01694nas a2200217 4500008004100000022001400041245007900055210006900134260002900203300001100232490000700243520106400250100001501314700001701329700001301346700001701359700001301376700001301389700001901402856005501421 2011 eng d a1439-032900aPhenotypic differences among three clonal lineages of Phytophthora ramorum0 aPhenotypic differences among three clonal lineages of Phytophtho bBlackwell Publishing Ltd a7–140 v413 a

There are three major clonal lineages of Phytophthora ramorum present in North America and Europe named NA1, NA2, and EU1. Twenty-three isolates representing all three lineages were evaluated for phenotype including (i) aggressiveness on detached Rhododendron leaves and (ii) growth rate at minimum, optimum, and maximum temperatures. Closely related species P. foliorum and P. hibernalis were included in phenotypic tests since these species are encountered in nursery surveys for P. ramorum. Isolates from the NA2 and EU1 lineages were the most aggressive and isolates from the NA1 group were the least aggressive. The NA1 lineage of P. ramorum was the most variable in aggressiveness and growth rate. The variability in the NA1 lineage was due to the presence of non-wild type (nwt) isolates. There was no significant difference in growth rate among NA1 wild type (wt), NA2, and EU1 lineages at any temperature tested. The difference between wt and nwt P. ramorum isolates is discussed.

1 aElliott, M1 aSumampong, G1 aVarga, A1 aShamoun, S F1 aJames, D1 aMasri, S1 aGrünwald, N J uhttp://dx.doi.org/10.1111/j.1439-0329.2009.00627.x02015nas a2200229 4500008004100000022001400041245011600055210006900171260002900240300001400269490000700283520131600290100001501606700001701621700001301638700001701651700001301668700001301681700001701694700001901711856005501730 2009 eng d a1439-032900aPCR-RFLP markers identify three lineages of the North American and European populations of Phytophthora ramorum0 aPCRRFLP markers identify three lineages of the North American an bBlackwell Publishing Ltd a266–2780 v393 a

Phytophthora ramorum, the cause of sudden oak death and ramorum blight, has three major clonal lineages and two mating types. Molecular tests currently available for detecting P. ramorum do not distinguish between clonal lineages and mating type is determined by cultural methods on a limited number of samples. In some molecular diagnostic tests, cross-reaction with other closely related species such as P. hibernalis, P. foliorum or P. lateralis can occur. Regions in the mitochondrial gene Cox1 are different among P. ramorum lineages and mitochondrial genotyping of the North American and European populations seems to be sufficient to differentiate between mating types, because the EU1 lineage is mostly A1 and both NA1 and NA2 lineages are A2. In our study, we were able to identify P. ramorum isolates according to lineage using polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) of the Cox1 gene, first by using ApoI to separate P. ramorum from other species and EU1 from North American populations, and then AvaI to distinguish between NA1 and NA2 genotypes. However, P. foliorum had the same restriction profile as P. ramorum NA1 isolates.

1 aElliott, M1 aSumampong, G1 aVarga, A1 aShamoun, S F1 aJames, D1 aMasri, S1 aBrière, S C1 aGrünwald, N J uhttp://dx.doi.org/10.1111/j.1439-0329.2008.00586.x