Phototropin connects blue light perception to starch metabolism in green algae

In photosynthetic organisms light acts as an environmental signal to control their development and physiology, and as energy source to drive the conversion of CO2 into carbohydrates used for growth or storage. The main storage carbohydrate in green algae is starch, which accumulates during the day and is broken down at night to meet cellular energy demands. The signalling role of light quality in the regulation of starch accumulation remains unexplored. Here, we report that in the model green alga Chlamydomonas reinhardtii blue light perceived by the photoreceptor PHOTOTROPIN suppresses starch accumulation. To gain more insight into the molecular mechanism underlying the PHOT-mediated light perception and starch accumulation, we applied we applied mass spectrometry (MS)-based quantitative proteomics to compare WT and phot cells grown in asynchronous photoautotrophic conditions under low light.

在光合生物中，光既是调控其发育与生理状态的环境信号，也是驱动二氧化碳（CO₂）转化为供生长或储存使用的碳水化合物的能量来源。绿藻的主要储存性碳水化合物为淀粉（starch），其会在日间积累、夜间降解以满足细胞的能量需求。光质在调控淀粉积累过程中的信号传导作用，目前仍未得到深入研究。本研究发现，在模式绿藻莱茵衣藻（Chlamydomonas reinhardtii）中，由光受体向光素（PHOTOTROPIN）感知的蓝光会抑制淀粉积累。为深入解析向光素介导的光感知与淀粉积累的分子机制，我们采用基于质谱（mass spectrometry，MS）的定量蛋白质组学技术，对比了在低光下非同步化光合自养培养条件下生长的野生型（wild type，WT）与phot突变体细胞的蛋白表达差异。