Optimal coordination and reorganization of photosynthetic properties in C 4 grasses
Optimal coordination and reorganization of photosynthetic properties in C 4 grasses
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C 4 草光合特性的优化协调和重组
DOI：
10.1111/pce.14506
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Helliker, Brent
中科院分区：
文献类型：
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作者：
Zhou, Haoran;Akçay, Erol;Helliker, Brent
牧草C4光合作用的每一次独立进化都需要重组叶片内的Calvin-Benson循环(CB-循环)，以及C4循环酶与CB-循环的协调，以最大限度地吸收二氧化碳。考虑到C4进化的大量时间，我们假设(I)C4和C3亲缘关系密切的家系内部和之间存在性状差异，(Ii)C4进化后性状的趋势产生了C4的优化，以及(Iii)CB周期和C4周期之间协调趋势的存在/不存在提供了关于选择强度的信息。为了解决这些假设，我们使用了最优化模型、生理测量和系统发育比较分析的组合。在C4进化后，光合作用得到优化，导致C4谱系内最大同化、电子传递、Rubisco羧化、磷酸烯醇式丙酮酸羧化酶和叶绿素的多样性。理论和测量都表明，C4中的光反应与CB循环的比率(Jatpmax/Vcmax)高于C3。CB循环、光反应和C4循环之间的光合作用协调没有进化趋势，这表明协调的初始选择很强。对于200 ppm的二氧化碳，CB-C4循环的配位(Vpmax/Vcmax)是最优的，而不是在当前条件下。我们的模型表明，高于最优的Vpmax/Vcmax对同化的影响最小，从而减少了最近的选择以降低Vpmax/Vcmax。
Each of >20 independent evolutions of C4photosynthesis in grasses required reorganization of the Calvin–Benson‐cycle (CB‐cycle) within the leaf, along with coordination of C4‐cycle enzymes with the CB‐cycle to maximize CO2assimilation. Considering the vast amount of time over which C4evolved, we hypothesized (i) trait divergences exist within and across lineages with both C4and closely related C3grasses, (ii) trends in traits after C4evolution yield the optimization of C4through time, and (iii) the presence/absence of trends in coordination between the CB‐cycle and C4‐cycle provides information on the strength of selection. To address these hypotheses, we used a combination of optimality modelling, physiological measurements and phylogenetic‐comparative‐analysis. Photosynthesis was optimized after the evolution of C4causing diversification in maximal assimilation, electron transport, Rubisco carboxylation, phosphoenolpyruvate carboxylase and chlorophyll within C4lineages. Both theory and measurements indicated a higher light‐reaction to CB‐cycle ratio (Jatpmax/Vcmax) in C4than C3. There were no evolutionary trends with photosynthetic coordination between the CB‐cycle, light reactions and the C4‐cycle, suggesting strong initial selection for coordination. The coordination of CB‐C4‐cycles (Vpmax/Vcmax) was optimal for CO2of 200 ppm, not to current conditions. Our model indicated that a higher than optimalVpmax/Vcmaxaffects assimilation minimally, thus lessening recent selection to decreaseVpmax/Vcmax.