A Putative Common Bean Chalcone O-Methyltransferase Improves Salt Tolerance in Transgenic Arabidopsis thaliana

Resolving the mechanism of salt stress tolerance in plants becomes a necessity to eventually develop salt-tolerant varieties by determining the key players in tolerance mechanism. Our previous results on transcriptome analysis of common bean under salt stress have revealed an upregulation in a putative chalconeO-methyltransferase (pvChOMT) transcript. In the present study, overexpression of pvChOMT gene in Arabidopsis transgenic lines enhanced salt tolerance. In turn, transgenic plants presented enhanced root growth, better water content, better mass preservation with osmoprotectant accumulation, and higher germination rates in saline conditions. Alignment analysis and predicted structure of pvChOMT have implicated it as the homologue of Medicago sativa chalcone O-methyltransferase (1FP1) with same substrate specificity. Promotor analysis of pvChOMT has shown a TATA box at - 145 position putative cis-acting elements within 1.5-kb upstream of the gene known to be activated through ABA-dependent and ABA-independent manner. Our results suggest that pvChOMT can be a good candidate gene to improve crops for salt stress tolerance.