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Regulation of photosystem formation : A flexibility of energy-conversion system in thylakoids responding to environments

光系统形成的调节：类囊体能量转换系统对环境响应的灵活性

基本信息

批准号：
04454016
负责人：
FUJITA Yoshihiko
金额：
$ 3.71万
依托单位：
National Institute for Basic Biology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

The study aimed to make clear the characteristics of PSI/PSII variation found with photosynthesis of cyanophytes. The characterization was made in three aspects. The first was analysis of molecular mechanism for requlation of PSI formation. Most effort was paid focusing on identification of the target step (s) in PSI formation. Analysis of steps for apoprotein synthesis revealed that the regulation occurs at translation level ; the translation is suppressed under PSI light and is released from suppression under PSII light. The regulation was found to correlate with Chl a biosynthesis. We suspect that PSI formation is regulated at the step (s) for chl a installation into apoprotein.In the study of the second aspect, we examined PSI/PSII variation with algal organisms other than cyanophytes. We examined with the red alga Porphyra yezoensis and the green alga Chlamydomonas reinhardtii. Results indicated that PSI/PSII variation occurs in these organisms in a similar manner to that in cyanophytes. PSI/PSII variation in different phyla indicates that the regulatory mechanism of this type is a common ability of oxygenic photosynthesis of green plants.Our study for the third aspect was made for comparison of PSI/PSII variation induced by chromatic light with the variation induced by environmental stresses other than light regime. CO_2- and Na^+-stresses cause a biassed state of ETS as similar to that caused by light shift from PSI light to PSII light. As expected, the two environmental stresses caused an increase in PSI/PSII ratio, like the light shift. Results clearly indicate that PSI/PSII ratio is regulated in response to the state of ETS and support our previous hypothesis.

本研究旨在明确蓝藻光合作用过程中PSI/PSII的变化特征。主要从三个方面进行了描述。第一部分是PSI形成调控的分子机制分析。大部分的努力集中在识别PSI形成的目标步骤上。对载脂蛋白合成步骤的分析表明，这种调节发生在翻译水平; PSI光下翻译被抑制，而PSII光下翻译被解除抑制。这种调节与叶绿素a的生物合成有关。在第二个方面的研究中，我们检测了除蓝藻外的藻类生物的PSI/PSII的变化。我们用红色条斑紫菜和绿色莱茵衣藻进行了研究。结果表明，PSI/PSII的变化发生在这些生物中以类似的方式在蓝藻。PSI/PSII在不同门中的变化表明这种类型的调节机制是绿色植物光合作用的共同能力。CO_2-和Na^+-胁迫使ETS处于偏态，这与光从PSI光向PSII光转换所引起的偏态相似。正如预期的那样，这两种环境胁迫导致PSI/PSII比值增加，如光移。结果清楚地表明，PSI/PSII的比例调节在ETS的状态，并支持我们以前的假设。