common and widespread species in soils of native forests, was associated with severe dieback of Valdivian rainforest trees, in particular D. winteri, Luma apiculata, Nothofagus dombeyi and the endangered Saxegothaea conspicua. A first pathogenicity test demonstrated high aggressiveness of P. cinnamomi to several native tree species, including N. dombeyi, Blepharocalyx cruckshanksii and Gevuina avellana.

1 aJung, Thomas1 aDurán, Alvaro1 avon Stowasser, Eugenio, Sanfuentes1 aSchena, Leonardo1 aMosca, Saveria1 aFajardo, Sebastian1 aGonzález, Mariela1 aOrtega, Angella, D. Navarro1 aBakonyi, Jozsef1 aSeress, Diana1 aTomšovský, Michal1 aCravador, Alfredo1 aMaia, Cristiana1 aJung, Marilia, Horta1 aWoodward, S. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1244300992nas a2200313 4500008004100000245008700041210006900128260011100197300000800308490003200316100001600348700001600364700001600380700001800396700001800414700001300432700001600445700001400461700001400475700001500489700001400504700001400518700001500532700001500547700001700562700001700579700001800596856006400614 2010 eng d00aDetection and eradication of Phytophthora ramorum from Oregon forests, 2001–20080 aDetection and eradication of Phytophthora ramorum from Oregon fo aSanta Cruz, CaliforniabU.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station a3-50 vGen. Tech. Rep. PSW-GTR-2291 aKanaskie, A1 aHansen, E M1 aGoheen, E M1 aOsterbauer, N1 aMcWilliams, M1 aLaine, J1 aThompson, M1 aSavona, S1 aTimeus, H1 aWoosley, B1 aSutton, W1 aReeser, P1 aSchultz, R1 aHilburn, D1 aFrankel, S J1 aKliejunas, T1 aPalmieri, K M uhttp://www.fs.fed.us/psw/publications/documents/psw_gtr229/00565nas a2200145 4500008004100000022001400041245011300055210006900168300001400237490000800251653001500259100002200274700002300296856010000319 2004 eng d a0378-112700aThe decline of Austrocedrus chilensis forests in Patagonia, Argentina: soil features as predisposing factors0 adecline of Austrocedrus chilensis forests in Patagonia Argentina a345 - 3570 v19010aTopography1 aLa Manna, Ludmila1 aRajchenberg, Mario uhttp://www.sciencedirect.com/science/article/B6T6X-4BD5PHG-4/2/6181ecf7a2cf4ba397d9afef97ee478d00493nas a2200085 4500008004100000245014000041210006900181100002100250856013600271 2008 eng d00aDeveloping techniques for evaluating the susceptibility of root-disease resistant Port-Orford-Cedar to foliar and stem canker diseases.0 aDeveloping techniques for evaluating the susceptibility of rootd1 aMartin, Danielle uhttps://forestphytophthoras.org/references/developing-techniques-evaluating-susceptibility-root-disease-resistant-port-orford-cedar01830nas a2200157 4500008004100000022001400041245006800055210006800123260002900191300001400220490000700234520134500241100001601586700001501602856005501617 2011 eng d a1439-032900aDiplanetism and microcyclic sporulation in Phytophthora ramorum0 aDiplanetism and microcyclic sporulation in Phytophthora ramorum bBlackwell Publishing Ltd a349–3540 v413 a

The zoosporic phase of the pathogen Phytophthora ramorum plays a crucial role in the process of plant infection, yet little is known about the fate of zoospores failing to target their hosts. Here, we describe new stages in the life cycle of P. ramorum concerning the in vitro development of monomorphic diplanetism and microcyclic sporulation in free water. Papillate cysts were formed after zoospore suspensions of isolates of the EU1 and NA1 clonal lineages were vortexed. Cysts usually germinated directly forming an emerging tube, or indirectly by releasing a secondary zoospore, which leaves behind an empty cyst with a short evacuation tube. Germinate cysts frequently developed either an appressorium or a microsporangium both terminally. We also observed microcyclic sporulation, i.e. sporangia indirectly germinated by forming a microsporangium, as in microcyclic conidiation of true fungi. Temporal progress of encysted zoospores in solution showed that percentage of germination varied significantly among and within isolates as well as between experiments, suggesting that germination is partly ruled by internal mechanisms. Diplanetism and microcyclic sporulation in P. ramorum may provide a second opportunity for host infection and may increase the chance of long dispersal in moving water.

