The leaf senescence-promoting transcription factor AtNAP activates its direct target gene CYTOKININ OXIDASE 3 to facilitate senescence processes by degrading cytokinins  

作　　者：Youzhen Hu Bin Liu Huazhong Ren Liping Chen Christopher B.Watkins Su-Sheng Gan 

机构地区：[1]Plant Biology Section,School of Integrative Plant Science,Cornell University,Ithaca,New York 14853,USA [2]Current address:College of Food Science,Shihezi University,Xinjiang 832000,China [3]College of Horticulture,China Agriculture University,Beijing 100193,China [4]Current address:Department of Plant Genomics,Centre for Research in Agricultural Genomics(CRAG),CSIC-IRTA-UAB-UB,Bellaterra,Spain [5]College of Agriculture and Biotechnology,Zhejiang University,Hangzhou 310058,China [6]Horticulture Section,School of Integrative Plant Science,Cornell University,Ithaca,New York 14853,USA

出　　处：《Molecular Horticulture》2021年第1期60-71,共12页分子园艺（英文）

基　　金：The work was supported by Cornell University.Y.H.and B.L.were funded by scholarships from China Scholars Council.

摘　　要：Cytokinins(CKs)are a class of adenine-derived plant hormones that plays pervasive roles in plant growth and development including cell division,morphogenesis,lateral bud outgrowth,leaf expansion and senescence.CKs as a“fountain of youth”prolongs leaf longevity by inhibiting leaf senescence,and therefore must be catabolized for senescence to occur.AtNAP,a senescence-specific transcription factor has a key role in promoting leaf senescence.The role of AtNAP in regulating CK catabolism is unknown.Here we report the identification and characterization of AtNAP-AtCKX3(cytokinin oxidase 3)module by which CKs are catabolized during leaf senescence in Arabidopsis.Like AtNAP,AtCKX3 is highly upregulated during leaf senescence.When AtNAP is chemically induced AtCKX3 is co-induced;and when AtNAP is knocked out,the expression of AtCKX3 is abolished.AtNAP physically binds to the cis element of the AtCKX3 promoter to direct its expression as revealed by yeast one-hybrid assays and in planta experiments.Leaves of the atckx3 knockout lines have higher CK concentrations and a delayed senescence phenotype compared with those of WT.In contrast,leaves with inducible expression of AtCKX3 have lower CK concentrations and exhibit a precocious senescence phenotype compared with WT.This research reveals that AtNAP transcription factor˗AtCKX3 module regulates leaf senescence by connecting two antagonist plant hormones abscisic acid and CKs.

关 键 词：ABA ABA-cytokinin crosstalk Aging ARABIDOPSIS Cytokinin metabolism Leaf longevity Plant hormone Senescence-associated genes(SAGs) 

分 类 号：G63[文化科学—教育学]