INDUCER OF CBF EXPRESSION 1 is a male fertility regulator impacting anther dehydration in Arabidopsis

First author: Donghui Wei; Affiliations: Fudan University (复旦大学): Shanghai, China

Corresponding author: Juan Lin 

INDUCER OF CBF EXPRESSION 1 (ICE1) encodes a MYC-like basic helix-loop-helix (bHLH) transcription factor playing a critical role in plant responses to chilling and freezing stresses and leaf stomata (气孔) development. However, no information connecting ICE1 and reproductive development has been reported. In this study, we show that ICE1 controls plant male fertility via impacting anther dehydration (脱水). The loss-of-function mutation in ICE1 gene in Arabidopsis caused anther indehiscence (不裂开) and decreased pollen viability (花粉活力) as well as germination rate (萌发率). Further analysis revealed that the anthers in the mutant of ICE1 (ice1-2) had the structure of stomium (裂缝), though the epidermis (表皮) did not shrink (皱缩) to dehisce. The anther indehiscence and influenced pollen viability as well as germination in ice1-2 were due to abnormal anther dehydration, for most of anthers dehisced with drought treatment and pollen grains from those dehydrated (脱水的) anthers had similar viability and germination rates compared with wild type. Accordingly, the sterility of ice1-2 could be rescued by ambient dehydration treatments. Likewise, the stomatal differentiation of ice1-2 anther epidermis was disrupted in a different manner compared with that in leaves. ICE1 specifically bound to MYC-recognition elements in the promoter of FAMA, a key regulator of guard cell differentiation, to activate FAMA expression. Transcriptome profiling in the anther tissues further exhibited ICE1-modulated genes associated with water transport and ion exchange in the anther. Together, this work reveals the key role of ICE1 in male fertility control and establishes a regulatory network mediated by ICE1 for stomata development and water movement in the anther.

ICE1编码一个bHLH转录因子，在植物响应冷害和冻害及叶片气孔发育过程中发挥重要作用。然而，目前为止还没有有关ICE1在生殖发育中所起作用的报道。本文的研究显示ICE1通过影响花药脱水来控制植物的雄性育性。拟南芥ICE1基因功能缺失突变体存在花药不开裂、花粉活力低及萌发率低等问题。进一步的研究显示ice1-2突变体的花药存在裂缝的结构，但是花药的表皮并不缩水开裂。ice1-2突变体的花药不开裂、花粉活力和萌发率低等缺陷均是由异常的花药脱水所引起的，大部分突变体的不开裂花药在经过干旱处理之后，花粉的活力及萌发率与野生型无异。此外，ice1-2突变体的花药缺陷表型能够被环境脱水所恢复。而且，ice1-2突变体花药表皮上气孔的分化模式受到破坏，与叶片上气孔的分化模式不一样。ICE1能够特异性的结合到保卫细胞分化的关键调控子FAMA基因的启动子区识别元件，以促进FAMA基因的表达。花药的转录组分析显示ICE1调控的基因与水分运输和离子转运相关。综上，本文的研究揭示了ICE1在雄心育性控制方面的作用，并且成功建立了由ICE1介导花药中气孔发育和水分运输的基因调控网络。

通讯：林娟（http://life.fudan.edu.cn/Data/View/1370）

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�个人简介：1984年，陕西师范大学，生物教育学士；1996年，四川大学，植物遗传硕士；2002年，四川大学，生物学博士；2002-2004年，复旦大学，遗传工程国家重点实验室博士后。

研究方向：利用遗传学、分子生物学、生物信息学和组学等手段, 研究植物抵抗逆境的分子机理。主要包括：(1)荠菜抗冷途径关键基因的功能；(2)植物逆境响应的关键基因在调控植物生长和发育的分子机制。

doi: https://doi.org/10.1371/journal.pgen.1007695

Journal: PLOS Genetics

Published date: 04 October, 2018

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