The Alfin-like transcription factor GmAlfin09 regulates endoplasmic reticulum stress in soybean via a peroxidase GmPRDX6

Soybean is a valuable oil crop cultivated throughout the world, but also highly susceptible to environmental stressors. The development of approaches to enhancing soybean stress resistance is thus vital to improving yields. In prior studies, Alfin has been shown to serve as an epigenetic regulator of plant growth and development. No studies of Alfin have yet been reported in soybean, however. In this study, the endoplasmic reticulum (ER) stress- and reactive oxygen species (ROS)-related transcription factor GmAlfin09 was identified. Screening of genes co-expressed with GmAlfin09 unexpectedly led to the identification of the peroxidase GmPRDX6. Further analyses revealed that both GmAlfin09 and GmPRDX6 were responsive to ER stress, with GmPRDX6 localizing to the ER under stress. Promoter binding experiments confirmed the ability of GmAlfin09 to directly bind the GmPRDX6 promoter. When GmAlfin09 and GmPRDX6 were overexpressed in soybean, enhanced ER stress resistance and decreased ROS levels were observed. Together, these findings suggest that GmAlfin09 can promote the upregulation of GmPRDX6, which subsequently localizes to the ER, reduced ROS levels, promotes ER homeostasis, and helps ensure the normal growth of soybean even under ER stress. This study highlights a novel genetic target for the future molecular breeding of stress-resistant soybean cultivars. HIGHLIGHTGmAlfin09 can increase the expression of GmPRDX6 to reduce ROS level under ER stress.