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PNAS:ABA通过磷酸化NST1调控次生细胞壁形成和木质素沉积

已有 715 次阅读 2021-2-1 14:18 |个人分类:每日摘要|系统分类:论文交流

Abscisic acid regulates secondary cell-wall formation and lignin deposition in Arabidopsis thaliana through phosphorylation of NST1

第一作者Chang Liu

第一单位北德克萨斯大学

通讯作者Richard A. Dixon


 Abstract 


背景回顾Plant secondary cell-wall (SCWdeposition and lignification are affected by both seasonal factors and abiotic stress, and these responses may involve the hormone abscisic acid (ABA).


提出问题:However, the mechanisms involved are not clear.


主要发现:Here we show that mutations that limit ABA synthesis or signaling reduce the extent of SCW thickness and lignification in Arabidopsis thaliana through the core ABA-signaling pathway involving SnRK2 kinases.


结果1-物理互作SnRK2.2. 3 and 6 physically interact with the SCW regulator NAC SECONDARY WALL THICKENING PROMOTING FACTOR 1 (NST1), a NAC family transcription factor that orchestrates the transcriptional activation of a suite of downstream SCW biosynthesis genes, some of which are involved in the biosynthesis of cellulose and lignin.


结果2-磷酸化:This interaction leads to phosphorylation of NST1 at Ser316, a residue that is highly conserved among NST1 proteins from dicots, but not monocots, and is required for transcriptional activation of downstream SCW-related gene promoters.


结果3-功能突变Loss of function of NST1 in the snd1 mutant background results in lack of SCWs in the interfascicular fiber region of the stem, and the Ser316Ala mutant of NST1 fails to complement this phenotype and ABA-induced lignin pathway gene expression.


结论:The discovery of NST1 as a key substrate for phosphorylation by SnRK2 suggests that the ABA-mediated core-signaling cascade provided land plants with a hormone-modulated, competitive desiccation-tolerance strategy allowing them to differentiate water-conducting and supporting tissues built of cells with thicker cell walls.

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 摘 要 


植物次生细胞壁沉积和木质化受到季节因素和非生物胁迫的影响,这些响应可能涉及植物激素脱落酸(ABA)。但是,具体的机制还不清楚。本文中,作者发现拟南芥ABA合成或信号转导功能受限的突变体中,次生细胞壁厚度和木质化程度降低,而这是由涉及SnRK2激酶的核心ABA信号转导途径所介导的。SnRK2.2、SnRK2.3和SnRK2.6能够与次生细胞壁调控因子NAC家族转录因子的一员NST1物理互作,NST1能够转录激活下游的次生细胞壁合成基因,其中一些基因参与了纤维素和木质素的生物合成。SnRK2和NST1的物理互作直接导致NST1在第316位上的丝氨酸被磷酸化,这个位置上的丝氨酸在所有双子叶植物的NST1中高度保守,但是在单子叶植物中并不保守,作用于下游次生细胞壁相关基因启动子的转录激活。snd1突变体背景植株中再缺失NST1功能,会导致茎中束间纤维区的次生细胞壁缺失,并且将NST1第316位上的丝氨酸突变为丙氨酸,不能互补之前的表型缺陷和ABA诱导的木质素通路基因的表达。NST1作为SnRK2磷酸化的关键底物的发现表明,ABA介导的核心信号级联为陆地植物提供了一种激素调节的竞争性耐脱水策略,使得其能够分化出由细胞壁较厚的细胞所构成的导水和支撑组织。


 通讯作者 

**Richard A. Dixon**


个人简介:

英国牛津大学,学士;

英国牛津大学,博士;

英国剑桥大学,博后。


研究方向:植物天然产物通路的生物化学、分子生物学和代谢工程及其对农业和人类健康的影响,以及改善饲料和生物能源原料的木质纤维素生物质工程。


doi: https://doi.org/10.1073/pnas.2010911118


Journal: PNAS

Published date: Feb 02, 2021



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