SynthSys and School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
Department of Biology, Institute of Molecular Plant Biology, ETH Zurich, Zurich, Switzerland.
Mol Syst Biol. 2018 Mar 1;14(3):e7962. doi: 10.15252/msb.20177962.
Plants respond to seasonal cues such as the photoperiod, to adapt to current conditions and to prepare for environmental changes in the season to come. To assess photoperiodic responses at the protein level, we quantified the proteome of the model plant by mass spectrometry across four photoperiods. This revealed coordinated changes of abundance in proteins of photosynthesis, primary and secondary metabolism, including pigment biosynthesis, consistent with higher metabolic activity in long photoperiods. Higher translation rates in the day than the night likely contribute to these changes, via an interaction with rhythmic changes in RNA abundance. Photoperiodic control of protein levels might be greatest only if high translation rates coincide with high transcript levels in some photoperiods. We term this proposed mechanism "translational coincidence", mathematically model its components, and demonstrate its effect on the proteome. Datasets from a green alga and a cyanobacterium suggest that translational coincidence contributes to seasonal control of the proteome in many phototrophic organisms. This may explain why many transcripts but not their cognate proteins exhibit diurnal rhythms.
植物会对光周期等季节性线索做出反应，以适应当前的环境条件，并为即将到来的季节环境变化做好准备。为了在蛋白质水平上评估光周期反应，我们通过质谱法在四个光周期内对模式植物的蛋白质组进行了定量分析。这揭示了光合作用、初级和次级代谢物（包括色素生物合成）中蛋白质丰度的协调变化，与长光周期下更高的代谢活性一致。由于与 RNA 丰度的节律变化相互作用，白天的翻译速率可能高于夜间，从而导致这些变化。只有在某些光周期中，高翻译速率与高转录水平同时发生时，蛋白质水平的光周期控制才可能最大。我们将这种拟议的机制称为“翻译偶联”，对其组成部分进行了数学建模，并证明了其对蛋白质组的影响。来自绿藻和蓝藻的数据集表明，翻译偶联有助于许多光养生物季节性控制蛋白质组。这可能解释了为什么许多转录物而不是其同源蛋白质表现出昼夜节律。
