Genome-wide identification of WRKY genes in soybean and functional analysis of GmWRKY162-GmGSL7c in resistance to soybean mosaic virus

Abstract

Abstract Background Soybean mosaic disease caused by soybean mosaic virus (SMV) is one of the most devastating and widespread diseases in soybean producing areas worldwide. The WRKY transcription factors (TFs) are widely involved in plant development and stress responses. However, the roles of GmWRKY TFs in resistance to SMV infection are largely unclear.Results Here, a total of 185 GmWRKYs were identified from soybean (Glycine max), and were clustered into 3 groups and 7 subgroups. The characteristics, such as gene structure, conserved motifs, cis-regulatory elements, and selective pressure, were systematically analyzed. Furthermore, 60 GmWRKY genes were differentially expressed during SMV infection according to the transcriptome data. Among these genes, the expression of GmWRKY162 decreased after imidazole treatment in the incompatibility combination in soybean varieties Jidou 7 with SMV strain N3, which was confirmed by RT‒qPCR. Remarkably, the silencing of GmWRKY162 reduced callose deposition and enhanced virus spread during SMV infection. Next, EMSA and ChIP‒qPCR revealed that GmWRKY162 could directly bind to the promoter of GmGSL7c, which was reported to be involved in callose synthesis in our previous study.Conclusion Our study revealed that GmWRKY162 play a positive role in increasing callose deposition and suppressing virus spread during SMV infection by targeting GmGSL7c, which providing valuable insights into the roles of WRKY family genes in response to SMV and guidance for future studies in understanding virus-resistance mechanisms in soybean.