Phytophthora-ID.org: A Sequence-Based Phytophthora Identification Tool

Abstract

Contemporary species identification relies strongly on sequence-based identification, yet resources for identification of many fungal and oomycete pathogens are rare. We developed two web-based, searchable databases for rapid identification of Phytophthora spp. based on sequencing of the internal transcribed spacer (ITS) or the cytochrome oxidase (cox) 1 and 2 spacer region, followed by BLAST searching the databases. Both databases are highly selective. For ITS, only sequences associated with published Phytophthora spp. descriptions or classic Phytophthora phylogenetics references are included. For the cox spacer region, only data obtained by resequencing select isolates reported in published work were included. Novel taxa tentatively named are selectively included in the database and labeled as Phytophthora taxon "X"; as in, for example, P. taxon "asparagi". The database was validated with 700 Phytophthora isolates collected from nursery environments during 2006 to 2009. This resource, found at www.Phytophthora-ID.org , is a robust and validated tool for molecular identification of Phytophthora spp. and is regularly being updated.