The Gma-miR394a/GmFBX176 module is involved in regulating the soybean (Glycine max L.) response to drought stress.

Drought seriously affects the yield and quality of soybean. Previous studies have shown that the gma-miR394a/GmFBX176 module regulates the response of Arabidopsis to drought stress. However, whether the gma-miR394a/GmFBX176 module is involved in the regulation of the soybean drought stress response remains unclear. Here, the function of the gma-miR394a/GmFBX176 module in the soybean drought stress response was evaluated. In soybean hairy roots, drought stress induced the transcription of gma-miR394a and inhibited the transcription of GmFBX176. GUS histochemical staining showed that transgenic GmFBX176p:GUS soybean hairy root staining was weak and that GUS transcript levels decreased under drought stress. A transient expression experiment in tobacco showed that gma-miR394a inhibited GmFBX176 transcription. Under drought stress, composite soybean plants overexpressing gma-miR394a showed increased drought resistance compared with control K599 composite soybean plants (K599); their survival rate and peroxidase activity were higher than those of K599, and their malondialdehyde content was lower. In contrast, composite soybean plants overexpressing GmFBX176m3 (gma-miR394a complement site mutation) presented lower drought resistance than K599 plants. Transcriptomic sequencing showed that the gma-miR394a/GmFBX176 module affected the transcript levels of stress response genes and transcription factors. These results indicate that the gma-miR394a/GmFBX176 module can be used to improve the drought resistance of soybean.