Bioinformatics Analyses of Serine Acetyltransferase (SAT) Gene Family in Rice (Oryza sativa) and their Expressions under Salt Stress
Abstract Assimilation of sulfur to cysteine occurs in the presence of serine acetyltransferase (SAT). In this study, SAT genes in rice (Oryza sativa) were identified and analyzed using bioinformatics approaches. Also, these genes were tested under salt stress. OsSATs have two common motifs, bacterial transferase hexapeptide and acetyltransferase and underwent purifying selection. They have more similar protein sequences compared to Arabidopsis. However, there is structural and functional divergence among OsSATs which may be driven by the segmental and tandem duplications. Purifying selection and gene duplications may also have effect leading to variation of specificity and selectivity of OsSATs. In this regard, Asp (D), His (H), Gly (G), Thr (T), Arg (R), Ala (A), and Leu (L) are identified as well-conserved residues in their active sites which have an indicator role on their functions. The OsSATs expressions in different tissues, organs and under hormones showed that jasmonic acid was main hormone inducing the expressions of OsSAT1;1, OsSAT2;1, and OsSAT2;2 whereas auxin and abscisic acid only triggered OsSAT1;1 expression. On the other hand, wet-lab expressions of OsSATs in this study indicated that OsSAT1;1, OsSAT1;2 and OsSAT1;3 genes were upregulated under different exposure times of salt stress. OsSAT1;1 is the only OsSAT induced by various situmuli. The findings can be used by plant breeders and genetic engineers to develop new rice varieties having optimal growth and stress tolerance.