Enhanced TaqMan qPCR Assay for Phytophthora cinnamomi Detection and Quantification

Abstract

Phytophthora cinnamomi is one of the world's most invasive plant pathogens, requiring accurate detection in both plant and soil samples for effective disease management. This study compares existing qPCR assays with newly developed assays targeting the internal transcribed spacer (ITS) gene for improved detection. Our findings revealed that few current primers reliably distinguish P. cinnamomi from closely related species, and even those that did showed inadequate sensitivity. To address this, we designed novel primers and a species-specific probe targeting the ITS region, achieving consistent amplification with a detection limit of 10 fg. The new assay successfully detected P. cinnamomi in both artificial and symptomatic samples, ensuring rapid and precise identification. This optimised qPCR assay detects and quantifies P. cinnamomi in soil, providing superior sensitivity and specificity over existing methods and supporting more accurate pathogen management.