SOS1, SERK1 and WEE1, Confer a Defence Response to Salt Stress with Increasing NaCl in Alfalfa (Medicago Sativa L.) Callus

Abstract Alfalfa is an important forage that contributes wildlife habitat and soil conservation worldwide and has a high nutritional feeding quality and N fixation potential. However, alfalfa production is seriously reduced by abiotic stress factors. In this study, SOS1 ,SERK1, WEE1 genes were expressed in alfalfa callus cells to control NaCl stress under in vitro conditions. The important callus traits in terms of NaCl resistance were found among the genotypes. Higher sugar contents were accumulated in tested genotypes than in control callus when all were exposed to NaCl stress. Based on proline assay, there were inverse relationships between NaCl acclimated-callus and tested genotypes. Na+ and K+ showed an increasing trend in response to the increasing concentration of NaCl. The results showed that callus growth increased salt stress related gene expression. SOS1, SERK1 and WEE1 gene expression levels peaked at 50 mM while highest Na+ and K+ and sugar content happened at 110 mM NaCl. As a result of flow cytometry analysis, there were often endopolyploidy in the tested genotypes. Our findings indicated that the SOS1, SERK1 and WEE1 genes was effective in promoting the alfalfa callus cells in response to salt stress induced by NaCl.