Comparative analysis of genomes reveals oomycete pathogenesis in crops.

The oomycete genus includes devastating plant pathogens that are found in almost all ecosystems. We sequenced the genomes of two quarantined species- and . Comparing these species and related genera allowed reconstruction of the phylogenetic relationships within the genus and revealed genomic features associated with infection and pathogenicity. We found that several hundred genes are putatively inherited from red algae, but does not have vestigial plastids originating from phototrophs. The horizontally-transferred genes are abundant transposons that "transmit" exogenous gene to species thus bring about the gene recombination possibility. Several expansion events of gene families associated with cell wall biogenesis can be used as mutational targets to elucidate gene function in pathogenic interactions with host plants. This work enhanced the understanding of evolution and will also be helpful for the design of phytopathological control strategies.