The gma-miR164a/GmNAC115 module participates in the adaptation of soybean to drought and salt stress by influencing reactive oxygen species scavenging

The regulatory modules formed by microRNAs and transcription factors (TFs) play important roles in plant stress responses and adaptations. However, the function and molecular mechanism of the gma-miR164a/GmNAC115 module in soybean responses to drought and salt stress remain unclear. This study revealed that the soybean gma-miR164a/GmNAC115 module is involved in the response to abiotic stress. Analysis of salt and drought tolerance in soybean hairy roots and transgenic Arabidopsis revealed that gma-miR164a plays a negative regulatory role in drought and salt stress responses, whereas its target GmNAC115 positively regulates plant tolerance to these stressors. DNA affinity purification sequencing was used to identify downstream target genes of the TF GmNAC115 in the whole genome. GmNAC115 could activate the expression of the downstream target genes GmWRKY21, GmAPX6, and GmPOD25 by binding to NAC recognition sequence cis-acting elements in their promoters. Moreover, GmWRKY21, GmAPX6, and GmPOD25 play positive roles in the adaptation of soybean to drought and salt stress. In addition, GmWRKY21 positively regulates GmAPX6 and GmPOD25 expression by binding W-box cis-acting elements. In summary, these results suggest that the gma-miR164a/GmNAC115 module maintains cell reduction/oxidation homeostasis by removing reactive oxygen species, thereby improving soybean tolerance to drought and salt stress.