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Transcription factor WRKY 22 promotes aluminum tolerance via activation of Os FRDL 4 expression and enhancement of citrate secretion in rice ( Oryza sativa )
Author(s) -
Li Ge Zi,
Wang Zhan Qi,
Yokosho Kengo,
Ding Bing,
Fan Wei,
Gong Qiao Qiao,
Li Gui Xin,
Wu Yun Rong,
Yang Jian Li,
Ma Jian Feng,
Zheng Shao Jian
Publication year - 2018
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15143
Subject(s) - wrky protein domain , transcription factor , biology , mutant , oryza sativa , complementation , microbiology and biotechnology , gene , arabidopsis , genetics
Summary Whilst WRKY transcription factors are known to be involved in diverse plant responses to biotic stresses, their involvement in abiotic stress tolerance is poorly understood. Os FRDL 4 , encoding a citrate transporter, has been reported to be regulated by ALUMINUM (Al) RESISTANCE TRANSCRIPTION FACTOR 1 ( ART 1) in rice, but whether it is also regulated by other transcription factors is unknown. We define the role of Os WRKY 22 in response to Al stress in rice by using mutation and transgenic complementation assays, and characterize the regulation of Os FRDL 4 by Os WRKY 22 via yeas one‐hybrid, electrophoretic mobility shift assay and Ch IP ‐quantitative PCR. We demonstrate that loss of Os WRKY 22 function conferred by the oswrky22 T‐ DNA insertion allele causes enhanced sensitivity to Al stress, and a reduction in Al‐induced citrate secretion. We next show that Os WRKY 22 is localized in the nucleus, functions as a transcriptional activator and is able to bind to the promoter of Os FRDL 4 via W‐box elements. Finally, we find that both Os FRDL 4 expression and Al‐induced citrate secretion are significantly lower in art1 oswrky22 double mutants than in the respective single mutants. We conclude that Os WRKY 22 promotes Al‐induced increases in Os FRDL 4 expression, thus enhancing Al‐induced citrate secretion and Al tolerance in rice.