Pearl millet is a significant crop that is tolerant to abiotic stresses and is a staple food of arid regions. However, its underlying mechanisms of stress tolerance are not fully understood. Plant survival is regulated by the ability to perceive a stress signal and induce appropriate physiological changes. Here, we screened for genes regulating physiological changes such as chlorophyll content (CC) and relative water content (RWC) in response to abiotic stress by using "weighted gene coexpression network analysis" (WGCNA) and clustering changes in physiological traits, i.e., CC and RWC associated with gene expression. Genes' correlations with traits were defined in the form of modules, and different color names were used to denote a particular module. Modules are groups of genes with similar patterns of expression, which also tend to be functionally related and co-regulated. In WGCNA, the dark green module (7082 genes) showed a significant positive correlation with CC, and the black (1393 genes) module was negatively correlated with CC and RWC. Analysis of the module positively correlated with CC highlighted ribosome synthesis and plant hormone signaling as the most significant pathways. Potassium transporter 8 and monothiol glutaredoxin were reported as the topmost hub genes in the dark green module. In Clust analysis, 2987 genes were found to display a correlation with increasing CC and RWC. Furthermore, the pathway analysis of these clusters identified the ribosome and thermogenesis as positive regulators of RWC and CC, respectively. Our study provides novel insights into the molecular mechanisms regulating CC and RWC in pearl millet.

College of Agriculture and Biotechnology Zhejiang University Hangzhou 310058 China

Department of Adaptive Biotechnology Global Change Research Institute of the Czech Academy of Sciences 60300 Brno Czech Republic

Department of Animal and Food Sciences College of Agriculture Food and Environment University of Kentucky Lexington KY 40546 USA

Plant Molecular Biology and Biotechnology Research Center Gyeongsang National University Jinju Daero Jinju 52828 Gyeongnam do Republic of Korea

Plant Science Department McGill University Macdonald Campus Sainte Anne de Bellevue QC H9X 3V9 Canada

Sequencing and Discovery Genomics Center Stowers Institute for Medical Research Kansas City MO 64110 USA

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