Genome-Wide Analysis of GmMYB S20 Transcription Factors Reveals Their Critical Role in Soybean Nodulation

Soybean relies on symbiotic nitrogen fixation (SNF) to support sustainable agriculture. In this study, we conducted a comprehensive analysis of the GmMYB transcription factor subfamily 20, with a focus on <i>GmMYB62a</i> and <i>GmMYB62b</i>. Phylogenetic and structural analyses revealed that these genes are evolutionarily conserved among legumes and possess distinct domain architectures. Expression profiling and GUS staining showed that <i>GmMYB62a</i> and <i>GmMYB62b</i> are constitutively expressed in nodules. Functional analyses revealed that loss of <i>GmMYB62s</i> function significantly reduced nodule density, while overexpression promoted nodulation. Transcriptomic analysis (RNA-seq) further demonstrated that <i>GmMYB62s</i> regulate key pathways, including hormone signaling, immune responses, and cell wall metabolism, thereby coordinating symbiotic interactions. Collectively, our findings identify <i>GmMYB62a</i> and <i>GmMYB62b</i> as critical molecular regulators of nodulation in soybean, providing promising targets for improving symbiotic nitrogen fixation efficiency in legume crops.