WRKY41 controls Arabidopsis seed dormancy via direct regulation of ABI3 transcript levels not downstream of ABA. (28th July 2014)

• Record Type: Journal Article
• Authors: Ding, Zhong Jie; Yan, Jing Ying; Li, Gui Xin; Wu, Zhong Chang; Zhang, Shu Qun; Zheng, Shao Jian
• Is Part Of: Plant journal. Volume 79:Number 5(2014:Sep.)
• Page Start: 810
• Page End: 823
• Publication Date: 2014-07-28
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12597
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12597-abs-0001"> <title>Summary</title> <p>Although seed dormancy is an important agronomic trait, its molecular basis is poorly understood. ABSCISIC ACID INSENSITIVE 3 (ABI3) plays an essential role in the establishment of seed dormancy. Here, we show that the lack of a seed‐expressed WRKY transcription factor, WRKY41, confers reduced primary seed dormancy and thermoinhibition, phenotypes resembling those for a lack of ABI3. Loss‐of‐function <italic>abi3‐17</italic> and <italic>wrky41</italic> alleles also both confer reduced sensitivity to ABA during germination and early seedling growth. Absence of WRKY41 decreases <italic>ABI3</italic> transcript abundance in maturing and imbibed seeds, whereas transgenically overexpressing WRKY41 increases <italic>ABI3</italic> expression. Moreover, transgenic overexpression of <italic>ABI3</italic> completely restores seed dormancy phenotypes on <italic>wrky41</italic>. ChIP‐qPCR and EMSA reveal that WRKY41 binds directly to the <italic>ABI3</italic> promoter through three adjacent W–boxes, and a transactivation assay indicates that these W–boxes are essential for <italic>ABI3</italic> expression. Whilst RT‐qPCR analysis shows that the regulation of <italic>ABI3</italic> by WRKY41 is not through ABA and other factors known to promote <italic>ABI3</italic> transcription during seed maturation and germination, we also show that high concentrations of ABA might promote negative feedback regulation of <italic>WRKY41</italic> expression. Finally, analysis of the <italic>wrky41 aba2</italic> double mutant confirms that WRKY41 and ABA collaboratively regulate <italic>ABI3</italic> expression and seed dormancy. In summary, our results demonstrate that WRKY41 is an important regulator of <italic>ABI3</italic> expression, and hence of seed dormancy.</p> </abstract>