Physiological drought stress imprints related to root exudation in the rhizosphere

与根际根系分泌物相关的生理干旱胁迫印记

• 批准号: 403626025
• 负责人: Dr. Monika Wimmer
• 金额: --
• 依托单位: Department Molekulare Systembiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/403626025?language=en
• 关键词: Physiological; drought; stress; imprints; related

In Central Europe, transient drought spells are predicted to increase due to climate change. So-called “stress imprints” describe modifications in plants that occur after a stress event and improved responses to subsequent stresses. Such modifications are in the focus of this project. Root exudates are altered under drought stress to facilitate root growth into the drying soil, but it remains an open question (i) whether physiological drought stress imprints related to root exudation occur in the rhizophere, (ii) in which spatio-temporal pattern root exudation responds to stress severity, duration and stress onset type, and (iii) how metabolic re-organization of the root system in response to drought affects post-stress plant performance with respect to stress resilience and nutrient uptake.This project addresses four hypotheses: (1) physiological drought stress imprints occur in the rhizosphere and are mediated by altered root exudation; (2) the extent of these imprints depends on the speed of onset, severity and duration of the drought event and concomittant damage to the photosystem; (3) these imprints lead to spatio-temporal re-distribution of resources towards the root and (4) they affect post-stress plant performance with respect to water and nutrient uptake. In this project, plants are exposed to different drought stress types including different intensities, durations and speeds of progression. Exudate production is determined by collecting exudates and composition is assessed by LC-MS analyses. Photosynthesis-related processes are monitored during the progression of drought, and damage to the photosystem is assessed by chlorophyll fluorescence and biochemical stress markers. The persistence of the stress imprints is determined by time course analysis during re-watering. In a rhizobox setup, one half of the roots is exposed to a single, and one half to recurrent drought drought spells. Root exudates are collected from both root halves and metabolic reorganisation of the whole plant as well as metabolic crosstalk between the root halves is monitored using a proteomic approach. Post stress plant performance is analysed by assessing the recovery time for water relations in the plant and uptake of nutrients, complemented by expression studies of aquaporins and selected nutrient transporters. The pot experiments are complemented by similar analyses of exudates collected from root windows in the field.The outcomes of these studies will provide information on the spatio-temporal interplay between drought-induced changes in photosynthetic processes aboveground, and their lasting imprints on rhizosphere-based processes belowground, mediated by alterations in root exudates. They help to gain a mechanistic understanding of underlying metabolic responses of the system root/shoot which may lead to an improved post-stress performance under conditions of sub-optimum growth conditions after drought.

在中欧，由于气候变化，预计短暂的干旱会增加。所谓的“压力印记”描述了在压力事件之后发生的植物中的修改以及对随后压力的改善的响应。这些修改是本项目的重点。干旱胁迫下，根系分泌物发生变化，促进根系向干燥土壤中生长，但根际是否存在与根系分泌物相关的生理干旱胁迫印记，根系分泌物的时空格局对胁迫强度、持续时间和胁迫类型的响应，以及（iii）根系对干旱的代谢重组如何影响胁迫后植物在胁迫恢复力和养分吸收方面的表现。本项目涉及四个假设：（1）生理干旱胁迫印记发生在根际，并由根系分泌物的改变介导，（2）这些印记的程度取决于干旱事件的发生速度、严重程度和持续时间以及伴随的光系统损害;（3）这些印记导致资源向根部的时空重新分配，以及（4）它们影响胁迫后植物在水和养分吸收方面的表现。在该项目中，植物暴露于不同的干旱胁迫类型，包括不同的强度，持续时间和进展速度。通过收集渗出物测定渗出物产量，并通过LC-MS分析评估组成。在干旱过程中监测与光合作用有关的过程，并通过叶绿素荧光和生化胁迫标记评估对光系统的损害。应力印记的持久性是通过再浇水过程中的时间过程分析来确定的。在根箱设置中，一半的根暴露于单一干旱，一半暴露于周期性干旱。根分泌物收集从两个根的一半和整个植物的代谢重组，以及根的一半之间的代谢串扰使用蛋白质组学方法进行监测。胁迫后的植物性能进行了分析，通过评估恢复时间的水的关系，在植物和营养物质的吸收，水通道蛋白和选定的营养转运蛋白的表达研究的补充。盆栽实验的补充，从根窗在field. Outcomes收集的分泌物类似的分析将提供信息干旱引起的光合作用过程的变化在地上的时空之间的相互作用，其持久的印记根际为基础的过程belowground，介导的根分泌物的变化。它们有助于获得对系统根/茎的潜在代谢反应的机械理解，这可能导致在干旱后次最佳生长条件下的胁迫后性能的改善。