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Mol. Cells 2011; 31(4): 303-313

Published online April 30, 2011

https://doi.org/10.1007/s10059-011-0047-1

© The Korean Society for Molecular and Cellular Biology

WRKY22 Transcription Factor Mediates Dark-Induced Leaf Senescence in Arabidopsis

Xiang Zhou, Yanjuan Jiang1,2, and Diqiu Yu*

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China, 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China, 2Graduate University of Chinese Academy of Sciences, Beijing 100039, China

Correspondence to : *Correspondence: ydq@xtbg.ac.cn

Received: June 23, 2011; Revised: January 19, 2011; Accepted: January 21, 2011

Abstract

Arabidopsis WRKY proteins are plant-specific transcrip-tion factors, encoded by a large gene family, which contain the highly conserved amino acid sequence WRKYGQK and the zinc-finger-like motifs, Cys2His2 or Cys2HisCys. They can recognize and bind the TTGAC(C/T) W-box cis-elements found in the promoters of target genes, and are involved in the regulation of gene expression during pathogen defense, wounding, trichome development, and senescence. Here we investigated the physiological function of the Arabidopsis WRKY22 transcription factor during dark-induced senescence. WRKY22 transcription was suppressed by light and promoted by darkness. In addi-tion, AtWRKY22 expression was markedly induced by H2O2. These results indicated that AtWRKY22 was involved in signal pathways in response to abiotic stress. Dark-treated AtWRKY22 over-expression and knockout lines showed accelerated and delayed senescence phenotypes, respectively, and senescence-associated genes exhibited increased and decreased expression levels. Mutual regulation existed between AtWRKY22 and AtWRKY6, AtWR-KY53, and AtWRKY70, respectively. Moreover, AtWRKY22 could influence their relative expression levels by feedback regulation or by other, as yet unknown mechanisms in response to dark. These results prove that AtWRKY22 participates in the dark-induced senescence signal transduction pathway.

Keywords abiotic stress, AtWRKY22, dark, senescence

Article

Research Article

Mol. Cells 2011; 31(4): 303-313

Published online April 30, 2011 https://doi.org/10.1007/s10059-011-0047-1

Copyright © The Korean Society for Molecular and Cellular Biology.

WRKY22 Transcription Factor Mediates Dark-Induced Leaf Senescence in Arabidopsis

Xiang Zhou, Yanjuan Jiang1,2, and Diqiu Yu*

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China, 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China, 2Graduate University of Chinese Academy of Sciences, Beijing 100039, China

Correspondence to:*Correspondence: ydq@xtbg.ac.cn

Received: June 23, 2011; Revised: January 19, 2011; Accepted: January 21, 2011

Abstract

Arabidopsis WRKY proteins are plant-specific transcrip-tion factors, encoded by a large gene family, which contain the highly conserved amino acid sequence WRKYGQK and the zinc-finger-like motifs, Cys2His2 or Cys2HisCys. They can recognize and bind the TTGAC(C/T) W-box cis-elements found in the promoters of target genes, and are involved in the regulation of gene expression during pathogen defense, wounding, trichome development, and senescence. Here we investigated the physiological function of the Arabidopsis WRKY22 transcription factor during dark-induced senescence. WRKY22 transcription was suppressed by light and promoted by darkness. In addi-tion, AtWRKY22 expression was markedly induced by H2O2. These results indicated that AtWRKY22 was involved in signal pathways in response to abiotic stress. Dark-treated AtWRKY22 over-expression and knockout lines showed accelerated and delayed senescence phenotypes, respectively, and senescence-associated genes exhibited increased and decreased expression levels. Mutual regulation existed between AtWRKY22 and AtWRKY6, AtWR-KY53, and AtWRKY70, respectively. Moreover, AtWRKY22 could influence their relative expression levels by feedback regulation or by other, as yet unknown mechanisms in response to dark. These results prove that AtWRKY22 participates in the dark-induced senescence signal transduction pathway.

Keywords: abiotic stress, AtWRKY22, dark, senescence

Mol. Cells
Sep 30, 2022 Vol.45 No.9, pp. 603~672
COVER PICTURE
The Target of Rapamycin Complex (TORC) is a central regulatory hub in eukaryotes, which is well conserved in diverse plant species, including tomato (Solanum lycopersicum). Inhibition of TORC genes (SlTOR, SlLST8, and SlRAPTOR) by VIGS (virus-induced gene silencing) results in early fruit ripening in tomato. The red/ orange tomatoes are early-ripened TORC-silenced fruits, while the green tomato is a control fruit. Top, left, control fruit (TRV2-myc); top, right, TRV2-SlLST8; bottom, left, TRV2-SlTOR; bottom, right, TRV2-SlRAPTOR(Choi et al., pp. 660-672).

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