The single-stranded DNA-binding protein WHIRLY1 represses WRKY53 expression and delays leaf senescence in a developmental stage-dependent manner in Arabidopsis.
Leaf senescence in plants involves both positive and negative transcriptional regulation. In this work, we show evidence for the single-stranded DNA-binding protein WHIRLY1 (WHY1) that functions as an upstream suppressor of WRKY53 in a developmental stage-dependent manner during leaf senescence in Arabidopsis (Arabidopsis thaliana). The why1 mutant displayed an early-senescence phenotype. In this background, the expression levels of both WRKY53 and the senescence-associated protease gene SAG12 increased. WHY1 bound to the sequence region that contains an elicitor response element motif-like sequence, GNNNAAATT, plus an AT-rich telomeric repeat-like sequence in the WRKY53 promoter in in vivo and in vitro mutagenesis assays as well as in a chromatin immunoprecipitation assay. This binding to the promoter of WRKY53 was regulated in a developmental stage-dependent manner, as verified by chromatin immunoprecipitation-polymerase chain reaction assay. This direct interaction was further determined by a transient expression assay in which WHY1 repressed β-GLUCURONIDASE gene expression driven by the WRKY53 promoter. Genetic analysis of double mutant transgenic plants revealed that WHY1 overexpression in the wrky53 mutant (oeWHY1wrky53) had no effect on the stay-green phenotype of the wrky53 mutant, while a WHY1 knockout mutant in the wrky53 mutant background (why1wrky53) generated subtle change in the leaf yellow/green phenotype. These results suggest that WHY1 was an upstream regulator of WRKY53 during leaf senescence.
Center for Molecular Cell and Systems Biology, College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350003, China.
Ying
Y
Miao
Jingjing
J
Jiang
Yujun
Y
Ren
Ziwei
Z
Zhao
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D047369:Chromatin Immunoprecipitation; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005966:Glucuronidase / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism
D029681:Arabidopsis Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C496136:WRKY53 protein, Arabidopsis; C503333:Whirly1 protein, Arabidopsis; D005966:Glucuronidase