Genome-Wide Identification and Analysis of the Transcription Factor Family Associated with Leaf Senescence in Alfalfa.

Leaves are the most significant parts of forage crops such as alfalfa. Senescence is the terminal stage of leaf development and is controlled by an integrated myriad of endogenous signals and environmental stimuli. WRKY transcription factors (TFs) play essential roles in regulating leaf senescence; however, only a few studies on the analysis and identification of the TF family in have been reported. In this study, we identified 198 family members from the alfalfa ( L.) cultivar 'XinjiangDaye' using phylogenetic analysis and categorized them into three subfamilies, Groups I, II, and III, based on their structural characteristics. Group II members were further divided into five subclasses. In addition, several hormone- and stress-related cis-acting elements were identified in the promoter regions of . Furthermore, 14 aging-related genes from a previous transcriptome in our laboratory were selected for RT-qPCR validation of their expression patterns, and subsequently cloned for overexpression examination. Finally, , , , and were confirmed to cause leaf yellowing in using a transient expression system. Our findings lay a groundwork for further studies on the mechanism of leaf aging and for the creation of new germplasm resources.