Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands
Centre for Crop Systems Analysis, Wageningen University, 6700 AK, Wageningen, The Netherlands.
Plant Physiol. 2018 Feb;176(2):1247-1261. doi: 10.1104/pp.17.00779. Epub 2017 Sep 18.
We present a new simulation model of the reactions in the photosynthetic electron transport chain of C3 species. We show that including recent insights about the regulation of the thylakoid proton motive force, ATP/NADPH balancing mechanisms (cyclic and noncyclic alternative electron transport), and regulation of Rubisco activity leads to emergent behaviors that may affect the operation and regulation of photosynthesis under different dynamic environmental conditions. The model was parameterized with experimental results in the literature, with a focus on Arabidopsis (). A dataset was constructed from multiple sources, including measurements of steady-state and dynamic gas exchange, chlorophyll fluorescence, and absorbance spectroscopy under different light intensities and CO, to test predictions of the model under different experimental conditions. Simulations suggested that there are strong interactions between cyclic and noncyclic alternative electron transport and that an excess capacity for alternative electron transport is required to ensure adequate redox state and lumen pH. Furthermore, the model predicted that, under specific conditions, reduction of ferredoxin by plastoquinol is possible after a rapid increase in light intensity. Further analysis also revealed that the relationship between ATP synthesis and proton motive force was highly regulated by the concentrations of ATP, ADP, and inorganic phosphate, and this facilitated an increase in nonphotochemical quenching and proton motive force under conditions where metabolism was limiting, such as low CO, high light intensity, or combined high CO and high light intensity. The model may be used as an in silico platform for future research on the regulation of photosynthetic electron transport.
我们提出了一个新的 C3 物种光合作用电子传递链反应的模拟模型。我们表明，包括最近关于类囊体质子动力势调节、ATP/NADPH 平衡机制（环式和非环式交替电子传递）以及 Rubisco 活性调节的新见解，会导致一些新的行为出现，这些行为可能会影响不同动态环境条件下光合作用的运作和调节。该模型使用文献中的实验结果进行了参数化，重点是拟南芥（Arabidopsis）。从多个来源构建了一个数据集，包括在不同光强和 CO 下的稳态和动态气体交换、叶绿素荧光和吸收光谱的测量，以测试模型在不同实验条件下的预测。模拟表明，环式和非环式交替电子传递之间存在强烈的相互作用，并且需要有过剩的交替电子传递能力，以确保适当的氧化还原状态和腔室 pH。此外，该模型预测，在特定条件下，在光强快速增加后，质体醌还原铁氧还蛋白是可能的。进一步的分析还表明，ATP 合成与质子动力势之间的关系受到 ATP、ADP 和无机磷酸盐浓度的高度调节，这有助于在代谢受到限制的情况下，如低 CO、高光强或高 CO 和高光强的组合，增加非光化学猝灭和质子动力势。该模型可以作为未来光合作用电子传递调节研究的一个计算机模拟平台。
