A Comprehensive Meta-analysis to Identify the Responsive Genes in Sorghum Under Salinity and Drought Stresses (Sorghum bicolor)

Sorghum ( Sorghum bicolor L. Moench) is one of the most significant cereals worldwide. Its growth and yield are threatened by different abiotic stresses, particularly drought and salinity. In this study, we performed a comprehensive meta-analysis on sorghum using RNA-seq data to discover differentially expressed genes effective in responses to drought and salinity stresses. The meta-analysis identified 2139 and 2238 genes for drought, and salinity stresses significantly differentially expressed in control and stress conditions, respectively. Also, the 1835 genes were common under drought and salinity stress conditions. Gene ontology and Kyoto encyclopedia of genes and genomes pathway enrichment analysis showed that differentially expressed genes are significantly enriched in photosynthesis and metabolic pathways, response to abiotic stimulus, phosphorus metabolic process, and biosynthesis of secondary metabolites. We found 96 transcription factor genes, all classified into 28 transcription factor families. Also, 217 protein kinase genes were recognized, with the plant receptor-like kinase (RLK-Pelle) family as the largest category. Besides, the promoter analysis identified 68 significant cis-acting elements in the hub gene's upstream regions. Known cis-acting elements participate in light-responsive, hormone-responsive, stress-related, tissue and development-related, and promoter and site-binding-related elements. Weighted gene co-expression network analysis identified 11 and 6 distinct co-expression modules for drought and salinity stresses, respectively, mainly associated with genes in response to temperature stimulus, photosynthesis, phosphorus metabolic process, and abscisic acid. The network analysis also identified hub genes, including SORBI_3001G410100 , SORBI_3002G343500 , SORBI_3001G426900 , SORBI_3010G246000 , and SORBI_3004G293500 involved in regulating the stress response. These findings provide novel insights into the abiotic stress molecular response and introduce numerous candidate genes, offering evidence for subsequent analysis of validation of their biological functions to unravel the molecular mechanisms of abiotic tolerance in sorghum.