01830nas 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.x04475nas a2200169 4500008004100000022001400041245006900055210006800124260001600192300001400208490000700222520383400229100001604063700001304079700002504092856018804117 2004 eng d a0032-086200aFirst report of Phytophthora tentaculata on Verbena sp. in Spain0 aFirst report of Phytophthora tentaculata on Verbena sp in Spain cJan-12-2004 a806 - 8060 v533 a

The oomycete Phytophthora tentaculata causes root and stalk rot of Chrysanthemum spp., Delphinium ajacis and Verbena spp. in nurseries in the Netherlands and Germany (Kröber & Marwitz, 1993). In June 2001, P. tentaculata was isolated from a young potted Verbena hybrid, showing a collar and stalk rot, in a nursery in Majorca (Balearic Islands, Spain). It was initially recovered by plating ∼10 mm pieces of necrotic tissue from the leading lesion on to a phytophthora selective medium, P5ARP (Erwin & Ribeiro, 1996). A pure culture (isolate CBS 115458) was obtained by transferring aseptically a hyphal tip onto corn meal agar (CMA) and was first identified from morphological characters.

The colony surface texture was uniform and formed sparse, loosely branched mycelium on carrot piece agar (CPA: 50 g carrot pieces and 20 g agar per 1000 mL distilled water) and CMA. The radial growth rate was 2–3 mm day−1 at 20°C on CMA. Sporangia did not appear on either agar media but formed readily in soil extract (50 g soil from a holm oak forest suspended in 1 L ionized water for 24 h at 20°C and then filtered and autoclaved). The sporangia were ovoid to globose, 27–52 (36·9) × 17–31 (24·6) µm, length:breadth ratio 1·4, papillate with a narrow exit pore, and some were caducous with a short pedicel (< 5 µm). Hyphal swellings were present in water. Chlamydospores were only seen on CMA after 2 weeks. Oogonia, readily produced on CPA in pure culture, were globose, mostly terminal or a few lateral, and ranged from 17 to 41 (34·0) µm in diameter. Single paragynous, monoclinous or diclinous, usually long-stalked antheridia were club-shaped or spherical, 9–16 (12·7) µm in diameter and many had appendages. Occasionally two paragynous antheridia per oogonium, as well as some amphigynous antheridia, were observed. Oospores were aplerotic 16–33 (28·4) µm in diameter and thin-walled.

To further confirm its identity, isozyme analysis based on malate dehydrogenase (EC 1.1.1.37) and malic enzymes (EC 1.1.1.40) was performed. Isozyme profiles fitted exactly those of three P. tentaculata strains: two strains ex-Chrysanthemum (including CBS 552.96 paratype) and one strain ex-Verbena; and differing from those of all other papillate species (Oudemans & Coffey, 1991a,b). Pathogenicity was assessed by flooding three potted Verbena plants with a 104 mL−1 zoospore suspension for 48 h at 20–22°C. As controls, two potted Verbena plants were flooded with ionized water. Controls remained healthy 15 days after inoculation. All three inoculated Verbena plants exhibited collar rot after 15 days, from which the pathogen was reisolated using PARP medium, thus confirming Koch's postulates. This is the first report of P. tentaculata in Spain.

1 aMoralejo, E1 aPuig, M.1 aVeld, W., A. Man in' uhttp://www.blackwell-synergy.com/toc/ppa/53/6http://doi.wiley.com/10.1111/j.1365-3059.2004.01089.xhttp://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3059.2004.01089.x01965nas a2200205 4500008004100000022001300041245008700054210006900141260001600210300001400226490000700240520134800247100001601595700002601611700001801637700001601655700001501671700001501686856005801701 2009 eng d a0032086200aMultiple alien Phytophthora taxa discovered on diseased ornamental plants in Spain0 aMultiple alien Phytophthora taxa discovered on diseased ornament cJan-02-2009 a100 - 1100 v583 a

The plant trade is unwittingly accelerating the worldwide spread of well‐known and new or undescribed Phytophthora species and creating novel niches for emerging pathogens. The results of a survey carried out from 2001 to 2006 in garden centres and nurseries of the Balearic Islands and eastern Spain combined with the analysis of samples received from ornamental nurseries from northern Spain reflected the extent of this global issue at the local scale. A total of 125 Phytophthora isolates were obtained from 37 different host species and 17 putative species identified on morphological features and direct sequencing of the internal transcribed spacer and four mitochondrial and nuclear genes. Five species, P. ramorum, P. hedraiandra, P. ‘niederhauserii’, P. ‘kelmania’ and P. ‘taxon Pgchlamydo’ were formally unknown to science prior to 2001. In addition, 37 new host/pathogen combinations were first records for Spain, highlighting the risk of non‐coevolved organisms from different biogeographic origins coming into contact under managed environments. The problem generated by new or rare taxa of Phytophthora found in nurseries for which no prior information on natural habitat and ecology is available for pest risk analysis is discussed.

1 aMoralejo, E1 aPérez-Sierra, A., M.1 aÁlvarez, L A1 aBelbahri, L1 aLefort, F.1 aDescals, E uhttp://doi.wiley.com/10.1111/j.1365-3059.2008.01930.x