Deregulated Chlorophyll b Synthesis Reduces the Energy Transfer Rate Between Photosynthetic Pigments and Induces Photodamage in Arabidopsis thaliana
Deregulated Chlorophyll b Synthesis Reduces the Energy Transfer Rate Between Photosynthetic Pigments and Induces Photodamage in Arabidopsis thaliana
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DOI：
10.1093/pcp/pcq050
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发表时间：
2010-06-01
影响因子：
4.9
通讯作者：
Tanaka, Ayumi
中科院分区：
文献类型：
--
作者：
Sakuraba, Yasuhito;Yokono, Makio;Tanaka, Ayumi
Chl b 是陆地植物中主要的光捕获色素之一。叶绿素 b 的合成根据光照条件受到严格调节，以控制光系统的天线尺寸。 Chl b 的调节也会影响其分布，因为它优先出现在外围天线复合体中。然而，尚未通过实验证明植物在积累过量叶绿素 b 时如何应对环境条件。此前，我们培育了拟南芥转基因植物（简称BC植物），其中叶绿素b生物合成得到增强。在本研究中，我们分析了该植物在强光条件下的光合特性和全基因组基因表达，以了解叶绿素 b 生物合成失调的影响。 PSII 中叶绿素 a 分子之间的能量转移率下降，BC 植物中 H2O2 大量积累。微阵列分析显示，在 BC 植物中，一组参与花青素生物合成的基因下调，而另一组据报道对 H2O2 敏感的基因上调。我们还发现花青素水平较低，这与微阵列分析的结果一致。这些结果表明，叶绿素 b 的失调会导致严重的光损伤，并在强光照下改变基因表达谱。讨论了叶绿素 b 合成调节与叶绿素 b 和基因表达的正确定位的重要性。
Chl b is one of the major light-harvesting pigments in land plants. The synthesis of Chl b is strictly regulated in response to light conditions in order to control the antenna size of photosystems. Regulation of Chl b also affects its distribution as it occurs preferentially in the peripheral antenna complexes. However, it has not been experimentally shown how plants respond to environmental conditions when they accumulate excess Chl b. Previously, we produced an Arabidopsis transgenic plant (referred to as the BC plant) in which Chl b biosynthesis was enhanced. In this study, we analyzed the photosynthetic properties and genome-wide gene expression in this plant under high light conditions in order to understand the effects of deregulated Chl b biosynthesis. The energy transfer rates between Chl a molecules in PSII decreased and H2O2 accumulated extensively in the BC plant. Microarray analysis revealed that a group of genes involved in anthocyanin biosynthesis was down-regulated and that another group of genes, reported to be sensitive to H2O2, was up-regulated in the BC plant. We also found that anthocyanin levels were low, which was consistent with the results of the microarray analysis. These results indicate that deregulation of Chl b caused severe photodamage and altered gene expression profiles under strong illumination. The importance of the regulation of Chl b synthesis is discussed in relation to the correct localization of Chl b and gene expression.