Illuminating the Phytophthora capsici genome

Abstract

Phytophthora capsici is a devastating pathogen of vegetables including pepper, tomato, lima and snap beans, and most vining cucurbits. The epidemiology is highly dynamic and includes both sexual outcrossing and rapid asexual reproduction for propagation and survival. P. capsici infested fields often feature high levels of inoculum, genetic diversity, and dormant spores that can persist for many years. The overall genotypic diversity is impressive and is driven by meiosis as well as mitotic loss of heterozygosity. At many locations, P. capsici appears to be exotic and once introduced it is difficult to manage and often impossible to eradicate. Fungicide-resistant strains are common and there is a critical lack of resistant cultivars for all hosts. Genetic and genomic resources have recently been developed for P. capsici including a high-quality reference genome, a dense genetic linkage map, and thousands of validated single nucleotide polymorphism (SNP) markers. Although application of these tools is just beginning, they have already improved our understanding of genetics, genomics, genome stability, functional genomics, and the roles of secreted effector proteins that may underpin P. capsici virulence and epidemics. Here we highlight recent research advances and explore future directions of investigation.