The novel gene 'Histone Deacetylase Complex 1' enhances plant growth and abiotic stress tolerance; where, when and with whom?

新基因“组蛋白脱乙酰酶复合物 1”增强植物生长和非生物胁迫耐受性；

基本信息

批准号：
BB/K008218/1
负责人：
Anna Amtmann
金额：
$ 42.74万
依托单位：
University of Glasgow
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FK008218%2F1
关键词：
novel gene Histone Deacetylase Complex

项目摘要

Climate change and a growing world population are expected to lead to water scarcity and food shortage in the near future. There is an urgent need to increase yield, water usage efficiency and stress tolerance of food crops. We propose to achieve this through controlled manipulation of plant sensitivity to the 'stress' hormone abscisic acid (ABA). The project builds on our recent discovery of a novel gene from Arabidopsis thaliana, which we called 'Histone de-acetylation complex 1' (HDC1). We found that over-expression of HDC1 led to decreased ABA-sensitivity of germinating seeds and to enhanced growth of mature plants, while deletion of HDC1 had the opposite effects. Thus HDC1 can be used as an adjustable 'hormostat'. This property makes HDC1 an attractive target for crop improvement. For example, in a drought-prone rain-fed field increasing ABA-sensitivity will aid plant recovery after dehydration whereas in an irrigated field decreasing ABA-sensitivity could be a means to sustain biomass production with reduced water input. The question is then; how does HDC1 change ABA-sensitivity? Ancestral precursors of HDC1 in yeast are members of large multi-protein complexes that biochemically modify (de-acetylate) histone proteins that are associated with DNA (chromatin). Histone de-acetylation (HD) determines the overall structure of the DNA which in turn exerts a hyper-level of control over gene activity. Our current hypothesis is that HDC1 'titrates' the stability of a chromatin complex thereby modifying accessibility of the DNA to ABA-dependent regulators and hence ABA-sensitivity. This is an exciting concept because it means that via HDC1 one could gain control over a whole suite of stress responses without the need to tinker with the underlying complex signalling network. However, to exploit the opportunities presented by HDC1 for crop improvement we need to understand exactly how HDC1 operates at the molecular level. For example, the composition of HD complexes and the precise functions of proteins therein are completely unknown in plants. The aim of this project is to investigate the molecular function of HDC1 in the model plant Arabidopsis. This research will run in parallel to a crop development programme carried out by the Industrial Partner. Reciprocal information flow between the two research programmes will ensure that fundamental discoveries made in the model species can immediately be translated into crop improvement. The work programme has three parts. In the first work package we will use an antibody against HDC1 to identify 'by association' other members of the HDC1-complex in plant protein extracts. We will obtain mutant lines for some of the identified associates and cross them with the HDC1mutant lines. This work will lead to a first understanding of HD complexes in plants, and to the identification of proteins that limit or enhance HDC1 function within the complex. The second work package addresses the question whether HDC1 itself is regulated and how. In particular, we will investigate whether HDC1 is a target for 'hijacking' of the ABA pathways by other hormones ('cross talk') or by pathogens. For this purpose we will measure HDC1 protein levels in plant extracts treated with hormones and pathogen elicitors. In the third work package we will investigate which genes cause the effects of HDC1 on seed germination and growth - the 'targets' of HDC1. In the first instance we will identify all genes that are differentially expressed in wildtype and HDC1 mutant plants using gene chips. To identify the DNA regions that are directly targeted by HDc1 we will pull-down HDC1-associated chromatin with the HDC1-antibody. Finally, we will measure acetylation levels of the chromatin with antibodies that recognize acetylated histone tails. The combined outcomes from this work will greatly enhance our understanding of gene regulation in plants and directly contribute to improving yield and water usage efficiency in crops.

气候变化和世界人口的增长预计将在不久的将来导致水资源短缺和粮食短缺。迫切需要提高粮食作物的产量、用水效率和抗逆性。我们建议通过控制植物对“应激”激素脱落酸（ABA）的敏感性来实现这一目标。该项目建立在我们最近从拟南芥中发现的一种新基因的基础上，我们将其称为“组蛋白去乙酰化复合物 1”(HDC1)。我们发现HDC1的过度表达导致发芽种子的ABA敏感性降低并促进成熟植物的生长，而HDC1的缺失则具有相反的效果。因此，HDC1 可以用作可调节的“激素调节器”。这一特性使 HDC1 成为作物改良的一个有吸引力的目标。例如，在易发生干旱的雨养田中，提高 ABA 敏感性将有助于脱水后植物的恢复，而在灌溉田中，降低 ABA 敏感性可能是通过减少水输入维持生物量生产的一种手段。那么问题是； HDC1 如何改变 ABA 敏感性？酵母中 HDC1 的祖先前体是大型多蛋白复合物的成员，该复合物对与 DNA（染色质）相关的组蛋白进行生化修饰（去乙酰化）。组蛋白去乙酰化 (HD) 决定 DNA 的整体结构，进而对基因活性发挥超水平的控制。我们目前的假设是，HDC1“滴定”染色质复合物的稳定性，从而改变 DNA 对 ABA 依赖性调节因子的可及性，从而改变 ABA 敏感性。这是一个令人兴奋的概念，因为它意味着通过 HDC1，人们可以控制一整套应激反应，而无需修补底层的复杂信号网络。然而，为了利用 HDC1 带来的机会来改良作物，我们需要准确了解 HDC1 在分子水平上的运作方式。例如，HD复合物的组成和其中蛋白质的精确功能在植物中是完全未知的。该项目的目的是研究 HDC1 在模式植物拟南芥中的分子功能。这项研究将与工业合作伙伴开展的作物开发计划同时进行。两个研究项目之间的相互信息流将确保在模型物种中取得的基本发现可以立即转化为作物改良。工作计划分为三个部分。在第一个工作包中，我们将使用针对 HDC1 的抗体来“通过关联”识别植物蛋白提取物中 HDC1 复合物的其他成员。我们将获得一些已识别的相关联的突变系，并将它们与 HDC1 突变系杂交。这项工作将导致人们首次了解植物中的 HD 复合物，并鉴定出限制或增强复合物内 HDC1 功能的蛋白质。第二个工作包解决了 HDC1 本身是否受到监管以及如何监管的问题。特别是，我们将研究 HDC1 是否是其他激素（“串扰”）或病原体“劫持”ABA 途径的目标。为此，我们将测量经激素和病原体诱导剂处理的植物提取物中的 HDC1 蛋白水平。在第三个工作包中，我们将研究哪些基因导致 HDC1 对种子发芽和生长的影响 - HDC1 的“目标”。首先，我们将使用基因芯片识别野生型和 HDC1 突变体植物中差异表达的所有基因。为了识别 HDc1 直接靶向的 DNA 区域，我们将使用 HDC1 抗体下拉 HDC1 相关染色质。最后，我们将使用识别乙酰化组蛋白尾部的抗体来测量染色质的乙酰化水平。这项工作的综合成果将极大地增强我们对植物基因调控的理解，并直接有助于提高作物的产量和水分利用效率。