Adaptation inception: implanting epigenetic memories of cold stress in cereals

极端天气的频率、强度和持续时间的变化是气候变化的后果，对农业环境构成挑战。可悲的是，对植物适应环境变化的机制的有限理解限制了我们为这些后果做准备的能力。温带植物通过调整其物候适应低温而持续存在，是适应性研究的有用系统。未驯化的二穗短柄草是研究冷适应的一个强大的谷物模型，因为它自然生长在经常发生冰冻的环境中，显示出一系列春化要求，并且正如我们实验室首次证明的那样，可以在冷驯化后增加其抗冻能力。我们的长期目标是了解和操纵基于染色质的调控机制参与谷物对环境胁迫的反应，以减轻其对生产发展的影响。最近的工作牵连染色质为基础的机制，不仅在转录调控，而且在记录特定的记忆，可以触发更强，更快的细胞反应，在以前的挑战植物的压力。因此，我们假设，表观基因组的动态调整是一个关键的调节机制，引发植物对不断变化的环境的反应，并支持适应。目的1和2将表征冷适应B的染色质状态。通过分别鉴定组蛋白修饰和DNA甲基化的变化来检测二穗草。这些目标将允许与低温波动相关的染色质标记的全基因组欣赏。目标2也将查询B的输入。冷反应中二穗子的从头DNA甲基化途径。这一目标将连接从头甲基化途径，这是牵连在表观遗传记忆形成的压力诱导的基因座，植物的能力，记录和应对低温事件。目标3，我们希望通过植入冷暴露的人工记忆来增强谷物的耐寒性。在这里，我们建议通过在B中部署基于CRISPR的工具来设计目标1和2中观察到的启动染色质记忆状态。二穗子这种新的方法将允许植物在不首先暴露于生长限制触发器的情况下应对压力。重要的是，aim 3将测试表观基因组编辑在作物中增强抗逆性的可行性。总之，提出的工作将提供新的见解植物染色质动态响应环境线索。使用CRISPR工具重塑染色质将刺激谷类作物的改良，并进一步为关于使用非传统育种方法的辩论提供信息。因此，我们的工作将转化为健全的作物生产系统、可持续的粮食安全和较低的价格。最后，它将提供能够创建，评估和监管来自表观遗传和编辑技术的农产品的HQP。

Changes in the frequency, intensity and duration of weather extremes are consequences of climate change and impose challenges to agroenvironments. Sadly, the limited understanding of plants' adaptive mechanisms to changing environments restrains our ability to prepare for these consequences. Temperate plants persist by adjusting their phenology to low temperatures and are useful systems for adaptation studies. The undomesticated Brachypodium distachyon is a powerful cereal model to study cold adaptation because it naturally grows in environments where freezing spells are frequent, displays a range of vernalization requirements and as our lab first demonstrated, can increase its freezing tolerance capacity upon cold acclimation. Our long-term goal is to understand and manipulate chromatin-based regulatory mechanisms involved in cereal responses to environmental stresses to mitigate their impact on productive development. Recent work implicates chromatin-based mechanisms not only in transcriptional regulation but also in recording specific memories of stresses that can trigger stronger, more rapid cellular responses in previously challenged plants. We thus hypothesize that dynamic tuning of epigenomes is a key regulatory mechanism that primes plant responses to changing environments and supports adaptation. Aims 1 and 2 will characterize chromatin states of cold-acclimated B. distachyon by respectively identifying changes in histone modifications and DNA methylation. These aims will allow a genome-wide appreciation of chromatin marks associated with low temperature fluctuations. Aim 2 will also query the input of B. distachyon's de novo DNA methylation pathway in cold responses. This aim will link the de novo methylation pathway, which is implicated in epigenetic memory formation at stress-induced loci, to the plant's capacity to record and respond to low temperature events. With aim 3, we hope to engineer cereals with enhanced cold tolerance by implanting artificial memories of cold exposure. Here, we propose to engineer the primed chromatin memory states observed in aims 1 and 2 by deploying CRISPR-based tools in B. distachyon. This novel approach will allow plants to be primed for stress without first being exposed to growth-limiting triggers. Importantly, aim 3 will test the feasibility of epigenome editing in crops to enhance stress resilience. Together, the work proposed will provide novel insights on plant chromatin dynamics in response to environmental cues. The use of CRISPR tools to reshape chromatin will galvanize cereal crop improvement and further inform the debate on the use of non-traditional breeding approaches. Our work will thus translate to robust crop production systems, sustainable food security and lower prices. Finally, it will provide HQP capable of creating, assessing and regulating agricultural products derived from epigenetic and editing technologies.