PDF(Pubmed)
Abstract：
Cyanobacteria play a key role in primary production in both oceans and fresh waters and hold great potential for sustainable production of a large number of commodities. During their life, cyanobacteria cells need to acclimate to a multitude of challenges, including shifts in intensity and quality of incident light. Despite our increasing understanding of metabolic regulation under various light regimes, detailed insight into fitness advantages and limitations under shifting light quality remains underexplored. Here, we study photo-physiological acclimation in the cyanobacterium Synechocystis sp. PCC 6803 throughout the photosynthetically active radiation (PAR) range. Using light emitting diodes (LEDs) with qualitatively different narrow spectra, we describe wavelength dependence of light capture, electron transport and energy transduction to main cellular pools. In addition, we describe processes that fine-tune light capture, such as state transitions, or the efficiency of energy transfer from phycobilisomes to photosystems (PS). We show that growth was the most limited under blue light due to inefficient light harvesting, and that many cellular processes are tightly linked to the redox state of the plastoquinone (PQ) pool, which was the most reduced under red light. The PSI-to-PSII ratio was low under blue photons, however, it was not the main growth-limiting factor, since it was even more reduced under violet and near far-red lights, where Synechocystis grew faster compared to blue light. Our results provide insight into the spectral dependence of phototrophic growth and can provide the foundation for future studies of molecular mechanisms underlying light acclimation in cyanobacteria, leading to light optimization in controlled cultivations.
摘要：
蓝藻在海洋和淡水的初级生产中起着关键作用，并具有可持续生产大量商品的巨大潜力。在他们的生活中,蓝藻细胞需要适应多种挑战，包括入射光的强度和质量的变化。尽管我们越来越了解各种光照条件下的代谢调节，关于光质变化下的健身优势和局限性的详细见解仍未得到充分探索。这里,我们研究了蓝细菌集胞藻的光生理适应。在整个光合有效辐射(PAR)范围内的PCC6803。使用具有定性不同窄光谱的发光二极管（LED），我们描述了光捕获的波长依赖性，电子传输和能量转移到主要的细胞池。此外,我们描述了微调光捕获的过程，例如状态转换，或从藻胆体到光系统（PS）的能量转移效率。我们表明，由于低效的光收集，在蓝光下生长是最有限的，并且许多细胞过程与质体醌（PQ）池的氧化还原状态紧密相关，在红灯下减少最多。在蓝色光子下，PSI与PSII的比率较低，然而,它不是主要的增长限制因素，因为在紫罗兰色和近红光下，它甚至减少了，与蓝光相比，集胞藻生长更快。我们的结果提供了对光养生长的光谱依赖性的见解，并可以为未来研究蓝细菌光适应的分子机制奠定基础。导致受控栽培中的光优化。
