The environmental plasticity and ecological genomics of the cyanobacterial CO2 concentrating mechanism
The environmental plasticity and ecological genomics of the cyanobacterial CO2 concentrating mechanism
复制标题
DOI：
10.1093/jxb/eri286
复制
发表时间：
2006-01-01
影响因子：
6.9
通讯作者：
Woodger, FJ
中科院分区：
文献类型：
--
作者：
Badger, MR;Price, GD;Woodger, FJ
在所有光合生物的生长环境中，蓝细菌可能表现出最广泛的多样性。它们存在于寒冷和炎热，碱性和酸性，海洋，淡水，盐水，陆地和共生环境中。除此之外，它们至少在25亿年前起源于地球，并经历了O-2急剧增加，CO2下降和温度变化的时期。它们在进化过程中和当前环境中面临的关键问题之一是CO2的捕获及其在光合作用中被Rubisco有效利用。对这一挑战的核心反应是开发一种可适应各种环境限制的CO2浓缩机制（CCM）。该CCM有两个主要功能要素。首先，细胞内的羧基体蛋白微体（CO2升高的位点）中含有Rubisco，其次，存在几种无机碳（Ci）转运蛋白，其在细胞内递送HCO 3。蓝细菌既表现出物种适应又表现出驯化机制。在物种之间，每个基因组中的Ci转运蛋白套件、羧基体结构的性质和碳酸酐酶的功能作用存在差异。在一个物种内，不同的CCM活动可以诱导取决于在环境中的Ci的可用性。这种驯化主要是基于诱导多种Ci转运蛋白，其对CO2或HCO 3-作为底物具有不同的亲和力和特异性。这些功能进行了讨论，我们目前的知识的不同阵列的蓝藻和它们的生态环境的基因组序列。
Cyanobacteria probably exhibit the widest range of diversity in growth habitats of all photosynthetic organisms. They are found in cold and hot, alkaline and acidic, marine, freshwater, saline, terrestrial, and symbiotic environments. In addition to this, they originated on earth at least 2.5 billion years ago and have evolved through periods of dramatic O-2 increases, CO2 declines, and temperature changes. One of the key problems they have faced through evolution and in their current environments is the capture of CO2 and its efficient use by Rubisco in photosynthesis. A central response to this challenge has been the development of a CO2 concentrating mechanism (CCM) that can be adapted to various environmental limitations. There are two primary functional elements of this CCM. Firstly, the containment of Rubisco in carboxysome protein microbodies within the cell (the sites of CO2 elevation), and, secondly, the presence of several inorganic carbon (Ci) transporters that deliver HCO3- intracellularly. Cyanobacteria show both species adaptation and acclimation of this mechanism. Between species, there are differences in the suites of Ci transporters in each genome, the nature of the carboxysome structures and the functional roles of carbonic anhydrases. Within a species, different CCM activities can be induced depending on the Ci availability in the environment. This acclimation is largely based on the induction of multiple Ci transporters with different affinities and specificities for either CO2 or HCO3- as substrates. These features are discussed in relation to our current knowledge of the genomic sequences of a diverse array of cyanobacteria and their ecological environments.