Population structure of an aerial Phytophthora species in forest systems
S. BRAR (1), R. Bradshaw (1), R. McDougal (2), N. Williams (3) (1) Massey University, New Zealand; (2) Scion New Zealand Forest Research Institute Ltd, New Zealand; (3) Scion New Zealand Forest Research Institute Ltd, New Zealand

Phytophthora pluvialis is a foliar pathogen that was recently identified as the causal agent of red needle cast on Pinus radiata in New Zealand. P. pluvialis was first discovered in New Zealand in 2008 but had previously been recovered from Tanoak and Douglas fir trees in Oregon (USA) in 2002. P. pluvialis was subsequently described as a new species in 2013 and is classified in Phytophthora clade 3 based on the ITS region. A collection of 140 P. pluvialis isolates from Scion (Rotorua, New Zealand) are being used for this study. The isolates were verified as P. pluvialis by using species specific primers Ypap2F and Ypap2R targeting the ypt1 gene. For a preliminary analysis of genetic diversity, the cox spacer region was amplified using Phytophthora specific primers FMPh8 and FMPh10. In Oregon seven unique haplotypes of P. pluvialis were identified using the cox spacer sequence. The cox spacer sequences from the New Zealand population were aligned to the seven Oregon haplotype sequences and assessed for similarities. All the New Zealand samples had the same cox spacer region sequence as Oregon sample MDR-5-010307 (haplotype 3). The aim of this project is to determine the genetic diversity and population structure of P. pluvialis in New Zealand using single nucleotide polymorphism (SNP) markers. A panel of 32 SNP markers have been designed and validated that will be used to genotype the P. pluvialis population. The results from this study will help determine if P. pluvialis was an introduced pathogen in New Zealand.

Abstract Number: P13-409
Session Type: Poster