H₂O₂在调控大豆环式电子传递和耐盐机制中的作用

NDH (NAD(P)H dehydrogenase complex)-dependent Cyclic Electron Flow (CEF) plays an important role when plant was exposed to stress environments. Meanwhile, stress environments induced the production of Reaction Oxygen Species (ROS). However, under stress conditions, the relationship between ROS and CEF is not yet clear. This research is based on the previous works, according to studying the H₂O₂ content and the change of CEF in leaf, and effect of H₂O₂ on the CEF of soybean, the formation of chloroplast protrusion and the expression of NDH complex-related genes under salt stress. The aim is to elucidate how CEF is initiated under stress conditions and whether H₂O₂ play a critical role in initiating CEF? Whether induced NDH-dependent CEF was used to resisting the rapid degradation of chloroplast that was favor of promoting the salt-tolerant ability of photosynthetic apparatus? This project is not only helpful to our understanding for the defense signal transduction under stress conditions, but also has an important theoretical significance and application value for the improvement of crop salt tolerance.

NAD(P)H脱氢酶（NDH）复合体介导的环式电子流（CEF）在植物遭受环境胁迫时发挥重要作用，同时逆境也诱导活性氧（ROS）的产生。然而, 逆境条件下ROS与CEF之间存在什么关系还不清楚。本研究在前期工作的基础上，通过盐胁迫下叶片中H₂O₂含量与CEF变化，H₂O₂对大豆CEF和叶绿体突起形成和NDH复合体相关基因表达等研究，目的在于揭示逆境条件下CEF是如何发生的，H₂O₂是否在诱导该CEF中发挥核心作用？是否通过诱导NDH介导的CEF抵御叶绿体的快速分解，从而提高光合器官的耐盐性？这对认清盐胁迫下的防御信号转导，提高作物抗盐性有重要的理论意义和一定的应用价值。

增加大豆的抗盐性是提高盐胁迫条件下大豆产量的重要途径，前期的研究表明提高NDH介导的围绕光系统I的环式电子流（CEF）能提高大豆盐胁迫下的光合作用，减轻盐害损伤。而逆境条件下活性氧信号可能是提高抗性的原因之一。为了明确H2O2是否能诱导CEF，以及该信号是否具有可传递性和它与盐胁迫的关系，我们利用不同耐盐性大豆品系，通过运用组织荧光染色结合振动切片、ATP含量测定和qRT-PCR等技术方法，阐明了H2O2可以作为信号分子通过质外体途径在叶与叶之间传递，且传递快慢与大豆品系的耐盐性有关。同时，明确了盐胁迫能引起大豆叶片中H2O2含量的增加，增加的H2O2含量能有效地诱导大豆叶片中NDH复合体介导的CEF活性的增强。在盐胁迫下，由H2O2诱导的NDH复合体介导的CEF活性与其叶绿体降解的速度呈负相关。通过此研究的开展，进一步明确了H2O2能通过NDH复合体介导的CEF途径在大豆耐盐性中发挥作用。