Identification of Phaseolus vulgaris SAT genes and their stress-sensitive expression under abiotic stress conditions

Sulfur is vital for plant growth, metabolism, and adaptation to environmental stresses. Cysteine, the first sulfur-containing organic molecule produced in plants, serves as a precursor to many sulfur-based active compounds. The rate-limiting step in the synthesis of these compounds is catalyzed by the serine acetyltransferase (SERAT) enzyme. Beans are among the most widely grown and consumed legumes worldwide, due to their high nutritional value, environmental resilience, and economic value. The aim of this study is to characterize SAT genes in bean using bioinformatics tools. In addition, the effect of bean SAT genes on the response to salt and drought stress has been investigated at the level of gene expression. 6 SAT genes have been identified in beans. The proteins encoded by these genes have an amino acid length of 286–400, a molecular weight of 30.31–43.48 kDa, a theoretical isoelectric point of 6.15–8.95, and are stable. SAT genes were found in the cytoplasm, nucleus, mitochondria, and chloroplasts. Throughout evolution, SAT genes have undergone purifying selection. In the promoter region analysis of SAT genes, 44 distinct cis elements were identified, many of which are stress-related. qRT-PCR analysis showed that the PvSAT2 and PvSAT4 genes were more highly expressed in the sensitive variety under salt and drought stress. All SAT genes are upregulated in the sensitive variety under salt stress. Expression responses to stress suggest that these genes may play a potential role in stress response mechanisms. This study contributes to the identification of candidate genes for future functional studies aimed at validating the current hypothesis.