Genome-Wide Identification and Analysis of the <i>WRKY</i> Transcription Factor Family Associated with Leaf Senescence in Alfalfa
Xiaojing Peng,
Jinning Hu,
Xiangxue Duan,
Maofeng Chai,
Jiangqi Wen,
Zengyu Wang,
Hongli Xie
Affiliations
Xiaojing Peng
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
Jinning Hu
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
Xiangxue Duan
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
Maofeng Chai
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
Jiangqi Wen
Institute for Agricultural Biosciences, Oklahoma State University, Ardmore, OK 73401, USA
Zengyu Wang
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
Hongli Xie
Shandong Key Laboratory for Germplasm Innovation of Saline-Alkaline Tolerant Grasses and Trees, Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
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 WRKY TF family in Medicago Sativa have been reported. In this study, we identified 198 WRKY family members from the alfalfa (M. sativa 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 MsWRKYs. Furthermore, 14 aging-related MsWRKYs 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, MsWRKY5, MsWRKY66, MsWRKY92, and MsWRKY141 were confirmed to cause leaf yellowing in Nicotiana benthaminana using a transient expression system. Our findings lay a groundwork for further studies on the mechanism of M. sativa leaf aging and for the creation of new germplasm resources.
