A Effector, BxSCD3, Suppresses Plant Defense and Contributes to Virulence.

is the most economically important species of migratory plant-parasitic nematodes (PPNs) and causes severe damage to forestry in China. The successful infection of relies on the secretion of a repertoire of effector proteins. The effectors, which suppress the host pine immune response, are key to the facilitation of parasitism. An exhaustive list of candidate effectors of was predicted, but not all have been identified and characterized. Here, an effector, named BxSCD3, has been implicated in the suppression of host immunity. BxSCD3 could suppress pathogen-associated molecular patterns (PAMPs) PsXEG1- and INF1-triggered cell death when it was secreted into the intracellular space in was highly up-regulated in the early infection stages of . does not affect reproduction, either at the mycophagous stage or the phytophagous stage, but it contributes to the virulence of Moreover, significantly influenced the relative expression levels of defense-related (PR) genes and in in the early infection stage. These results suggest that BxSCD3 is an important toxic factor and plays a key role in the interaction between and host pine.