Bilin-Dependent Photoacclimation in Chlamydomonas reinhardtii.
Bilin-Dependent Photoacclimation in Chlamydomonas reinhardtii.
复制标题
莱茵衣藻的 Bilin 依赖性光驯化。
DOI：
10.1105/tpc.17.00149
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发表时间：
2017
期刊：
影响因子：
11.6
通讯作者：
Lagarias J Clark
中科院分区：
文献类型：
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作者：
Wittkopp Tyler M;Schmollinger Stefan;Saroussi Shai;Hu Wei;Zhang Weiqing;Fan Qiuling;Gallaher Sean D;Leonard Michael T;Soubeyr;Eric;Basset Gilles J;Merchant Sabeeha S;Grossman Arthur R;Duanmu Deqiang;Lagarias J Clark
在陆地植物中，基于线性四吡咯(BLIN)的光敏色素传感器通过调节基因表达的大规模重新编程来优化光合作用的光捕获。但是，令人惊讶的是，许多绿藻基因组缺乏光敏色素基因。对绿藻衣藻血红素加氧酶突变体(Hmox1)的研究表明，叶绿体中胆碱的生物合成是适当调节核基因网络所必需的，该基因网络与暗到光的氧解毒有关。hmox1不能光自养生长，光适应能力差。我们认为，这些表型是由于光驯化过程中光系统I(PSI)反应中心、PSI电子受体5‘-单羟基叶醌和叶醌的积累减少，以及PSI和光系统II触角复合体的丢失所致。Hmox1突变体与叶绿素生物合成突变体的表型相似，但可以被外源胆绿素IXα拯救，胆绿素IX是由hmox1产生的胆碱。这种拯救不依赖于光合作用，并且强烈依赖于蓝光。对hmox1、基因互补的hmox1和化学挽救的hmox1的RNA-SEQ比较表明，hmox1突变体的四吡咯生物合成以及已知的光感受器和光合作用相关基因在转录水平上没有受到影响。我们认为，在光生衣藻中，一个基于BLIN的蓝光传感系统与一个基于BLIN的逆行信号通路一起进化，以确保一个强大的光合作用装置得以维持。
In land plants, linear tetrapyrrole (bilin)-based phytochrome photosensors optimize photosynthetic light capture by mediating massive reprogramming of gene expression. But, surprisingly, many green algal genomes lack phytochrome genes. Studies of the heme oxygenase mutant (hmox1) of the green algaChlamydomonas reinhardtiisuggest that bilin biosynthesis in plastids is essential for proper regulation of a nuclear gene network implicated in oxygen detoxification during dark-to-light transitions.hmox1cannot grow photoautotrophically and photoacclimates poorly to increased illumination. We show that these phenotypes are due to reduced accumulation of photosystem I (PSI) reaction centers, the PSI electron acceptors 5′-monohydroxyphylloquinone and phylloquinone, and the loss of PSI and photosystem II antennae complexes during photoacclimation. Thehmox1mutant resembles chlorophyll biosynthesis mutants phenotypically, but can be rescued by exogenous biliverdin IXα, the bilin produced by HMOX1. This rescue is independent of photosynthesis and is strongly dependent on blue light. RNA-seq comparisons ofhmox1, genetically complementedhmox1, and chemically rescuedhmox1reveal that tetrapyrrole biosynthesis and known photoreceptor and photosynthesis-related genes are not impacted in thehmox1mutant at the transcript level. We propose that a bilin-based, blue-light-sensing system within plastids evolved together with a bilin-based retrograde signaling pathway to ensure that a robust photosynthetic apparatus is sustained in light-grown Chlamydomonas.