ECOTHERM – Exploring the natural variation of the heat shock response in Arabidopsis thaliana to understand the molecular mechanism of heat perception

ECOTHERM â 探索拟南芥热激反应的自然变化，了解热感知的分子机制

• 批准号: 416992417
• 负责人: Dr. Daniel Maag
• 金额: --
• 依托单位: Lehrstuhl für Pharmazeutische Biologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/416992417?language=en
• 关键词: ECOTHERM; Exploring; natural; variation; heat

Exposure to moderately elevated temperatures elicits a genetically encoded heat shock response (HSR) resulting in short-term acquired thermotolerance, which enables plants to withstand a subsequent temperature extreme that is lethal to non-acclimated plants. The HSR is characterised by a substantial transcriptional and metabolic reprogramming that is tightly regulated by a complex network of transcription factors. Central to this regulatory network is the activation of HEAT SHOCK TRANSCRIPTION FACTORs belonging to the A1 subfamily (HSFA1s). Despite the fact that the HSR has been relatively well characterised at the molecular level in Arabidopsis thaliana it is still unclear how an increase in temperature is sensed by the plant and how this initial signal translates into HSFA1 activation. In addition, knowledge on the natural variation of A. thaliana’s temperature responsiveness and the underlying mechanisms is limited. In our preliminary work we observed a significant variation in the ability to acquire thermotolerance across ten Arabidopsis accessions. In addition, plant survival correlated with the accumulation of raffinose, a trisaccharide whose temperature-dependent synthesis is positively regulated by HSFA1, making it a promising marker trait for the onset of the HSR. Based on these observations we propose to exploit the temperature-dependent raffinose accumulation to (I) gain insights into the genetic architecture of HSFA1-dependent signalling and the mechanisms underlying its intraspecific variation and (II) to identify candidate genes that are involved in temperature perception as well as yet unknown components of the HSFA1 signalling cascade in a genome-wide association study (GWAS). We will follow a two-step approach with an initial characterisation of HSR-related marker traits in 100 A. thaliana accessions that will result in the identification of extreme accessions and also allow for fine-tuning of the experimental conditions for the large-scale phenotyping at the second step. The identified extreme accessions will be characterised in detail at the metabolic and transcriptomic level using lipidomics and RNAseq. Transcription rates of selected differentially expressed genes will then be profiled across the 100 accessions and the data used for the generation of transcriptional networks resulting in the identification of the central regulatory elements underlying the observed intraspecific variation. At the second step, we will screen the temperature responsiveness of 1135 A. thaliana accessions whose genomes have been published recently thereby providing an excellent resource for GWA studies. The most significant candidate genes will be characterised and their exact role in temperature perception and acquired thermotolerance determined.Taken together, the proposed project will provide valuable insights into the molecular mechanism of temperature sensing as well as mechanisms of local adaptation to extreme temperatures.

暴露于适度升高的温度激发了基因编码的热激反应（HSR），导致短期获得的耐热性，这使得植物能够承受随后的极端温度，该极端温度对于未驯化的植物是致命的。HSR的特征在于大量的转录和代谢重编程，其受到复杂的转录因子网络的严格调控。该调节网络的中心是激活属于A1亚家族（HSFA1）的热休克转运因子。尽管事实上HSR已经在拟南芥中的分子水平上得到了相对较好的表征，但仍然不清楚植物如何感知温度的升高以及这种初始信号如何转化为HSFA1激活。此外，还对A.拟南芥的温度响应性和潜在机制是有限的。在我们的初步工作中，我们观察到一个显着的变化的能力，获得耐热性在10个拟南芥加入。此外，植物存活与棉子糖的积累相关，棉子糖是一种三糖，其温度依赖性合成受HSFA1正调控，使其成为HSR发作的有希望的标记性状。基于这些观察结果，我们建议利用温度依赖性棉子糖积累（I）深入了解HSFA1依赖性信号传导的遗传结构及其种内变异的机制，以及（II）在全基因组关联研究（GWAS）中识别参与温度感知的候选基因以及HSFA1信号传导级联的未知组分。我们将遵循一个两步的方法，在100 A中对HSR相关标记性状进行初步表征。这将导致极端种质的鉴定，并允许在第二步中对大规模表型分析的实验条件进行微调。将使用脂质组学和RNAseq在代谢和转录组学水平上详细表征所鉴定的极端种质。然后，将在100份材料中对所选差异表达基因的转录率进行分析，并将数据用于生成转录网络，从而鉴定所观察到的种内变异的核心调控元件。第二步，对1135A的温度响应性进行筛选.拟南芥种质的基因组最近已公布，从而为GWA研究提供了极好的资源。最重要的候选基因将被描述，并确定它们在温度感知和获得耐热性中的确切作用。综合起来，拟议的项目将为温度感知的分子机制以及局部适应极端温度的机制提供有价值的见解。