Genome wide identification and characterization of MAPK genes reveals their potential in enhancing drought and salt stress tolerance in Gossypium hirsutum

Background: The cotton crop is universally considered as protein and edible oil source besides the major contributor of natural fiber and is grown in tropical and subtropical regions around the world Unpredicted environmental stresses are becoming significant threats to sustainable cotton production, ultimately leading to a substantial irreversible economic loss. Mitogen-activated protein kinase(MAPK) is generally considered essential for recognizing environmental stresses through phosphorylating downstream signal pathways and plays a vital role in numerous biological processes.Results: We have identified 74 MAPK genes across cotton, 41 from G. hirsutum, 19 from G. raimondii, whereas 14 have been identified from G. arboreum. The MAPK gene-proteins have been further studied to determine their physicochemical characteristics and other essential features. In this perspective, characterization, phylogenetic relationship,chromosomal mapping, gene motif, cis-regulatory element, and subcellular localization were carried out. Based on phylogenetic analysis, the MAPK family in cotton is usually categorized as A, B, C, D, and E clade. According to the results of the phylogenic relationship, cotton has more MAPKS genes in Clade A than Clade B. The cis-elements identified were classified into five groups(hormone responsiveness, light responsiveness, stress responsiveness, cellular development, and binding site). The prevalence of such elements across the promoter region of these genes signifies their role in the growth and development of plants. Seven GHMAPK genes(GH＿A07G1527, GH＿D02G1138,GH＿D03G0121, GH＿D03G1517, GH＿D05G1003, GH＿D11G0040, and GH＿D12G2528) were selected, and specific tissue expression and profiling were performed across drought and salt stresses. Results expressed that six genes were upregulated under drought treatment except for GH＿D11G0040 which is downregulated. Whereas all the seven genes have been upregulated at various hours of salt stress treatment.Conclusions: RNA sequence and qPCR results showed that genes as di erentially expressed across both vegetative and reproductive plant parts. Similarly, the qPCR analysis showed that six genes had been upregulated substantially through drought treatment while all the seven genes were upregulated across salt treatments. The results of this study showed that cotton GHMPK3 genes play an important role in improving cotton resistance to drought and salt stresses. MAPKs are thought to play a significant regulatory function in plants’ responses to abiotic stresses according to various studies. MAPKs’ involvement in abiotic stress signaling and innovation is a key goal for crop species research, especially in crop breeding.