What new progress has been made in research on stress tolerance in soybean?

In earlier research, the research groups led by Zhang Jinsong and Chen Shouyi at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, identified a series of soybean miRNAs. This study found that among these miRNAs, the expression of miR172a is induced by salt stress. Using a soybean hairy root transformation system, the function of miR172a was studied in depth.

The results showed that overexpression in hairy roots significantly enhanced the salt tolerance of soybean. A series of experiments found that miR172a, by cleaving and degrading the target gene SSAC1, relieves the inhibition by its protein of the promoter of the thiamine (vitamin B) precursor synthase gene THI1, thereby promoting THI1 expression, increasing thiamine synthesis, and consequently enhancing soybean salt tolerance. In addition, grafting experiments found that miR172a can act as a long-distance signaling molecule, transported from soybean transgenic hairy roots to the shoot, where it regulates the expression of the target gene and downstream genes.

This research provides an important theoretical basis for revealing the mechanisms of stress tolerance in soybean and improving soybean stress tolerance.