阿拉伯芥WRKY63在鹽逆境及開花時間調控的功能性分析

Abstract

WRKY轉錄因子在植物界中是一個很大的蛋白家族。在先前的研究當中，阿拉伯芥WRKY轉錄因子被報導在生物性防禦反應中扮演十分重要的角色，但在非生物逆境與植物生長發育的調控中的作用所知仍然較少。在本研究中我們發現屬於IIIa類的WRKY轉錄因子WRKY63蛋白會和RPD3類的組蛋白去乙酰化酶HDA6有交互作用，我們也觀察到WRKY63的突變株abo3對鹽逆境及離層酸有敏感的表型，並且發現WRKY63和HDA6的雙突變株abo3/axe1-5對鹽逆境會有較單突變更敏感的表型；另外，我們也觀察到abo3突變株有比野生型早開花的表型。透過檢測這些突變株與野生型植株中的基因表達，我們發現鹽逆境反應與開花調控的下游基因表達，相對於野生型在突變株中皆有受到影響。從這些結果我們可以知道WRKY63可能會藉由調控下游基因的表達來影響鹽逆境反應及開花時間的控制。

WRKY transcription factors constitute a large protein family in plants. Previous studies indicated that WRKY transcription factors play important roles in the regulation of gene expression associated with plant defense responses, but the role of WRKY proteins in abiotic stress responses and development is still unclear. In this study, we show that WRKY63, a member of WRKY IIIa subfamily, could interact with the RPD3-like histone deacetylase HDA6. The WRKY63 T-DNA insertion knock-out mutant, abo3, is hypersensitive to ABA and salt stress. Furthermore, abo3/axe1-5 double mutant plants displayed increased salt sensitivity compared with abo3 and axe1-5 plants. In addition, the abo3 mutant showed the early flowering phenotype compared with wild type plants. The expression levels of salt stress-responsive genes as well as genes involved in flowering time control were changed in the abo3 mutants. These data suggested that WRKY63 plays an important role in the regulation of gene expression involved in salt stress responses and flowering time control.