02154nas a2200265 4500008004100000022001400041245015600055210006900211260002900280300001600309490000700325520128800332653002601620653002301646653001401669653001401683653002601697653002801723100001301751700001701764700002101781700001901802700001201821856005501833 2011 eng d a1365-305900aTwo novel and potentially endemic species of Phytophthora associated with episodic dieback of Kwongan vegetation in the south-west of Western Australia0 aTwo novel and potentially endemic species of Phytophthora associ bBlackwell Publishing Ltd a1055–10680 v603 a

Two novel homothallic species of Phytophthora causing dieback of Kwongan vegetation in south-west Western Australia are described here as Phytophthora arenaria sp. nov. and Phytophthora constricta sp. nov. DNA sequencing of the ITS rDNA and cox1 gene confirmed that P. arenaria and P. constricta are unique species residing in ITS clades 4 and 9, respectively. Phytophthora arenaria has been isolated from vegetation occurring on the northern sandplains which are warmer and drier than the southern sandplains from which P. constricta has been predominantly isolated, and both species appear morphologically and physiologically well adapted to the ecosystems in which they occur. Both species have been associated mainly with dead and dying Banksia species and the pathogenicity of both P. arenaria and P. constricta to Banksia attenuata was confirmed in this study. The combination of unique DNA sequences, including considerable variation in cox1 sequence data, thick oospore walls and physiological characteristics that appear to be adaptations favouring survival in the harsh Kwongan ecosystem suggest that these species may be endemic to Western Australia.

10aMediterranean climate10anatural ecosystems10apathogens10aphylogeny10aPhytophthora arenaria10aPhytophthora constricta1 aRea, A J1 aBurgess, T I1 aHardy, St, G E J1 aStukely, M J C1 aJung, T uhttp://dx.doi.org/10.1111/j.1365-3059.2011.02463.x