1 aMoralejo, E1 aDescals, E uhttp://dx.doi.org/10.1111/j.1439-0329.2010.00674.x01028nas a2200157 4500008004100000245013400041210006900175260001200244300001500256520046600271100001800737700001700755700001900772700001300791856006600804 2013 eng d00aDevelopment of a quantitative real-time PCR assay for the detection of Phytophthora austrocedrae, an emerging pathogen in Britain0 aDevelopment of a quantitative realtime PCR assay for the detecti c05/2013 aEarly view3 a

A TaqMan real-time PCR assay was developed for Phytophthora austrocedrae, an emerging pathogen causing severe damage to juniper in Britain. The primers amplified DNA of the target pathogen down to 1 pg of extracted DNA, in both the presence and absence of host DNA, but did not amplify any of the non-target Phytophthora and fungal species tested. The assay provides a useful tool for screening juniper populations for the disease.

1 aMulholland, V1 aSchlenzig, A1 aMacAskill, G A1 aGreen, S uhttp://onlinelibrary.wiley.com/doi/10.1111/efp.12058/abstract01958nas a2200217 4500008004100000022001300041245010400054210006900158260001200227300001600239490000800255520129900263100001501562700001401577700002001591700001301611700001301624700001401637700001801651856007101669 1999 eng d a0953756200aDiversity of Phytophthora megakarya in Central and West Africa revealed by isozyme and RAPD markers0 aDiversity of Phytophthora megakarya in Central and West Africa r c10/1999 a1225 - 12340 v1033 a

Phytophthora megakarya is an important pathogen of cocoa in Africa. We used isozyme and RAPD markers to estimate the genetic diversity and structuring among 161 isolates, from the known distribution area of the fungus which corresponds to the cocoa belt in Ghana, Togo, Nigeria, Cameroon, Gabon and Sao Tome. Thirty six and 44 multilocus patterns were identified with isozymes and RAPDs, respectively. Patterns were separated into two highly differentiated genetic groups with both types of markers, one located in Central Africa and the other in West Africa. This distribution coincides with two major biogeographical domains which may reflect an ancient evolution of P. megakarya in this part of Africa. The genotypic diversity was lower in West Africa as compared to Central Africa. Inside Central Africa, isolates from Gabon and Sao Tome were highly differentiated based on RAPDs. Four intermediate marker patterns corresponding to isolates sampled near the border between Nigeria and Cameroon were putatively derived from genetic exchanges between the two major groups. The mating type determination permitted to confirm the high prevalence of A1 over A2. Although clonal multiplication seems to be the rule, indices of other reproduction means have been detected.

1 aNyassÉ, S1 aGrivet, L1 aRisterucci, A M1 aBlaha, G1 aBerry, D1 aLanaud, C1 aDesprÉAux, D uhttp://www.sciencedirect.com/science/article/pii/S095375620860671100585nas a2200145 4500008004100000245010100041210006900142300001200211490000700223653002900230100001900259700001400278700001500292856013200307 1977 eng d00aDetection of Phytophthora lateralis in soil organic matter and factors that affect its survival.0 aDetection of Phytophthora lateralis in soil organic matter and f a79–840 v6710aChamaecyparis lawsoniana1 aOstrofsky, W D1 aRoth, L F1 aPratt, R G uhttps://forestphytophthoras.org/references/detection-phytophthora-lateralis-soil-organic-matter-and-factors-affect-its-survival02559nas a2200217 4500008004100000245017100041210006900212260001600281300001100297490000700308520180200315100002502117700002102142700001702163700002502180700001802205700001802223700002102241700001702262856006202279 2020 eng d00aDetection and spread of Phytophthora austrocedri within infected Juniperus communis woodland and diversity of co-associated Phytophthoras as revealed by metabarcoding0 aDetection and spread of Phytophthora austrocedri within infected cMay-17-2020 ae126020 v503 a

