Raw data for: Dual-cycle CO2 fixation enhances growth and lipid synthesis in Arabidopsis thaliana

Carbon fixation through the Calvin-Benson-Bassham (CBB) cycle accounts for the majority of CO2 uptake from the atmosphere. The CBB cycle generates C3 carbohydrates but is inefficient at producing acetyl-CoA (C2), which is the universal precursor for synthesizing lipids. Here, we introduce in Arabidopsis thaliana a new-to-nature CO2 fixing cycle, Malyl-coA-glycerate (McG) cycle, which, together with the CBB cycle, forms a dual-cycle CO2 fixation system. This cycle can fix one additional carbon by phosphoenolpyruvate carboxylase and convert the photorespiration product, glycolate, to acetyl-CoA. Plants with the McG cycle show enhanced protein abundance in their photosystems and enhanced photosystem II efficiency. McG plants had doubled CO2 fixation rates under atmospheric CO2, increased lipid production, pronounced growth enhancement, and tripled the seed yield.

通过卡尔文-本森-巴沙姆循环（Calvin-Benson-Bassham cycle，简称CBB循环）进行的碳固定，是大气二氧化碳摄取的主要途径。CBB循环可生成C3碳水化合物，但在合成作为脂质合成通用前体的乙酰辅酶A（acetyl-CoA）方面效率低下。本研究在拟南芥（Arabidopsis thaliana）中引入了一种全新的非天然固碳循环——苹果酰辅酶A-甘油酸（Malyl-coA-glycerate，简称McG）循环，该循环与CBB循环共同构成双循环固碳体系。该循环可通过磷酸烯醇式丙酮酸羧化酶（phosphoenolpyruvate carboxylase）额外固定一个碳原子，并将光呼吸产物乙醇酸（glycolate）转化为乙酰辅酶A。携带McG循环的拟南芥植株，其光系统的蛋白质丰度与光系统II（photosystem II）效率均得到提升。在大气CO₂条件下，McG循环植株的CO₂固定速率提升一倍，脂质生成量增加，生长显著增强，种子产量增至原来的三倍。