Metabolic flux maps comparing the effect of temperature on protein and oil biosynthesis in developing soybean cotyledons
Metabolic flux maps comparing the effect of temperature on protein and oil biosynthesis in developing soybean cotyledons
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DOI：
10.1111/j.1365-3040.2008.01781.x
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发表时间：
2008-04-01
影响因子：
7.3
通讯作者：
Shanks, Jacqueline. V.
中科院分区：
文献类型：
--
作者：
Iyer, Vidya V.;Sriram, Ganesh;Shanks, Jacqueline. V.
由 C-13 代谢通量分析 (C-13 MFA) 开发的代谢通量图是评估生物系统对遗传或环境扰动的响应以及识别可能的代谢工程目标的有效工具。实验处理的目的是区分体外孵化前和孵化期间的温度对发育中大豆初级代谢的影响。生物量积累随着温度的增加而增加，碳分配成脂质也随着温度的增加而增加。当子叶从最佳生长温度转移到体外培养中的不同温度时，相对于蔗糖摄入量，通过质体氧化戊糖磷酸途径 (pgl(P)) 的通量保持相当恒定 [类似于 56% (+/- 24%)]，这表明在这些条件下存在刚性节点。然而，当植物生长温度变化并在相同温度（与植物）体外培养时，pgl（P）通量范围为蔗糖摄入量的57％至77％，表明这种情况的灵活节点。由质体苹果酸酶（me(P)）、胞质磷酸烯醇丙酮酸（PEP）羧化酶和苹果酸（Mal）转运蛋白催化的回补反应从胞质溶胶到线粒体的碳通量随温度变化很大，并且对碳从质体丙酮酸（Pyr）库分配成蛋白质和油有直接影响。体外培养的这些结果表明，发育早期阶段的温度对于建立通过中心碳代谢的某些成分的通量能力具有主导作用。
Metabolic flux maps developed from C-13 metabolic flux analysis (C-13 MFA) are effective tools for assessing the response of biological systems to genetic or environmental perturbations, and for identifying possible metabolic engineering targets. Experimental treatments were designed to distinguish between temperature effects prior to, and during incubation in vitro, on primary metabolism in developing soybeans. Biomass accumulation increased with temperature as did carbon partitioning into lipids. The flux through the plastidic oxidative pentose phosphate pathway (pgl(P)) relative to sucrose intake remained fairly constant [similar to 56% (+/- 24%)] when cotyledons were transferred from an optimum growth temperature to varying temperatures in in vitro culture, signifying a rigid node under these conditions. However, pgl(P) flux ranged from 57 to 77% of sucrose intake when growth temperature in planta varied and were cultured in vitro at the same temperature (as the plant), indicating a flexible node for this case. The carbon flux through the anaplerotic reactions catalysed by plastidic malic enzyme (me(P)), cytosolic phosphoenolpyruvate (PEP) carboxylase and the malate (Mal) transporter from the cytosol to mitochondrion varied dramatically with temperature and had a direct influence on the carbon partitioning into protein and oil from the plastidic pyruvate (Pyr) pool. These results of the in vitro culture indicate that temperature during early stages of development has a dominant effect on establishing capacity for flux through certain components of central carbon metabolism.