Transcription factor WRKY46 regulates osmotic stress responses and stomatal movement independently in Arabidopsis.
Drought and salt stress severely inhibit plant growth and development; however, the regulatory mechanisms of plants in response to these stresses are not fully understood. Here we report that the expression of a WRKY transcription factor WRKY46 is rapidly induced by drought, salt and oxidative stresses. T-DNA insertion of WRKY46 leads to more sensitivity to drought and salt stress, whereas overexpression of WRKY46 (OV46) results in hypersensitivity in soil-grown plants, with a higher water loss rate, but with increased tolerance on the sealed agar plates. Stomatal closing in the OV46 line is insensitive to ABA because of a reduced accumulation of reactive oxygen species (ROS) in the guard cells. We further find that WRKY46 is expressed in guard cells, where its expression is not affected by dehydration, and is involved in light-dependent stomatal opening. Microarray analysis reveals that WRKY46 regulates a set of genes involved in cellular osmoprotection and redox homeostasis under dehydration stress, which is confirmed by ROS and malondialdehyde (MDA) levels in stressed seedlings. Moreover, WRKY46 modulates light-dependent starch metabolism in guard cells via regulating QUA-QUINE STARCH (QQS) gene expression. Taken together, we demonstrate that WRKY46 plays dual roles in regulating plant responses to drought and salt stress and light-dependent stomatal opening in guard cells.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
Zhong Jie
ZJ
Ding
Jing Ying
JY
Yan
Xiao Yan
XY
Xu
Di Qiu
DQ
Yu
Gui Xin
GX
Li
Shu Qun
SQ
Zhang
Shao Jian
SJ
Zheng
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D008027:Light; D008315:Malondialdehyde / Q000378:metabolism; D016254:Mutagenesis, Insertional; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010641:Phenotype; D054046:Plant Stomata / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism; D012492:Salts; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D013213:Starch / Q000378:metabolism; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; D012492:Salts; D014157:Transcription Factors; C579612:WRKY46 protein, Arabidopsis; D008315:Malondialdehyde; D013213:Starch
Arabidopsis; WRKY46; drought; salt stress; stomatal movement; transcription factor