02274nas a2200193 4500008004100000022001400041245019500055210006900250260001600319300001600335490000800351520148100359100002401840700002301864700002501887700002001912700001701932856013101949 2017 eng d a0031-949X00aMorphological and genetic analyses of the invasive forest pathogen Phytophthora austrocedri reveal that two clonal lineages colonized Britain and Argentina from a common ancestral population0 aMorphological and genetic analyses of the invasive forest pathog cJan-12-2017 a1532 - 15400 v1073 a

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15°C and all isolates were killed at 25°C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

1 aHenricot, Béatrice1 aPérez-Sierra, Ana1 aArmstrong, April, C.1 aSharp, Paul, M.1 aGreen, Sarah uhttps://apsjournals.apsnet.org/doi/10.1094/PHYTO-03-17-0126-Rhttps://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-03-17-0126-R