Diversity and clonality in populations of Phytophthora citrophthora and P. syringae causing brown rot of citrus in California. Phytophthora

Phytophthora citrophthora and P. syringae are currently the primary causal organisms of brown rot of citrus fruits in California. To possibly find an explanation for the prevalence of the previously minor species P. syringae, we determined the population structures of both pathogens in California using next-generation sequencing and population genomics analyses. Whole genome sequencing and aligning with newly assembled reference genomes identified 972,266 variants in 132 isolates of P. citrophthora and 422,208 variants in 154 isolates (including 24 from non-citrus tree crops) of P. syringae originating from three major growing regions.