Non-host Plant Resistance against Is Mediated in Part by Members of the Gene Family in spp.

The identification of host genes associated with resistance to is crucial to developing strategies of control against this oomycete pathogen. Since there are few sources of resistance to in crop plants, non-host plants represent a promising source of resistance genes as well as excellent models to study - plant interactions. We have previously shown that non-host resistance to in spp. is mediated by the recognition of a specific effector protein, PcAvr3a1 in a manner that suggests the involvement of a cognate disease resistance (R) genes. Here, we have used virus-induced gene silencing (VIGS) and transgenic tobacco plants expressing dsRNA in spp. to identify candidate genes that mediate non-host resistance to . Silencing of members of the multigene family in the partially resistant plant and in the resistant resulted in compromised resistance to . VIGS of two other components required for gene-mediated resistance, and , also enhanced susceptibility to in , as well as in the susceptible plants and . The silencing of family members in also compromised the recognition of PcAvr3a1. These results indicate that in this case, non-host resistance is mediated by the same components normally associated with race-specific resistance.