论文题目: An Arabidopsis homolog of importin β1 is required for ABA response and drought tolerance

论文编号:
作者: Luo, YJ (罗焱杰); Wang, ZJ (王志娟 ); Ji, HT (纪洪涛); Fang, H (方慧); Wang, SF (Wang, Shuangfeng); Tian, LN (田立宁); Li, X (李霞)
刊物名称: PLANT JOURNAL
卷期页码: 卷: 75, 期: 3, 页: 377-389
发表年度: 2013
DOI: http://dx.doi.org/10.1111/tpj.12207
摘要: The import of proteins into the nucleus in response to drought is critical for mediating the reprogramming of gene expression that leads to drought tolerance. However, regulatory mechanisms involved in nuclear protein import remain largely unknown. Here, we have identified an Arabidopsis gene (AtKPNB1) as a homolog of humanKPNB1(importin β1).AtKPNB1was expressed in multiple organs, and the protein was localized in the cytoplasm and nucleus. AtKPNB1 was able to facilitate nuclear import of a model protein. Null mutation ofAtKPNB1delayed development under normal growth conditions and increased sensitivity to abscisic acid (ABA) during seed germination and cotyledon development. Inactivation ofAtKPNB1increased stomatal closure in response to ABA, reduced the rate of water loss, and substantially enhanced drought tolerance. AtKPNB1 interacted with several importin α proteins, nucleoporin AtNUP62, and the Arabidopsis Ran proteins. Inactivation ofAtKPNB1did not affect the ABA responsiveness or the expression level or subcellular localization of ABI1, ABI2 or ABI5, key regulators of the ABA signaling pathway. Moreover, phenotypic analysis of epistasis revealed that AtKPNB1 modulates the ABA response and drought tolerance through a pathway that is independent of ABI1 and ABI5. Collectively, our results show that AtKPNB1 is an Arabidopsis importin β that functions in ABA signaling.