title: JAZ7 negatively regulates dark-induced leaf senescence in Arabidopsis.
abstract: JASMONATE ZIM-domain (JAZ) proteins play important roles in plant defence and growth by regulating jasmonate signalling. Through data mining, we discovered that the JAZ7 gene was up-regulated in darkness. In the dark, the jaz7 mutant displayed more severe leaf yellowing, quicker chlorophyll degradation, and higher hydrogen peroxide accumulation compared with wild-type (WT) plants. The mutant phenotype of dark-induced leaf senescence could be rescued in the JAZ7-complemented and -overexpression lines. Moreover, the double mutants of jaz7 myc2 and jaz7 coi1 exhibited delayed leaf senescence. We further employed GeneChip analysis to study the molecular mechanism. Some key genes down-regulated in the triple mutant myc2 myc3 myc4 were up-regulated in the jaz7 mutant under darkness. The Gene Ontology terms 'leaf senescence' and 'cell death' were significantly enriched in the differentially expressed genes. Combining the genetic and transcriptomic analyses together, we proposed a model whereby darkness can induce JAZ7, which might further block MYC2 to suppress dark-induced leaf senescence. In darkness, the mutation of JAZ7 might partially liberate MYC2/MYC3/MYC4 from suppression, leading the MYC proteins to bind to the G-box/G-box-like motifs in the promoters, resulting in the up-regulation of the downstream genes related to indole-glucosinolate biosynthesis, sulphate metabolism, callose deposition, and JA-mediated signalling pathways. In summary, our genetic and transcriptomic studies established the JAZ7 protein as an important regulator in dark-induced leaf senescence.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Di
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Qunlian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Kang
authors.initials: K
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Chunchao
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: You
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Susie Y
authors.initials: SY
authors.lastname: Dai
authors.affiliation: Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA zhensu@cau.edu.cn x_wenying@yahoo.com syuan@neo.tamu.edu.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China zhensu@cau.edu.cn x_wenying@yahoo.com syuan@neo.tamu.edu.
authors.forename: Wenying
authors.initials: W
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, PR China zhensu@cau.edu.cn x_wenying@yahoo.com syuan@neo.tamu.edu.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Su
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism; D003624:Darkness; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding / Q000187:drug effects; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D059467:Transcriptome / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C112279:COI1 protein, Arabidopsis; C000602233:JAZ7 protein, Arabidopsis; C473611:MYC2 protein, Arabidopsis; D012097:Repressor Proteins; D006861:Hydrogen Peroxide
keywords: Arabidopsis; AtJAZ7; COI1; MYC2; dark-induced leaf senescence; transcriptomics.