Diverse Chromatic Acclimation Processes Regulating Phycoerythrocyanin and Rod-Shaped Phycobilisome in Cyanobacteria
Diverse Chromatic Acclimation Processes Regulating Phycoerythrocyanin and Rod-Shaped Phycobilisome in Cyanobacteria
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DOI：
10.1016/j.molp.2019.02.010
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发表时间：
2019-05-06
期刊：
影响因子：
27.5
通讯作者：
Eki, Toshihiko
中科院分区：
文献类型：
--
作者：
Hirose, Yuu;Song Chihong;Eki, Toshihiko
蓝藻在不同的光环境下进化出了多种光适应过程来进行光合产氧。色彩驯化（CA）是一种被广泛认可的和生态上重要的光驯化类型，蓝细菌通过改变被称为藻胆体的超分子天线复合物的吸收光的颜色。迄今为止，已经表征了几种CA变体，其调节半盘状形式的藻胆体内的绿色吸收藻红蛋白（PE）和/或红色吸收藻蓝蛋白（PC）。在这项研究中，我们确定了一个独特的CA调控基因簇编码黄绿色吸收藻红蓝蛋白（PEC）和杆膜连接蛋白（CpcL）的杆状形式的藻胆体。利用蓝细菌Leptolyngbya sp. PCC 6406，我们揭示了调节PEC（CA 7）和杆状藻胆体（CA 0）的新CA变体，它们分别最大化黄绿光捕获能力和平衡光系统的激发。分析CA基因簇在445个蓝藻基因组中的分布，发现8个CA变体响应于绿色和红光，这是基于PEC，PE，cpcL和CA光传感器基因的存在进行分类。系统发育分析进一步表明，CA 7的出现是一个单一的事件，并在异囊菌株之前，而CAO的收购发生多次。总之，这些结果提供了新的见解的多样性和复杂的蓝藻光适应机制的演变。
Cyanobacteria have evolved various photoacclimation processes to perform oxygenic photosynthesis under different light environments. Chromatic acclimation (CA) is a widely recognized and ecologically important type of photoacclimation, whereby cyanobacteria alter the absorbing light colors of a supermolecular antenna complex called the phycobilisome. To date, several CA variants that regulate the green-absorbing phycoerythrin (PE) and/or the red-absorbing phycocyanin (PC) within the hemi-discoidal form of phycobilisome have been characterized. In this study, we identified a unique CA regulatory gene cluster encoding yellow-green-absorbing phycoerythrocyanin (PEC) and a rod-membrane linker protein (CpcL) for the rod-shaped form of phycobilisome. Using the cyanobacterium Leptolyngbya sp. PCC 6406, we revealed novel CA variants regulating PEC (CA7) and the rod-shaped phycobilisome (CA0), which maximize yellow-green light-harvesting capacity and balance the excitation of photosystems, respectively. Analysis of the distribution of CA gene clusters in 445 cyanobacteria genomes revealed eight CA variants responding to green and red light, which are classified based on the presence of PEC, PE, cpcL, and CA photosensor genes. Phylogenetic analysis further suggested that the emergence of CA7 was a single event and preceded that of heterocystous strains, whereas the acquisition of CAO occurred multiple times. Taken together, these results offer novel insights into the diversity and evolution of the complex cyanobacterial photoacclimation mechanisms.