Over-expression of GmSN1 enhances virus resistance in Arabidopsis and soybean.

GmSN1 enhances virus resistance in plants most likely by affecting the expression of signal transduction and immune response genes. Soybean mosaic virus (SMV) infection causes severe symptom and leads to massive yield loss in soybean (Glycine max). By comparative analyzing gene expression in the SMV-resistant soybean cultivar Rsmv1 and the susceptible cultivar Ssmv1 at a transcriptome level, we found that a subgroup of Gibberellic Acid Stimulated Transcript (GAST) genes were down-regulated in SMV inoculated Ssmv1 plants, but not Rsmv1 plants. Sequence alignment and phylogenetic analysis indicated that one of the GAST genes, GmSN1, was closely related to Snakin-1, a well-characterized potato microbial disease resistance gene. When over-expressed in Arabidopsis and soybean, respectively, under the control of the 35S promoter, GmSN1 enhanced turnip mosaic virus resistance in the transgenic Arabidopsis plants, and SMV resistance in the transgenic soybean plants, respectively. Transcriptome analysis results showed that the up-regulated genes in the 35S:GmSN1 transgenic Arabidopsis plants were largely enriched in functional terms including "signal transduction" and "immune response". Real-time PCR assay indicated that the expression of GmAKT2, a potassium channel gene known to enhance SMV resistance when over-expressed in soybean, was elevated in the 35S:GmSN1 transgenic soybean plants. Taken together, our results suggest that GmSN1 enhances virus resistance in plants most likely by affecting the expression of signal transduction and immune response genes.