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。光合生物在这种能源的可用性方面经历了很大的波动。它们对光强变化的快速适应对获得最佳光合产量至关重要。导致光合作用的真核生物适应的过程包括感知和调节光合作用电子传递链的光依赖性活动的机制。参与这些适应过程的分子因素已经被确定为具有改变光合参数的突变体的遗传筛选。其中一些突变体在高度波动的光强下生长时表现出特定的生长缺陷。作为DFG的一名研究员，我建议通过对莱茵衣藻（Chlamydomonas reinhardtii）进行尖端的全基因组筛选，系统地识别在高度波动光下最佳光自养生长的重要成分。成千上万的突变体的生长速度将使用一种混合策略来测量，其中每个突变体都由一个独特的DNA条形码识别。与对照条件相比，在波动光照条件下的生长缺陷揭示了缺乏快速驯化反应的突变体。我希望这个屏幕将揭示各种以前未被重视的途径和成分，这些途径和成分在短期适应光强变化中发挥作用。我假设类囊体膜中的离子通道可能对波动光条件下的生长特别重要，因为它们在消散质子动力的光依赖电成分中起作用。如果在屏幕上识别出离子通道，我将通过突变衣藻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.