Phytophthora austrocedri is a recently invasive soilborne pathogen which is causing widespread mortality of Juniperus communis in northern Britain. The pathways by which a single genotype of P. austrocedri has spread to infect such a geographically dispersed range of woodland sites within a relatively short timeframe are unknown. This study examined the detectability of P. austrocedri in soil and water within infected J. communis woodland using qPCR to gain a better understanding of the pathogen's key mechanisms of spread. A Phytophthora metabarcoding method was also applied to investigate the wider diversity of Phytophthora species present in water at one of the sites. qPCR analyses of P. austrocedri in soil samples at a J. communis woodland exhibiting low‐to‐moderate levels of disease suggested a slow natural spread of the pathogen in soil, requiring high moisture conditions. However, the ubiquity of P. austrocedri DNA in soil samples collected across a heavily infected J. communis site suggests that once established at a site the pathogen can be spread readily in soil locally, most likely vectored by animal movements and/or human activities. The hypothesis that P. austrocedri is aerially transmitted in rainwater was not adequately proven, and an alternative hypothesis for the widespread distribution of the pathogen on J. communis in northern Britain is presented. Metabarcoding identified DNA from a diverse range of Phytophthora species in river and rainwater samples although the main target pathogen, P. austrocedri, was not amplified which disagreed with some of the qPCR findings. Possible reasons for this are discussed.

1 aRiddell, Carolyn, E.1 aDun, Heather, F.1 aElliot, Matt1 aArmstrong, April, C.1 aClark, Mhairi1 aForster, Jack1 aHedley, Pete, E.1 aGreen, Sarah uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/efp.1260202935nas a2200421 4500008004100000022001400041245009900055210006900154260002900223300001600252490000700268520164200275653003501917653001801952653003201970653001302002653002702015100002302042700002502065700002302090700002202113700001802135700001602153700002102169700002502190700002402215700002402239700001702263700002502280700002102305700001702326700002502343700002002368700002402388700002202412700002402434856005502458 2011 eng d a1755-099800aDNA barcoding of oomycetes with cytochrome c oxidase subunit I and internal transcribed spacer0 aDNA barcoding of oomycetes with cytochrome c oxidase subunit I a bBlackwell Publishing Ltd a1002–10110 v113 a

Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.

10acytochrome c oxidase subunit I10aDNA barcoding10ainternal transcribed spacer10aoomycete10aspecies identification1 aRobideau, Gregg, P1 aDe Cock, Arthur, W M1 aCoffey, Michael, D1 aVoglmayr, Hermann1 aBrouwer, Henk1 aBala, Kanak1 aChitty, David, W1 aDésaulniers, Nicole1 aEggertson, Quinn, A1 aGachon, Claire, M M1 aHu, Chia-Hui1 aKüpper, Frithjof, C1 aRintoul, Tara, L1 aSarhan, Ehab1 aVerstappen, Els, C P1 aZhang, Yonghong1 aBonants, Peter, J M1 aRistaino, Jean, B1 aAndré Lévesque, C uhttp://dx.doi.org/10.1111/j.1755-0998.2011.03041.x02559nas a2200145 4500008004100000245014900041210006900190260001600259300001200275490000700287520197400294100001302268700001902281856011302300 2016 eng d00aDieback and mortality of Nothofagus in Britain: ecology, pathogenicity and sporulation potential of the causal agent Phytophthora pseudosyringae0 aDieback and mortality of Nothofagus in Britain ecology pathogeni cJan-01-2016 a26 - 360 v653 a

