Comprehensive Identification of Key Genes Responsible for Leaf Senescence of Rice ( L.) by WGCNA Using Two Independent Aging Datasets.

Leaf senescence is the final stage of plant leaf development, closely related to the yield and quality of cereal crops. However, the molecular regulatory mechanism of rice ( L.) leaf senescence is not yet very clear. This study conducted weighted gene co-expression network analysis (WGCNA) using two independent senescence-related transcriptome datasets of rice. Modules positively/negatively correlated with leaf senescence were obtained for each dataset. The additional intersection analysis screened out 180 and 248 common genes highly and positively/negatively correlated with leaf senescence. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses showed that these identified common genes were mainly enriched in senescence-related biological processes and pathways, such as reactive oxygen metabolism, hormone pathway, cell death regulation, stimulus-response, amino acid metabolism, photosynthetic metabolism, etc. Transcription factors and studied genes were identified from these common genes, finding that transcription regulation, hormone regulation, reactive oxygen species metabolism, and photosynthesis pathways play an essential role in rice leaf senescence. Protein-protein interaction (PPI) network analysis identified 28 key genes probably involved in leaf senescence. Hub network analysis identified 68 hub genes probably participating in leaf senescence. Twelve genes from the PPI network and the hub gene network were selected for RT-qPCR validation of their expression patterns during leaf senescence. The functions of the senescence-correlated genes identified in this study are discussed in detail. These results provide valuable insights into the regulatory mechanisms of leaf senescence in rice and lay a foundation for functional research on candidate senescence genes.