Mettler Tabea, Mühlhaus Timo, Hemme Dorothea, Schöttler Mark-Aurel, Rupprecht Jens, Idoine Adam, Veyel Daniel, Pal Sunil Kumar, Yaneva-Roder Liliya, Winck Flavia Vischi, Sommer Frederik, Vosloh Daniel, Seiwert Bettina, Erban Alexander, Burgos Asdrubal, Arvidsson Samuel, Schönfelder Stephanie, Arnold Anne, Günther Manuela, Krause Ursula, Lohse Marc, Kopka Joachim, Nikoloski Zoran, Mueller-Roeber Bernd, Willmitzer Lothar, Bock Ralph, Schroda Michael, Stitt Mark
Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam-Golm, Germany.
Plant Cell. 2014 Jun;26(6):2310-2350. doi: 10.1105/tpc.114.124537. Epub 2014 Jun 3.
We investigated the systems response of metabolism and growth after an increase in irradiance in the nonsaturating range in the algal model Chlamydomonas reinhardtii. In a three-step process, photosynthesis and the levels of metabolites increased immediately, growth increased after 10 to 15 min, and transcript and protein abundance responded by 40 and 120 to 240 min, respectively. In the first phase, starch and metabolites provided a transient buffer for carbon until growth increased. This uncouples photosynthesis from growth in a fluctuating light environment. In the first and second phases, rising metabolite levels and increased polysome loading drove an increase in fluxes. Most Calvin-Benson cycle (CBC) enzymes were substrate-limited in vivo, and strikingly, many were present at higher concentrations than their substrates, explaining how rising metabolite levels stimulate CBC flux. Rubisco, fructose-1,6-biosphosphatase, and seduheptulose-1,7-bisphosphatase were close to substrate saturation in vivo, and flux was increased by posttranslational activation. In the third phase, changes in abundance of particular proteins, including increases in plastidial ATP synthase and some CBC enzymes, relieved potential bottlenecks and readjusted protein allocation between different processes. Despite reasonable overall agreement between changes in transcript and protein abundance (R = 0.24), many proteins, including those in photosynthesis, changed independently of transcript abundance.
我们研究了莱茵衣藻这种藻类模型在非饱和光照范围内光照强度增加后，其代谢和生长的系统响应。在一个分三步的过程中，光合作用和代谢物水平立即增加，生长在10到15分钟后增加，转录本和蛋白质丰度分别在40分钟和120到240分钟后发生响应。在第一阶段，淀粉和代谢物为碳提供了一个短暂的缓冲，直到生长增加。这在波动的光照环境中将光合作用与生长解耦。在第一和第二阶段，代谢物水平的上升和多核糖体负载的增加推动了通量的增加。大多数卡尔文-本森循环（CBC）酶在体内受底物限制，而且引人注目的是，许多酶的浓度高于其底物，这解释了代谢物水平上升如何刺激CBC通量。核酮糖-1,5-二磷酸羧化酶/加氧酶、果糖-1,6-二磷酸酶和景天庚酮糖-1,7-二磷酸酶在体内接近底物饱和，通量通过翻译后激活而增加。在第三阶段，特定蛋白质丰度的变化，包括质体ATP合酶和一些CBC酶的增加，缓解了潜在的瓶颈，并重新调整了不同过程之间的蛋白质分配。尽管转录本和蛋白质丰度的变化总体上有合理的一致性（R = 0.24），但许多蛋白质，包括光合作用中的蛋白质，其变化与转录本丰度无关。
