Comparative transcriptome analysis revealed regulatory and pivotal genes under drought stress in soybean

Soybean is an important oil and protein crop for both food and forage, and drought can seriously affect its growth and development. Currently, the research on the molecular regulatory mechanisms of drought tolerance in soybeans is still incomplete. In this study, two soybean varieties, Jindou 21 (JD21) with drought-resistant, Suinong 26 (SN26) with drought-sensitive, were as the research objects and treated with 15% PEG6000. Root and leaf at 0 h, 6 h, 12 h after treatment were used to identify physological indicators and RNA-seq. The results showed that the malondialdehyde (MDA) content of JD21 was lower than that of SN26, while the contents of soluble sugar and proline were higher than those of SN26. At 6 h and 12 h after treatment, 5,009 and 7,405 differentially expressed genes (DEGs) were identified in the roots of cultivars SN26 and JD21, respectively. Correspondingly, 5,077 and 6,732 DEGs were detected in the leaves of the same cultivars at these time points. Furthermore, 2,603 and 3,128 DEGs were commonly differentially expressed in both roots and leaves of SN26 and JD21, respectively. KEGG enrichment analysis showed that DEGs were significantly enriched in glutathione metabolism pathway, arginine and proline metabolism pathway, glycolysis/gluconeogenesis pathway, and starch and sucrose metabolism pathway. In this pathway, the function of GmGST, GmAMD1, GmADH1, GmENO, GmsacA, and GmSUS3 were identified thought transgenic hairy root, which play positive regulatory roles in osmotic stress tolerance. This study provides useful data for researching plant drought responses and offers theoretical support for plant drought-resistant breeding.