Since 2009 extensive dieback and mortality of Nothofagus obliqua, associated with bleeding cankers on stems and branches, has been observed in the UK. The causal agent was identified as Phytophthora pseudosyringae, based on morphological and analysis of the internal transcribed spacer (ITS) sequences. Between 2011 and 2013, a survey assessed the frequency and nature of these P. pseudosyringae infections. Mature trees of Nothofagus with stem lesions caused by P. pseudosyringae were found across England, Scotland and Wales. Additional symptoms such as twig blight and leaf necrosis indicated that aerial infection was occurring. Besides N. obliqua, other hosts regularly encountered included Nothofagus alpina, Fagus sylvatica and Vaccinium myrtillus. In pathogenicity tests involving inoculation of logs, P. pseudosyringae was shown to be an aggressive bark pathogen of N. obliqua and F. sylvatica, but significantly less aggressive on N. alpina. Foliage susceptibility and sporulation tests showed marked differences between the six host species tested. Leaves of N. obliqua and V. myrtillus were highly susceptible. Leaves of N. alpina were moderately susceptible, those of Rhododendron ponticum slightly susceptible and those of F. sylvatica not susceptible at all. High levels of sporulation were observed only on inoculated N. obliqua and V. myrtillus leaves. This suggests that P. pseudosyringae may sporulate heavily on N. obliqua foliage in the field and that this inoculum initiates the aerial lesions observed on the shoots, branches and stems. The results also suggest that P. pseudosyringae has the potential to pose a serious threat to N. obliqua and other Nothofagus species in their Southern Hemisphere native ranges.

1 aScanu, B1 aWebber, J., F. uhttp://doi.wiley.com/10.1111/ppa.12399http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fppa.1239901416nas a2200169 4500008004100000022001400041245010700055210006900162300001400231520086100245100001701106700001601123700002101139700001301160700001801173856005501191 2012 eng d a1439-032900aDetecting asymptomatic ink-diseased chestnut trees by the composition of the ectomycorrhizal community0 aDetecting asymptomatic inkdiseased chestnut trees by the composi an/a–n/a3 aThe research was performed in a new and isolated ink disease outbreak. Nine sweet chestnuts of comparable age, growing under same environmental and site conditions, and belonging to three phytosanitary classes (healthy, infected but asymptomatic and symptomatic) were randomly selected. Their ectomycorrhizal community was monitored during two periods, with regard to species abundance, to verify whether the community composition can be useful as an ink disease bioindicator. From the 216 samples, 29 ectomycorrhizal species were recorded, with abundances that changed with the health status of the tree. The results demonstrated that the mycorrhizal community composition was highly related to the ink disease level, allowing the consideration of the use of this parameter as a tool for the quick detection and control of the early stages of the disease.1 aScattolin, L1 aDal Maso, E1 aMutto Accordi, S1 aSella, L1 aMontecchio, L uhttp://dx.doi.org/10.1111/j.1439-0329.2012.00784.x01465nas a2200145 4500008004100000022001400041245011100055210006900166260002900235300001200264490000700276520096400283100001701247856005501264 2011 eng d a1365-233800aA duplex PCR method for the simultaneous identification of Phytophthora ramorum and Phytophthora kernoviae0 aduplex PCR method for the simultaneous identification of Phytoph bBlackwell Publishing Ltd a27–290 v413 a

Phytophthora ramorum and Phytophthora kernoviae are two fungus-like organisms affecting a wide range of hardy ornamental plants and trees. Emergency measures are implemented in the European Union for P. ramorum and aim to eradicate, or at least prevent the further spread of this harmful pathogen. Phytophthora kernoviae has so far been found only in New Zealand, the UK and Ireland, and is regulated on a UK level using the same measures as for P. ramorum. Both Phytophthora species have a similar host range and can be diagnosed using similar methods. Therefore a duplex PCR detection, based on the internal transcribed spacer (ITS) regions of the ribosomal DNA, was developed to enable simultaneous testing to reduce diagnostic times. The method was tested for its specificity and sensitivity, and on plant samples, and was shown to be reliable for identification of the two organisms.

