Effector Repertoire of : In Search of Possible Virulence Factors Responsible for Its Host Specificity.

is an oomycete plant pathogen closely related to It infects tree tomato () in northern South America, but is, under natural conditions, unable to infect potatoes or tomatoes, the main hosts of its sister species . We characterized, and compared the effector repertoires of and other species. To this end, we used approaches to predict and describe the repertoire of secreted proteins in species and determine unique and core effectors. has the largest proteome and secretome of all species evaluated. We identified between 450 and 1933 candidate effector genes in , and genomes. The predicted secretome contains 5653 proteins, 1126 of which are apoplastic effectors and 807cytoplasmic effectors. Genes encoding cytoplasmic effectors include 791 genes with an RxLR domain (the largest number known so far in a species) and 16 with a Crinkler (CRN) domain. We detected homologs of previously described avirulence gene (Avr) present in spp., such as Avr1, Avr3b, Avr4, and Avrblb1, suggesting a high level of effector gene conservation among species. Nonetheless, fewer CRN effectors were obtained in compared to all other species analyzed. The comparison between and effector profiles shows unique features in that might be involved in pathogenesis and host preference. Indeed, 402 unique predicted effector genes were detected in , corresponding to 197 apoplastic effector genes, 203 RxLR cytoplasmic effector genes, and 2 effector genes with CRN domain. This is the first characterization of the effector profile of and the broadest comparison of predicted effector repertoires in the genus following a standardized prediction pipeline. The resultant putative effector repertoire provides a reasonable set of proteins whose experimental validation could lead to understand the specific virulence factors responsible for the host specificity of this species.