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Response to high temperature stress and enhancement of high temperature tolerance in plants studies with psychrophilic bacteria and algae

嗜冷细菌和藻类植物研究中对高温胁迫的响应和增强高温耐受性

基本信息

批准号：
08554034
负责人：
HAYASHI Hidenori
金额：
$ 4.61万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

Plants in the natural habitat suffer from the temperature stress, daily, monthly, and yearly fluctuation of temperature. High temperature causes denaturation of proteins in the cells, causing inactivation of important physiological processes and fatal damage. To tolerate these temperature stresses, plants develop a variety of acclimating systems, such as enhancement of heat tolerance of photosynthesis. Production of heat shock proteins. Etc. To understand the responsible mechanisms to high temperature and produce heat tolerant plant by gene manipulation, we carried out the following experiments : 1) screening of proteins which denature at rather low temperature and would helpful to induce heat shock proteins under normal temperature, 2) cloning of heat shock proteins from psychrophilic bacteria which would be expressed under normal or lower temperature 3) introduction of a gene for the chloroplasts-localized small heat shock protein to cyanobacteria to enhance their high temperature tolerance.Some enzymes in psychrophilic bacteria are inactivated at 40-50℃ like those of organisms living under normal temperature, but a ribosomal protein from Prymnesiophyte showed low homology to those of other plants and expected to be cold labile, being useful for induction of heat shock proteins when introduced into normal plants.Cloning of heat shock proteins from psychrophilic bacteria demonstrated amino acid sequence is homologous to those from normal bacteria and it contains nucleotide sequence similar to that in promoter sequence. Indicating psychrophilic bacteria has similar function against high temperature stress, although it is much lower than that for normal bacteria.The expression of Hsp21 resulted in acquisition of thermotolerance in cyanobacteria, especially against lethal high temperature. The results indicates the possibility of enhancement of high temperature tolerance with the gene engineering of heat shock proteins.

自然生境中的植物承受着温度胁迫，每天、每月、每年都有温度波动。高温导致细胞内蛋白质变性，导致重要生理过程失活和致命损伤。为了适应这些温度胁迫，植物发展了各种适应系统，如增强光合作用的耐热性。热休克蛋白的产生。等。为了解植物对高温的作用机制，通过基因操纵培育耐热植物，我们进行了以下实验：(1)筛选在低温下变性并有助于在常温下诱导热休克蛋白的蛋白；(2)从嗜冷细菌中克隆在常温或低温下均可表达的热休克蛋白；(3)在蓝藻中引入叶绿体定位的小热休克蛋白基因，提高其耐高温能力。嗜冷细菌中的一些酶在40-50℃时就会像生活在常温下的生物一样失活，但一种来自原核菌的核糖体蛋白与其他植物的核糖体蛋白同源性较低，预计是冷不稳定的，当引入正常植物时可用于诱导热休克蛋白。从嗜冷细菌中克隆热休克蛋白，发现其氨基酸序列与正常细菌同源，核苷酸序列与启动子序列相似。说明嗜冷细菌对高温胁迫的抵抗能力与普通细菌相似，但远低于普通细菌。Hsp21的表达使蓝藻获得了耐热性，特别是对致命高温的耐受性。研究结果表明，利用热休克蛋白基因工程技术增强植物耐高温能力是可能的。