1 aSchlenzig, A uhttp://dx.doi.org/10.1111/j.1365-2338.2010.02431.x02295nas a2200253 4500008004100000022001400041245017700055210006900232260001200301300001400313490000700327520139900334100001601733700001501749700001701764700001201781700001701793700001601810700002101826700002001847700002301867700001501890856013601905 1999 eng d a1437-478100aDetection and quantification of Phytophthora species which are associated with root-rot diseases in European deciduous forests by species-specific polymerase chain reaction0 aDetection and quantification of Phytophthora species which are a c06/1999 a169 - 1880 v293 a

Oligonucleotide primers were developed for the polymerase chain reaction (PCR)-based detection of selected Phytophthora species which are known to cause root-rot diseases in European forest trees. The primer pair CITR1/CITR2, complementing both internal transcribed spacer regions of the ribosomal RNA genes, gave a 711 bp amplicon with Phytophthora citricola. The Phytophthora cambivora specific primer pair CAMB3/CAMB4, producing a 1105bp amplicon, as well as the Phytophthora quercina specific primer pair QUERC1/QUERC2, producing a 842 bp amplicon, were derived from randomly amplified polymorphic DNA (RAPD)-fragments presented in this paper. All three primer pairs revealed no undesirable cross-reaction with a diverse test collection of isolates including other Phytophthora species, Pythium, Xerocomus, Hebeloma, Russula, and Armillaria. Under the PCR conditions described the detection of a well discernable amplicon was possible down to 100 pg (P. cambivora), 4pg (P. quercina), and 2pg (P. citricola) target DNA. This diagnostic PCR system was able to detect P. citricola, P. quercina, and P. cambivora in seedlings of pendunculate oak (Quercus robur) and European beech (Fagus sylvatica) which were artificially infected under controlled conditions.

1 aSchubert, R1 aBahnweg, G1 aNechwatal, J1 aJung, T1 aCooke, D E L1 aDuncan, J M1 aMuller-Starck, G1 aLangebartels, C1 aSandermann, Jr2, H1 aOsswald, W uhttps://forestphytophthoras.org/references/detection-and-quantification-phytophthora-species-which-are-associated-root-rot-diseases03910nas a2200193 4500008004100000022001400041245009700055210006900152260001200221300001400233490000700247520333100254100001303585700001503598700002003613700002003633700001303653856005003666 2014 eng d a0191-291700aDieback and Mortality of Pinus radiata Trees in Italy Associated with Phytophthora cryptogea0 aDieback and Mortality of Pinus radiata Trees in Italy Associated c01/2014 a159 - 1590 v983 a

