拟南芥PPR蛋白TSL1协调温度信号与叶绿体发育的分子机理

Abiotic stresses such as high temperature directly affect plant growth and development, which is a great threat to the stable and high grain yield production, and the threat will increase with the global climate change. High temperature often inhibits chloroplast development, resulting in decreased photosynthetic efficiency. In order to cope with high temperature stress, plants have obtained a series of mechanisms to maintain the normal development of chloroplast during evolution, but few related molecular mechanisms were discovered. In the previous study, we obtained a recessive loss-of-function mutant of tsl1 (thermosensitive leaf color mutant 1) through EMS screening. The tsl1 mutant had no obvious phenotype under the normal growth temperature (22 °C-25 °C). The true leaves of tsl1 mutant turned yellow at 26 °C, and further ivory at 29 °C while the true leaves of wild-type remained green under the same temperature growth conditions. Further studies showed that the chloroplast development of tsl1 mutant was significantly impaired, and the chloroplast mRNA editing process in tsl1 mutant was widely affected in general under high temperature conditions. At present, the gene has been cloned, encoding a non-classical PPR protein, whose function has not been reported. The project will take the tsl1 mutant as an opportunity to focus on how TSL1 senses environmental temperature changes and regulates chloroplast mRNA editing. Through the analysis of the function of TSL1, new molecular mechanisms for coordinating environmental temperature signals and chloroplast development can be explored to enhance our understanding of the molecular mechanism of plant adaptation to environmental temperature change.

高温等非生物逆境胁迫直接影响植物的生长发育，是粮食稳产、高产的巨大威胁。高温常常抑制叶绿体发育，导致光合效率下降。植物在进化过程中形成了一系列维持高温胁迫下叶绿体正常发育的机制，但其相关分子机理研究较少。前期的研究中我们筛选得到一个tsl1隐性功能缺失突变体，该tsl1突变体正常生长温度（22℃-25℃）条件下没有明显表型，生长环境温度升高到26℃时突变体真叶变黄，到29℃时真叶完全变白，而野生型在同样温度下真叶仍保持绿色。进一步研究发现只有在高温下tsl1突变体的叶绿体发育明显受到影响，叶绿体mRNA的编辑受到广泛影响。目前该基因已被克隆，编码一个非经典的PPR蛋白，其功能未见报道。本项目重点研究TSL1如何感应环境温度变化和调控植物叶绿体mRNA编辑的分子机理。通过对TSL1的功能的分析，可以探明植物协调环境温度信号和叶绿体发育的新机制，增强我们对植物适应环境温度升高的分子机理的理解。

不利的生长条件，如干旱、盐碱、极端温度等是影响植物生长的重要因素，是粮食稳产、高产的巨大威胁。叶绿体是绿色植物进行光合作用的重要细胞器。叶绿体的形成和发育是一个严密精细调控的过程，受光、温度等环境因素影响很大。高温常常抑制叶绿体发育，导致光合效率下降。为了应对高温胁迫，植物在进化过程中形成了一系列维持叶绿体正常发育的机制，但其相关分子机理研究较少。本项目重点研究了植物协调环境温度与叶绿体发育的分子机制，揭示PPR家族蛋白TSL1/DG1的功能和作用机制，发现了TSL1在环境高温响应中的重要功能，阐明了TSL1调控植物叶绿体mRNA编辑的分子机制。揭示了TSL2/FtsHi5在环境低温响应中的重要功能，阐明了TSL2调控叶绿体蛋白定位与积累中的分子机理，相关成果发表在J Genet Genom、Front Plant Sci等杂志上。撰写了叶绿体发育与温度响应的关系的综述，发表在Plant Cell Physiol上。这些研究增强我们对植物适应环境温度变化的分子机理的理解。本项目也研究了拟南芥在温和高温下下胚轴伸长的调控机制，植物对高温胁迫的响应分子机制，相关成果在J.Integr Plant Biol、Plant J等杂志上发表。