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Study on the effects of temperature stress on plants and the acclimation mechanism

温度胁迫对植物的影响及驯化机制研究

基本信息

批准号：
11440238
负责人：
KAZUHIKO Satoh
金额：
$ 9.6万
依托单位：
Himeji Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

High-temperature-induced inhibition of oxygen evolution was due to release of the Mn-stabilizing 33 kDa protein from the photosystem (PS) II complex. We found that semipermeability of thylakoid membranes is also lost at temperatures at which the oxygen evolution activity is inhibited. Decreases in the fluidity of isolated thylakoids by the addition of cholesterol also decreased the thermo-sensitivity of oxygen evolution reaction. Thermo-stabilities of the semipermeability and oxygen evolution changed in parallel in wheat and Arabidopsis grown at 15, 25, and 35 ℃. These results suggest that changes in the ion composition of thylakoid lumen cause release of the 33 kDa protein form the PSII complex.We also found that cyclic electron flow around PSI is accelerated by high temperatures. Experiments using various inhibitors and an ndhB-less mutant of tobacco showed that not NAD(P)H dehydrogenase but a flavin enzyme is related to this phenomenon.Another important result was obtained using Synechocystis sp. PCC6803, a cyanobacterium, the CP47 protein of which is His-tagged. Oxygen-evolving PSII core complexes were easily isolated and purified using this mutant. The isolated thylakoid membranes from the 25 ℃-grown cells (25 ℃-thylakoids) showed less thermo-stability than those obtained from the 35 ℃-grown cells (25 ℃ -thylakoids). On the other hand, the core complexes isolated from the 25 ℃-grown cells showed the same thermostability as did the 35 ℃-grown cells. Incorporation of the PSII core complexes into liposomes made from the lipids of the 25 ℃-thylakoids or of the 35 ℃-thylakoids showed that the thermostability of the PSII reaction center activity is determined by the characteristics of the thylakoid lipids.

高温诱导的抑制氧的释放是由于锰稳定33 kDa的蛋白质从光系统（PS）II复合物的释放。我们发现，类囊体膜的半透性也失去了在温度下，在该温度下的析氧活性被抑制。胆固醇的加入降低了类囊体的流动性，也降低了放氧反应的温度敏感性。在15、25和35 ℃下，小麦和拟南芥的半透性和放氧热稳定性平行变化。这些结果表明，类囊体腔离子组成的变化引起PSII复合物中33 kDa蛋白的释放，高温也加速了PSI周围的循环电子流。使用各种抑制剂和烟草的ndhB缺失突变体的实验表明，与这种现象有关的不是NAD（P）H脱氢酶，而是黄素酶。放氧PSII核心复合物很容易分离和纯化使用此突变体。从25 ℃培养的细胞中分离的类囊体膜（25 ℃-类囊体）的热稳定性低于从35 ℃培养的细胞中分离的类囊体膜（25 ℃ -类囊体）。另一方面，从25 ℃生长的细胞中分离的核心复合物显示出与35 ℃生长的细胞相同的热稳定性。将PSII核心复合物掺入由25 ℃类囊体或35 ℃类囊体脂质制成的脂质体中表明，PSII反应中心活性的热稳定性由类囊体脂质的特性决定。