集胞藻PCC6803中S2P蛋白酶Slr1821参与热胁迫响应的研究

Exploration of the Involvement of the S2P Protease Slr1821 of Synechocystis sp. PCC6803 in Heat Stress Response

摘要:

随着全球CO2排放量不断上升，温室效应日益加剧，全球气候变暖对农作物生长甚至生态环境的破坏日渐严重，研究光合自养生物对热胁迫的响应机制有科学意义和应用前景。集胞藻PCC6803是一种研究光合作用和非生物胁迫响应等生物过程的模式蓝细菌，本文通过同源双交换完全敲除集胞藻PCC6803的S2P蛋白Slr1821的编码基因，构建了缺失突变体Δslr1821，发现经过高温44 ℃热处理后，突变体完全不能生长，而野生型能够快速恢复热损伤，揭示Slr1821蛋白在热胁迫适应中发挥重要的作用。通过研究藻胆蛋白相对含量和叶绿素含量的变化，发现该基因缺失抑制了细胞热处理后的光合色素包括藻胆蛋白和叶绿素的重新合成，为研究光合自养生物适应热胁迫调控机制提供了新的视角和思路。

Abstract:

With the rising emission of carbon dioxide(CO2), the greenhouse effect is becoming increasingly obvious, and global warming has caused more severe damage to the growth of crops and the ecological environment. Thus, investigation of the response mechanism of photosynthetic autotrophs to heat stress is of scientific significance and has potential applications. Synechocystis sp. PCC6803 is a model cyanobacterium used to study photosynthesis and the response to abiotic stress. In this paper, the coding gene of the site-2-protease Slr1821 of Synechocystis sp. PCC6803 was knocked out completely by homologous recombination to generate the Δslr1821 mutant. The results showed that after heat treatment at 44 ℃, the Δslr1821 mutant could not grow at all, whereas the wild-type recovered from thermal damage quickly, indicating that Slr1821 protein played an important role in heat acclimation. Through analysis of changes in the relative content of phycobiliprotein and the content of chlorophyll, the results showed that heat treatment-induced deficiency of slr1821 inhibited the resynthesis of photosynthetic pigments, including phycobiliprotein and chlorophyll. These findings provide important insights into analysis of the mechanisms through which photosynthetic autotrophs adapt to heat stress.