The extracellular protease Rcr3 regulates jasmonic acid-dependent defence responses to damaging plant-parasitic nematodes in tomato

Recently, we showed that the effector GrVAP1 of the potato cyst nematode Globodera rostochiensis interacts with the Solanum pimpinellifolium allele of the extracellular cysteine protease Rcr3pim, but not with the corresponding Rcr3lyc allele of Solanum lycopersicum. GrVAP1 belongs to a family of secreted venom allergen-like proteins (VAPs), the members of which occur in all parasitic nematodes studied to date. The overexpression of nematode VAPs in plants selectively suppresses host defense responses mediated by surface-localized immune receptors. Furthermore, transgenic plants overexpressing VAPs show significantly altered sensitivity to exogenous methyljasmonate, but the function of Rcr3 (and homologous extracellular proteases) in this phenotype is not clear. However, tomato plants harboring Rcr3pim are far more susceptible to infections by plant parasitic nematode species that typically cause significant damage during host invasion. We analyzed the whole transcriptome of nematode-infected roots of tomato plants harboring Rcr3pim, Rcr3lyc, or rcr3-3, and found 28 genes uniquely associated with Rcr3pim. Most of these differentially expressed genes have been linked to jasmonic acid signaling before. Our data therefore suggests that Rcr3pim is involved in the regulation of the jasmonic acid-dependent defense responses to damaging plant parasitic nematodes.