02058nas a2200205 4500008004100000245012900041210006900170260001200239300001400251490000700265520139800272100001401670700001801684700001501702700001901717700001801736700001801754700001401772856006601786 2013 eng d00aA TaqMan real-time PCR assay for the detection of Phytophthora ‘taxon Agathis’ in soil, pathogen of Kauri in New Zealand0 aTaqMan realtime PCR assay for the detection of Phytophthora taxo c04/2013 a324–3300 v433 a

Kauri Agathis australis, an iconic tree of New Zealand, is under threat from an introduced disease-causing pathogen provisionally named Phytophthora ‘taxon Agathis’ (referred to as PTA). This soilborne, Pythiaceous species belongs to the Chromista and causes a collar rot resulting in yellowing of the foliage and thinning of the canopy, which eventually causes death of the infected tree. The management and containment of this pathogen requires rapid and reliable detection in the soil. The current method for soil detection utilizes a soil bioassay involving lupin baits and soil flooding in a process that takes between ten and twenty days. We describe a real-time PCR assay based on TaqMan chemistry for the specific detection of PTA, which targets the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. This TaqMan real-time PCR assay could be used with DNA extracted directly from bulk soil samples to enable rapid quantification of PTA within soil. The detection limit was 2 fg of PTA DNA from pure culture, or 20 fg in the presence of DNA extracted from soil. The assay was validated using soil samples taken from a PTA-infested site and soil spiked with a known concentration of oospores. We conclude that the TaqMan real-time PCR assay offers a more time-efficient method for detection of PTA in soil than existing methods.

1 aThan, D J1 aHughes, K J D1 aBoonhan, N1 aTomlinson, J A1 aWoodhall, J W1 aBellgard, S E1 aAndrea, V uhttp://onlinelibrary.wiley.com/doi/10.1111/efp.12034/abstract