Expression pattern of GmLAX genes under different stresses in soybean drought sensitive cultivar and tolerant cultivar

Auxin has been reported to regulate plant growth and development, as well as to mediate plant adaption to abiotic stresses, including drought. AUX/LAX family displays auxin uptake functions and comprises four highly conserved genes AUX1 and LIKE AUX1 (LAX1, LAX2, and LAX3) in Arabidopsis. There are fifteen GmLAX family genes in the soybean genomes and several members were regulated by dehydration stress. In this study, the sequence differences and expression pattern of GmLAXs-I were analyzed under stress treatment between the soybean drought-tolerant Jindou 21 and drought-sensitive varieties Zhongdou 33. Five homologous genes of AUX1 were all responsive to PEG, salt, ABA and IAA stimuli. There were two SNPs in the promoter region of GmLAX4 gene, and this gene was differentially expressed in two cultivars. Moreover, our results showed YFP-GmLAXs are predominantly localized in plasma membrane. Taken together, our results suggest that GmLAXs are involved in abiotic response, which can provide theoretical and technical support for the genetic improvement of soybean drought tolerance.