GmWRKY31 and GmHDL56 Enhances Resistance to by Regulating Defense-Related Gene Expression in Soybean.

Phytophthora root and stem rot of soybean [ (L.) Merr.] caused by the oomycete , is a destructive disease worldwide. The molecular mechanism of the soybean response to is largely unclear. We report a novel WRKY transcription factor (TF) in soybean, GmWRKY31, in the host response to . Overexpression and RNA interference analysis demonstrated that GmWRKY31 enhanced resistance to in transgenic soybean plants. GmWRKY31 was targeted to the nucleus, where it bound to the W-box and acted as an activator of gene transcription. Moreover, we determined that GmWRKY31 physically interacted with GmHDL56, which improved resistance to in transgenic soybean roots. GmWRKY31 and GmHDL56 shared a common target which was induced by . Overexpression and RNA interference analysis demonstrated that enhanced resistance to in transgenic soybean plants. Several pathogenesis-related () genes were constitutively activated, including , , , , , and , in soybean plants overexpressing transcripts. By contrast, the induction of genes was compromised in transgenic -RNAi lines. Taken together, these findings suggested that the interaction between GmWRKY31 and GmHDL56 enhances resistance to by regulating defense-related gene expression in soybean.