Rubisco catalytic properties optimized for present and future climatic conditions
Rubisco catalytic properties optimized for present and future climatic conditions
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DOI：
10.1016/j.plantsci.2014.01.008
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发表时间：
2014-09-01
期刊：
影响因子：
5.2
通讯作者：
Flexas, J.
中科院分区：
文献类型：
--
作者：
Galmes, J.;Conesa, M. A.;Flexas, J.
由于其催化效率低，Rubisco是提高植物光合能力的最明显的改进目标。两个假设进行了测试，在目前的工作：（1）现有的Rubiscos具有最佳的动力学特性，以最大限度地提高光合作用的碳同化在现有的高等植物;（2）目前的知识允许建议的动力学特性的变化，使Rubiscos更适合于变化的条件下，叶绿体可能会发生气候变化。Rubisco的催化机制导致羧化的较高催化速率与对CO2的亲和力降低相关，因此对不同环境的选择涉及这两种性质之间的权衡。在这项研究中进行的模拟证实，Rubisco动力学的最优性取决于物种和环境条件。特别是，影响羧化（C-C）的CO2可用性或直接转移Rubisco和RuBP再生之间的光合限制的环境驱动因素决定了Rubisco动力学最适合于最大限度地提高CO2同化率。一般来说，最佳动力学的建模值反映了该领域的物种目前遇到的主要环境条件。在未来的气候条件下，光合CO2同化将受到限制RuBP再生，特别是在没有水分胁迫，[CO2]的最大上升和温度的最低增幅。在这些条件下，该模型预测最佳Rubisco应该具有高S-c/o和低K-cat（c）。(C)2014爱思唯尔爱尔兰有限公司版权所有。
Because of its catalytic inefficiencies, Rubisco is the most obvious target for improvement to enhance the photosynthetic capacity of plants. Two hypotheses are tested in the present work: (1) existing Rubiscos have optimal kinetic properties to maximize photosynthetic carbon assimilation in existing higher plants; (2) current knowledge allows proposal of changes to kinetic properties to make Rubiscos more suited to changed conditions in chloroplasts that are likely to occur with climate change. The catalytic mechanism of Rubisco results in higher catalytic rates of carboxylation being associated with decreased affinity for CO2, so that selection for different environments involves a trade-off between these two properties. The simulations performed in this study confirm that the optimality of Rubisco kinetics depends on the species and the environmental conditions. In particular, environmental drivers affecting the CO2 availability for carboxylation (C-c) or directly shifting the photosynthetic limitations between Rubisco and RuBP regeneration determine to what extend Rubisco kinetics are optimally suited to maximize CO2 assimilation rate. In general, modeled values for optimal kinetic reflect the predominant environmental conditions currently encountered by the species in the field. Under future climatic conditions, photosynthetic CO2 assimilation will be limited by RuBP-regeneration, especially in the absence of water stress, the largest rise in [CO2] and the lowest increases in temperature. Under these conditions, the model predicts that optimal Rubisco should have high S-c/o and low K-cat(c). (C) 2014 Elsevier Ireland Ltd. All rights reserved.