Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg, Potsdam-Golm, Germany.
School of Molecular Sciences, The University of Western Australia, Crawley WA, Australia.
J Exp Bot. 2019 Mar 27;70(6):1843-1858. doi: 10.1093/jxb/erz051.
Low atmospheric CO2 in recent geological time led to the evolution of carbon-concentrating mechanisms (CCMs) such as C4 photosynthesis in >65 terrestrial plant lineages. We know little about the impact of low CO2 on the Calvin-Benson cycle (CBC) in C3 species that did not evolve CCMs, representing >90% of terrestrial plant species. Metabolite profiling provides a top-down strategy to investigate the operational balance in a pathway. We profiled CBC intermediates in a panel of C4 (Zea mays, Setaria viridis, Flaveria bidentis, and F. trinervia) and C3 species (Oryza sativa, Triticium aestivum, Arabidopsis thaliana, Nicotiana tabacum, and Manihot esculenta). Principal component analysis revealed differences between C4 and C3 species that were driven by many metabolites, including lower ribulose 1,5-bisphosphate in C4 species. Strikingly, there was also considerable variation between C3 species. This was partly due to different chlorophyll and protein contents, but mainly to differences in relative levels of metabolites. Correlation analysis indicated that one contributory factor was the balance between fructose-1,6-bisphosphatase, sedoheptulose-1,7-bisphosphatase, phosphoribulokinase, and Rubisco. Our results point to the CBC having experienced different evolutionary trajectories in C3 species since the ancestors of modern plant lineages diverged. They underline the need to understand CBC operation in a wide range of species.
在最近的地质时期，大气中 CO2 含量较低，导致了碳浓缩机制（CCMs）的进化，如 65 个以上的陆地植物谱系中的 C4 光合作用。我们对 CO2 含量较低对没有进化出 CCM 的 C3 物种的卡尔文-本森循环（CBC）的影响知之甚少，这些 C3 物种代表了超过 90%的陆地植物物种。代谢物谱分析提供了一种自上而下的策略来研究途径中的操作平衡。我们对一组 C4（玉米、柳枝稷、斑叶狗尾草和三齿猪毛菜）和 C3 物种（水稻、小麦、拟南芥、烟草和木薯）的 CBC 中间产物进行了谱分析。主成分分析揭示了 C4 和 C3 物种之间的差异，这些差异是由许多代谢物驱动的，包括 C4 物种中较低的核酮糖 1,5-二磷酸。引人注目的是，C3 物种之间也存在相当大的差异。这部分是由于叶绿素和蛋白质含量的不同，但主要是由于代谢物相对水平的不同。相关分析表明，一个促成因素是果糖-1,6-二磷酸酶、景天庚酮糖-1,7-二磷酸酶、磷酸核糖激酶和 Rubisco 之间的平衡。我们的结果表明，自现代植物谱系的祖先分化以来，C3 物种的 CBC 经历了不同的进化轨迹。它们强调了需要在广泛的物种中理解 CBC 的运作。
