The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 7610000, Israel.
Center for Scientific Imaging Core Facility, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot 7610001, Israel.
Plant Physiol. 2021 Oct 5;187(2):618-631. doi: 10.1093/plphys/kiab159.
Environmental stresses are among the major factors that limit crop productivity and plant growth. Various nondestructive approaches for monitoring plant stress states have been developed. However, early sensing of the initial biochemical events during stress responses remains a significant challenge. In this work, we established whole-plant redox imaging using potato (Solanum tuberosum) plants expressing a chloroplast-targeted redox-sensitive green fluorescence protein 2 (roGFP2), which reports the glutathione redox potential (EGSH). Ratiometric imaging analysis demonstrated the probe response to redox perturbations induced by H2O2, DTT, or a GSH biosynthesis inhibitor. We mapped alterations in the chloroplast EGSH under several stress conditions including, high-light (HL), cold, and drought. An extremely high increase in chloroplast EGSH was observed under the combination of HL and low temperatures, conditions that specifically induce PSI photoinhibition. Intriguingly, we noted a higher reduced state in newly developed compared with mature leaves under steady-state and stress conditions, suggesting a graded stress sensitivity as part of the plant strategies for coping with stress. The presented observations suggest that whole-plant redox imaging can serve as a powerful tool for the basic understanding of plant stress responses and applied agricultural research, such as toward improving phenotyping capabilities in breeding programs and early detection of stress responses in the field.
环境胁迫是限制作物生产力和植物生长的主要因素之一。已经开发出各种用于监测植物胁迫状态的非破坏性方法。然而，早期感知胁迫反应过程中的初始生化事件仍然是一个重大挑战。在这项工作中，我们使用表达叶绿体靶向氧化还原敏感绿色荧光蛋白 2（roGFP2）的马铃薯（Solanum tuberosum）植物建立了全植物氧化还原成像，该蛋白报告谷胱甘肽氧化还原电位（EGSH）。比率成像分析表明，探针对由 H2O2、DTT 或 GSH 生物合成抑制剂引起的氧化还原扰动有响应。我们在包括高光（HL）、寒冷和干旱在内的几种胁迫条件下绘制了叶绿体 EGSH 的变化。在 HL 和低温的组合下，观察到叶绿体 EGSH 极显著增加，这种条件特别诱导 PSI 光抑制。有趣的是，我们注意到在稳定状态和胁迫条件下，与成熟叶片相比，新发育的叶片具有更高的还原态，这表明作为植物应对胁迫策略的一部分，存在逐渐增加的胁迫敏感性。所提出的观察结果表明，全植物氧化还原成像可以作为理解植物胁迫反应和应用农业研究的有力工具，例如提高在育种计划中的表型分析能力和在田间早期检测胁迫反应。
