Characterization of the genetic requirements for photoautotrophic growth under fluctuating light intensities, using novel high-throughput genomics approaches in the green alga Chlamydomonas reinhardtii

太阳光驱动光合作用。光合作用的生物体在这种能源的可获得性方面经历了很大的波动。它们对光强变化的快速适应对于最佳的光合作用产量是重要的。导致光合作用真核生物适应的过程包括感知和调节光合作用电子传输链的依赖于光的活动的机制。这些驯化过程中涉及的分子因素已经通过光合作用参数改变的突变体的遗传筛选得到了鉴定。作为DFG的一员，我建议通过对绿藻Chlamydomonas rehardtii进行前沿的全基因组筛选，系统地鉴定在高波动光下最佳光自养生长所需的重要成分。数十万个突变体的生长速度将使用汇集策略进行测量，其中每个突变体都由唯一的DNA条形码识别。与对照相比，缺乏快速适应反应的突变体在波动光条件下的生长缺陷将被揭示出来。我认为类囊体膜上的离子通道对于在波动的光照条件下的生长可能是特别重要的，因为它们在消散质子驱动力中依赖于光的电子成分。如果在筛选中发现了离子通道，我将通过衣藻突变体的光谱分析和蛋白质的生化分析来表征它们的功能作用。

Sun light drives photosynthesis. Photosynthetic organisms experience substantial fluctuations in the availability of this energy source. Their rapid acclimation to changes in light intensity is important for optimal photosynthesis yield. Processes that lead to the acclimation of photosynthetic eukaryotes include mechanisms that sense and regulate the light dependent activity of the photosynthetic electron transport chain. Molecular factors involved in these acclimating processes have been identified with genetic screens for mutants with altered photosynthesis parameters. Some of these mutants show specific growth defects when grown under highly fluctuating light intensities.As a DFG fellow, I propose to systematically identify components important for optimum photoautotrophic growth under highly fluctuating light by performing a cutting-edge genome-wide screen in the green alga Chlamydomonas reinhardtii. Growth rates of hundreds of thousands of mutants will be measured using a pooled strategy where each mutant is identified by a unique DNA barcode. Mutants deficient in rapid acclimation responses will be revealed by their growth defects under fluctuating light conditions, in comparison to a control condition. I hope that this screen will uncover a variety of previously unappreciated pathways and components with roles in short-term acclimation to changes in light intensity.I hypothesize that ion channels in the thylakoid membrane may be specifically important for growth under fluctuating light conditions, because of their role in dissipating the light dependent electric component of the proton motive force. If ion channels are identified in the screen, I will characterize their functional role with spectroscopic analyses of Chlamydomonas mutants and biochemical analyses of the proteins.