Understanding the role of chromatin modifying complexes in the abiotic stress response mechanisms of cereal plants

植物经常暴露于它们必须适应的环境胁迫（例如低温）。这些压力调节参与压力反应机制的重叠基因组的表达。我们的长期目标是了解控制重要农艺性状的染色质机制，如谷物的非生物胁迫耐受性。我们假设，除了转录元件的作用，染色质的动态调谐后感知的压力是一个重要的调节机制，必要的适应。 为了实现这一目标，我们将建立在我们的第一个NSERC发现赠款产生的知识和势头。在2015-2020年资助期间，我们将专注于3个新目标：1）确定春季，兼性和冬季短柄草种质的冷驯化参数，以获得最佳的抗冻性发展。我们已经确定，常用的7加入有兼性或冬季的习惯。然而，现在有180多个二倍体种质，为我们提供了发现具有真正春季（敏感）和冬季（耐受）习性的种质的机会。这将使我们能够进行功能比较分析; 2）表征BdADA 2在低温染色质动力学中的作用。已知SAGA靶向基因受应激调控，我们已经在植物中表明，这种复合物的重要组成部分-ADA 2-与CBF 1相互作用。我们已经产生了过表达ADA 2的短柄草属转基因品系。这些细胞系在GCN 5靶向的H3赖氨酸处具有增加的乙酰化，以及一些COR基因的表达降低。这些细胞系将用于提供证据，证明CBF 1和ADA 2之间的相互作用可能代表冷硬化的转录和染色质调控反应之间的整合节点; 3）表征DNA甲基化在短柄草属冷硬化过程中的作用。DNA甲基化被认为在谷物的冷驯化反应中起主导作用。我们已经产生了短柄草敲低和过表达的几个关键基因的这一途径：DRM 2，CMT 3和AGO 4。我们将这些品系暴露于低温，以揭示DNA甲基化在冷驯化过程中的重要性，这将精确这些修饰剂在单子叶植物中的作用。这个独特的项目，旨在了解染色质控制的胁迫耐受性在谷物将有一个重大的影响，表观遗传学研究的其他分类群体的普遍逻辑所涉及的分子电路。此外，我们的研究将通过利用特定的染色质修饰剂进行遗传和表观遗传编辑策略，从而制定改善作物重要性状的策略。随着对表观遗传学HQP需求的增加，该项目将培养3名博士，2名硕士和几名本科生。

Plants are constantly exposed to environmental stresses (e.g. low temperature) to which they must adapt. These stresses regulate the expression of overlapping suites of genes involved in stress response mechanisms. Our long-term goal is to understand the chromatin mechanisms that control agronomically important traits such as abiotic stress tolerance in cereals. We hypothesize that in addition to the role of transcriptional elements, the dynamic tuning of chromatin upon perception of stress is a major regulatory mechanism necessary for adaptation.  To achieve this goal, we will build on knowledge and momentum generated by our first NSERC Discovery grant. During the 2015-2020 funding period we will focus on 3 new objectives: 1) Determine the cold acclimation parameters of spring, facultative and winter Brachypodium accessions for optimal freezing tolerance development. We have established that the 7 accessions commonly used have either facultative or winter habits. However, more than 180 diploid accessions are now available, offering us the opportunity to uncover accessions with true spring (sensitive) and winter (tolerant) habits. This will allow us to perform functional comparative analyses; 2) Characterize the role of BdADA2 in low temperature chromatin dynamics. SAGA-targeted genes are known to be regulated by stress and we have shown in planta that an important component of this complex - ADA2 - interacts with CBF1. We have generated Brachypodium transgenic lines that overexpress ADA2. These lines have increased acetylation at the H3 lysines targeted by GCN5, as well as reduced expression of some COR genes. These lines will be used to provide evidence that the interaction between CBF1 and ADA2 potentially represents an integration node between the transcriptional and chromatin regulatory responses of cold hardening; 3) Characterize the role of DNA methylation during cold hardening in Brachypodium. DNA methylation is believe to play a predominant role in the cold acclimation response of cereals. We have generated Brachypodium knockdown and overexpression lines for several key genes of this pathway: DRM2, CMT3 and AGO4. We will expose these lines to low temperatures to reveal the importance of DNA methylation during cold acclimation, which will precise the role of these modifiers in monocots. This unique project aiming at understanding chromatin control of stress tolerance in cereals will have a major impact on epigenetic research on other taxonomic groups given the universal logic to the molecular circuitry involved. In addition, our research will lead to the development of strategies for the improvement of important traits in crops by harnessing specific chromatin modifiers for genetic and epigenetic editing strategies. In line with the increasing need for HQP in epigenetics, this project will train 3 PhD, 2 MSc and several undergraduate students.