Pinus radiata D. Don is a forest tree species native to the Monterey Baja in California. Due to its rapid growth and desirable lumber and pulp qualities, between 1960 and 1980, about 12,000 ha of P. radiata were planted in Sardinia, Italy. The only disease reported on this conifer species has been Diplodia pinea, which causes tip and branch dieback (3). In January 2012, dieback and mortality of 25-year-old radiata pine trees were observed in a reforestation area of about 20 ha located in northern Sardinia (40°43′N, 9°22′E, 600 m a.s.l.). Symptoms included chlorosis, reddish-brown discoloration of the whole crown or dieback starting in the upper crown and progressing downward through the crown, and necrotic bark tissues at root collar. Approximately 25% of the trees were affected. In a first attempt, a Phytophthora species was consistently isolated from the rhizosphere of 23 symptomatic trees, which included necrotic fine roots using oak leaves as bait (4). Afterwards, it was also isolated from phloem samples taken from the margins of fresh lesions at the stem base and upper roots of affected trees using synthetic mucor agar medium (1). Isolation from soil samples of six healthy pine trees randomly selected in the site did not yield any Phytophthora isolate. On carrot agar (CA), Phytophthora colonies were stellate to slightly radiate with limited aerial mycelium. Sporangia were obpiryform, non-papillate, and non-caducous, measuring 46.9 to 51.2 × 29.1 to 32.6 μm (l:b ratio 1.9). Hyphal swellings were formed in chains or clusters; chlamydospores were not observed. These isolates had cardinal temperatures of <5°C, 25°C, and 35°C, respectively. Their morphological and cultural features were typical of Phytophthora cryptogea Pethybridge & Lafferty. They were heterothallic and produced oogonia with amphyginous antheridia when paired with an A2 mating type tester strain of P. cryptogea. This identity was corroborated by sequence analysis of the internal transcribed spacer (ITS) region of the rDNA. BLAST searches showed 99% homology with sequences of P. cryptogea available in GenBank (DQ479410 and HQ697245). The ITS sequence of a representative isolate (PH101) was submitted to GenBank (Accession Nos. KC603895). The strain PH101 was stored in the culture collection of the Department of Agriculture at the University of Sassari. Pathogenicity of isolate PH101 was verified by inoculating five freshly cut logs of radiata pine (1 m long and 15 cm diam.) with a 5-mm agar plug taken from the margin of 4-day-old culture grown on CA (4). The plug was inserted in a 5-mm hole made through the bark with a cork borer. Five control logs were inoculated with sterile CA. All logs were incubated in a growth chamber at 20°C. Phloem lesion sizes were assessed after 1 month and measured 9.7 ± 5.5 cm2 (average ± standard deviation). Control logs had no lesions. The pathogen was re-isolated from the lesions, thus fulfilling Koch's postulates. P. cryptogea has been previously reported in Australia, causing decline of radiata pine trees in wet and flooded soils (2). To our knowledge, this is the first report of P. cryptogea on P. radiata trees in Europe.

1 aSechi, C1 aSeddaiu, S1 aLinaldeddu, B T1 aFranceschini, A1 aScanu, B uhttp://dx.doi.org/10.1094/PDIS-05-13-0572-PDN01921nas a2200133 4500008004100000245005500041210005400096300000800150490000700158520149500165100001501660700001801675856009401693 2010 eng d00aDetection and identification of Phytophthora alni.0 aDetection and identification of Phytophthora alni a6550 v753 a

In 2004 Brasier et al. described new species–Phytophthora alni, which was especially aeggressive to alder. Now, this Phytophthora disease of alder is widely distributed in Europe as well as in Poland. In this research note we report on identification and detection of P. alni from water and soil samples using PCR method with species-specific primers. Dilution series of P. alni zoospore were used to test the potential sensitivity of the PCR detection methods. Zoospores of P. alni were produced by flooding of 1-week-old Frozen Pea Medium (FPM) cultures in Petri dishes with 30 ml distilled water. The dishes were incubated at 20 degrees C. After 5 days, sporangial production was checked using a binocular microscope and plates were placed at 4 degrees C for 1 h to enhance zoospore release. Zoospores were counted under the microscope using Burker’s cabin. A dilution series of zoospores ranging from 5 to 5000 per 200 microl was prepared in autoclaved distilled water and in 1 g samples of autoclaved soil. DNA was extracted from artificially infected water and soil, and purified using the CleanUp Kit (A&A Biotechnology). Zoospores of P. alni in the water were detected by PCR in 5 x 10(3), 5 x 10(2), 5 x 10(1) concentrations. In case of detecting spores in the artificially infected soil it succeeded only for two highest concentrations, i.e. 5 x 10(3), 5 x 10(2) and only when the DNA was additionally purified.

