The devastating oomycete phytopathogen Phytophthora cactorum: Insights into its biology and molecular features.

Phytophthora cactorum is one of the most economically important soilborne oomycete pathogens in the world. It infects more than 200 plant species spanning 54 families, most of which are herbaceous and woody species. Although traditionally considered to be a generalist, marked differences of P. cactorum isolates occur in degree of pathogenicity to different hosts. As the impact of crop loss caused by this species has increased recently, there has been a tremendous increase in the development of new tools, resources, and management strategies to study and combat this devastating pathogen. This review aims to integrate recent molecular biology analyses of P. cactorum with the current knowledge of the cellular and genetic basis of its growth, development, and host infection. The goal is to provide a framework for further studies of P. cactorum by highlighting important biological and molecular features, shedding light on the functions of pathogenicity factors, and developing effective control measures. TAXONOMY: P. cactorum (Leb. & Cohn) Schröeter: kingdom Chromista; phylum Oomycota; class Oomycetes; order Peronosporales; family Peronosporaceae; genus Phytophthora. HOST RANGE: Infects about 200 plant species in 154 genera representing 54 families. Economically important host plants include strawberry, apple, pear, Panax spp., and walnut. DISEASE SYMPTOMS: The soilborne pathogen often causes root, stem, collar, crown, and fruit rots, as well as foliar infection, stem canker, and seedling damping off.