Negative control of Strictisidine synthase like-7 gene on salt stress resistance in Arabidopsis thaliana

Strictosidine synthase-like (SSL) is a group of gene families in the Arabidopsis genome, which whose orthologues in other plants are key enzymes in mono-terpenoid indole-alkaloid biosynthesis pathway. The SSL7 is upregulated upon treatments of Arabidopsis plants with signaling molecules such as SA, methyl jasmonate and ethylene. To find the functional role of the gene, a T-DNA-mediated knockout mutant (ssl7) along with the wildt ype were treated with different concentrations of NaCl. The expression level of salt stress genes including P5CS1, NCED3, AAO3 and RD29A at 150 mM NaCl demonstrated that the expression was significantly higher in ssl7 compared with the expression in Col-0. The activities of Catalase (CAT), Ascorbate Peroxidase (APX), Peroxidase (POD) and Superoxide Dismutase (SOD) were measured in different concentrations of NaCl. The results suggested that the enzymes activities were significantly higher in ssl7 compared with wild-type Col-0. In total, the results suggest that SSL7 might have a salicylic acid-dependent negative regulatory role in plant resistance to salt stress.