1 aTrzewik, A1 aOrlikowska, T uhttps://forestphytophthoras.org/references/detection-and-identification-phytophthora-alni02470nas a2200229 4500008004100000022001300041245007600054210006900130260001600199300001600215490000800231520175000239100002101989700002402010700002102034700002602055700002302081700002802104700001902132700002302151856006602174 2012 eng d a1878614600aDiscovery of a fourth evolutionary lineage of Phytophthora ramorum: EU20 aDiscovery of a fourth evolutionary lineage of Phytophthora ramor cJan-11-2012 a1178 - 11910 v1163 a

Phytophthora ramorum is a recently introduced, aggressive Phytophthora species that has caused extensive mortality of oak and tanoak trees in the western USA and Japanese larch trees in the UK. P. ramorum is also present on Rhododendron, Camellia, and Viburnum in the nursery industry, which is thought to have been the pathway for its spread into new geographic regions including forests and natural ecosystems. Three lineages of P. ramorum have been described, informally designated EU1, NA1, and NA2, and each lineage is believed to originate from an as yet unknown exotic centre of origin. Preliminary SSR and sequence analysis of isolates from a UK P. ramorum survey revealed seven isolates with profiles that did not match the previously known lineages. Detailed SSR and multilocus sequence analysis of these isolates are presented, allowing us to assign these isolates to a new P. ramorum lineage, designated EU2. Although the known geographical origin of these isolates is currently limited to Northern Ireland and western Scotland, the EU2 lineage isolates have been obtained from four different host plants, including Japanese larch. All isolates are of A1 compatibility type, which implies that this finding does not increase the risk of outcrossing with the EU1 lineage isolates already present in the UK. The oldest EU2 strain was isolated in 2007 but no SSR-based intraEU2 lineage genotypic diversity was detected. The combination of these elements points to a recent introduction, despite emergency phytosanitary measures to control introduction and spread. A PCR-RFLP method for the rapid identification of EU2 lineage isolates is presented.

1 aVan Poucke, Kris1 aFranceschini, Selma1 aWebber, Joan, F.1 aVercauteren, Annelies1 aTurner, Judith, A.1 aMcCracken, Alistair, R.1 aHeungens, Kurt1 aBrasier, Clive, M. uhttp://linkinghub.elsevier.com/retrieve/pii/S187861461200157204270nas a2200145 4500008004100000245012300041210006900164300000700233490000700240520377500247100001504022700001504037700001704052856005504069 2010 eng d00aDieback and mortality of plantation Japanese larch (Larix kaempferi) associated with infection by Phytophthora ramorum0 aDieback and mortality of plantation Japanese larch Larix kaempfe a190 v223 a

The invasive pathogen Phytophthora ramorum is the cause of ’sudden oak death’, a dieback and mortality of more than one million live-oak and tanoak trees along 1500 km of near-coastal native forest in California and Oregon since 1995 (Rizzo et al., 2002; Frankel, 2008). P. ramorum has also spread across Europe , mainly within the ornamental nursery trade. From 2003 onwards it was found infecting rhododendron and woodland trees outside nurseries in Britain (Brasier et al., 2004) and has recently spread to native Vaccinium swards (P. Beales, personal communication). Until now, tree infections in Britain have been comparatively few (<100), mostly foliage or stems of Fagaceae (Fagus, Nothofagus, Quercus and Castanea) in the vicinity of infected Rhododendron in south west England (Webber, 2008). In August 2009 extensive dieback and mortality was observed in mature (25-30 m tall) and juvenile plantation Japanese larch, Larix kaempferi,at multiple sites in south west England (Figs. 1, 2). Symptoms included black or purple discoloured needles (Fig. 3), aborted bud flush, wilting and senescence of dwarf shoots and needle loss. Affected trees often had copious resin bleeding on the trunk, branches and side shoots plus dieback of branches and sometimes of the entire crown. Phloem lesions were often present under resinous outer bark. These usually had deep pink to maroon-red margins, older lesion areas being rusty-brown to cinnamon brown.

