Maximizing photosynthetic efficiency and culture productivity in cyanobacteria upon minimizing the phycobilisome light-harvesting antenna size
Maximizing photosynthetic efficiency and culture productivity in cyanobacteria upon minimizing the phycobilisome light-harvesting antenna size
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DOI：
10.1016/j.bbabio.2014.07.009
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发表时间：
2014-10-01
影响因子：
4.3
通讯作者：
Melis, Anastasios
中科院分区：
文献类型：
--
作者：
Kirst, Henning;Formighieri, Cinzia;Melis, Anastasios
在用卡那霉素抗性盒替换CPC操纵子后产生集胞藻（蓝细菌）的藻蓝蛋白缺失突变体。与野生型（WT）的蓝-绿色表型相比，Delta cpc藻株（Delta cpc）表现出绿色表型，在625 nm处缺乏明显的藻蓝蛋白吸光度，并且与WT相比具有较低的Chl/细胞含量和较低的PSI/PSII反应中心比率。分子和遗传分析显示，集胞藻DNA的所有WT拷贝被转基因版本替换，从而实现基因组DNA同质性。生物化学分析表明，藻蓝蛋白α-和β-亚基的情况下，和卡那霉素抗性NPTI蛋白在三角洲CPC的过度表达。生理分析显示，约2倍，强度为光合作用的饱和度在三角洲CPC相比，WT。在有限的光照强度下，三角洲CPC的生长速度慢于WT。随着生长光照的增加，这种细胞复制率的差异逐渐减小。在约800 μ mol光子m（-2）S-1或更高时，观察到WT和Delta cpc的细胞复制速率相同，约为13 h。在模拟明亮的阳光和高细胞密度条件下的培养生产力分析表明，三角洲CPC的生物量积累是WT的1.57倍。因此，这项工作提供了第一时间的直接证据，截短的捕光天线（TLA）的概念在蓝藻中的适用性，需要大量的光合效率和生产力的提高后，最大限度地减少藻胆体捕光天线的大小。(C)2014爱思唯尔有限公司版权所有。
A phycocyanin-deletion mutant of Synechocystis (cyanobacteria) was generated upon replacement of the CPC-operon with a kanamycin resistance cassette. The Delta cpc transformant strains (Delta cpc) exhibited a green phenotype, compared to the blue-green of the wild type (WT), lacked the distinct phycocyanin absorbance at 625 nm, and had a lower Chl per cell content and a lower PSI/PSII reaction center ratio compared to the WT. Molecular and genetic analyses showed replacement of all WT copies of the Synechocystis DNA with the transgenic version, thereby achieving genomic DNA homoplasmy. Biochemical analyses showed the absence of the phycocyanin alpha- and beta-subunits, and the overexpression of the kanamycin resistance NPTI protein in the Delta cpc. Physiological analyses revealed a higher, by a factor of about 2, intensity for the saturation of photosynthesis in the Delta cpc compared to the WT. Under limiting intensities of illumination, growth of the Delta cpc was slower than that of the WT. This difference in the rate of cell duplication diminished gradually as growth irradiance increased. Identical rates of cell duplication of about 13 h for both WT and Delta cpc were observed at about 800 mu mol photons m(-2) S-1 or greater. Culture productivity analyses under simulated bright sunlight and high cell-density conditions showed that biomass accumulation by the Delta cpc was 1.57-times greater than that achieved by the WT. Thus, the work provides first-time direct evidence of the applicability of the Truncated Light-harvesting Antenna (TLA)-concept in cyanobacteria, entailing substantial improvements in the photosynthetic efficiency and productivity of mass cultures upon minimizing the phycobilisome light-harvesting antenna size. (C) 2014 Elsevier B.V. All rights reserved.