When symptom-bearing needles were surface-sterilised in 70% ethanol for 30 seconds or small pieces of older phloem lesion were plated onto Phytophthora selective medium (Brasier et al., 2005), P. ramorum was obtained from 25-40% of the samples. Identity was confirmed by sequencing of ITS rDNA regions (GenBank Accession No. HQ010359). P. ramorum was not obtained from the pink-maroon lesion margins. Pathogenicity of a P. ramorum isolate from L. kaempferi was tested by dipping 15 cm long L. kaempferi shoots into a zoospore suspension and damp chamber incubating for 12h light/12h dark cycle at 18°C. On half the shoots all needles were wounded by tip cutting. After seven days each needle was categorised as blackened, browned/brown bands, chlorotic or green, surface sterilised and plated onto selective medium. Both unwounded and wounded blackened needles yielded P. ramorum at high frequency (Table 1). When needles were mounted in lactic acid cotton blue and viewed 24 h later, sporangia and occasionally chlamydospores were observed on the surfaces with an exceptional 2685 sporangia counted on one unwounded needle (Fig. 4).

P. ramorum has so far been isolated from L. kaempferi at 68 currently known plantations where symptoms are present in southwest England . In May 2010 larch plantations with similar symptoms were discovered in south Wales and P. ramorum has again been isolated at multiple sites. Overall an estimated 2400 ha or c. 0.6 million mature larch have been affected to date. A large area of juvenile larch is also affected. This is the first widespread and lethal damage caused by P. ramorum to a conifer and the first to a commercial plantation tree. Adjacent to some affected larch sites in southwest England , secondary infection of Fagus sylvatica, Nothofagus obliqua, Castanea sativa, Betula pendula, Rhododendron ponticum, Tsuga heterophylla and Pseudotsuga menziesii is also occurring, apparently as result of the high levels of P. ramorum inoculum produced from larch foliage.  

1 aWebber, JF1 aMullett, M1 aBrasier, C M uhttp://dx.doi.org/10.5197/j.2044-0588.2010.022.01902403nas a2200193 4500008004100000245016200041210006900203260001700272300001600289490000700305520175200312100001202064700001702076700001302093700001402106700001502120700001502135856005902150 2009 eng d00aDifferential behaviour in pathogenicity and enzymatic activities of Phytophthora katsurae strains from coconut trees in Côte d’Ivoire. [Article in French]0 aDifferential behaviour in pathogenicity and enzymatic activities bFACT Limited a1246–12570 v213 a

An experiment was conducted to study epidemiological variation of Phytophthora katsurae on coconut trees from four farming areas. Isolates of the pathogenic agent were first characterized based on morphology of sporocysts, oospore, chlamydospore and mycelium, and this enabled detection of differences between the aggressiveness of strains. Differences were also detected when measuring the mycelium growth of each strain in vitro on different culture media (V8, Malt and Carotte). A second study was conducted to confirm the observed differences based on inoculation (gentle or rough) of coconut plants cv. Equatoriale Guinea Green Dwarf (NVE), which is susceptible to P. katsurae, with each of four strains. Last, the enzymatic dosages of pectate lyase and laccase in pathogen were analysed. These enzymes degrade the pectin and lignin of the plant cell walls. Gentle inoculation enabled assessment of the level of aggressiveness of each strain. The activity of pectate lyase and laccase varied between the strains and the synthesis of these enzymes was correlated to pathogen aggressiveness on the plant. The results showed that the strains of Marc Delorme and Assinie are less aggressive than the strain of Fresco, which is less aggressive than the strain of Robert Michaux. The zoospores and the mycelia are considered as the primary inoculum of the four strains. The β-sitosterol added to V8 medium had no influence on the mycelium growth of the four strains. However, its use as ingredient added to the media favoured an increased production of sporocysts. The discovery of this intra specific variability should be of considerable help in elaborating control methods against P. katsurae of coconut trees.

1 aYao, NR1 aN’Goran, B1 aAllou, K1 aDogbo, DO1 aKonan, KJL1 aKouassi, P uhttp://www.m.elewa.org/JABS/2009/21/Abstract4-Yao.html