Central metabolic fluxes in the endosperm of developing maize seeds and their implications for metabolic engineering
Central metabolic fluxes in the endosperm of developing maize seeds and their implications for metabolic engineering
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DOI：
10.1016/j.ymben.2010.10.002
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发表时间：
2011-01-01
影响因子：
8.4
通讯作者：
Shachar-Hill, Yair
中科院分区：
文献类型：
--
作者：
Alonso, Ana P.;Val, Dale L.;Shachar-Hill, Yair
用核培养进行的C-14标记实验表明，发育中的玉米胚乳比其他非光合组织（如向日葵和玉米胚）更有效地将母体提供的底物转化为生物量。为了表征玉米胚乳中的代谢通量，用c -13标记的葡萄糖将玉米籽粒标记为同位素稳态。通过核磁共振和气相色谱-质谱分析了游离代谢物和生物量的标记。在考虑到代谢活性穗轴提供的底物的标记后，通过计算机辅助建模量化了通过中心代谢的通量。通量图表明，51-69%的ATP用于生物质合成，高达47%的ATP用于底物循环。这些发现指出了提高产量和增加含油量的潜在工程目标，分别通过减少底物循环和增加丙酮酸激酶水平上对脂肪酸合成的可塑性碳的承诺。(C) 2010爱思唯尔公司版权所有。
C-14 labeling experiments performed with kernel cultures showed that developing maize endosperm is more efficient than other non-photosynthetic tissues such as sunflower and maize embryo sat converting maternally supplied substrates in to biomass. To characterize the metabolic fluxes in endosperm, maize kernels were labeled to isotopic steady state using C-13-labeled glucose. The resultant labeling in free metabolites and biomass was analyzed by NMR and GC-MS. After taking in to account the labeling of substrates supplied by the metabolically active cob, the fluxes through central metabolism were quantified by computer-aided modeling. The flux map indicates that 51-69% of the ATP produced is used for biomass synthesis and up to 47% is expended in substrate cycling. These findings point to potential engineering targets for improving yield and increasing oil contents by, respectively, reducing substrate cycling and increasing the commitment of plastidic carbon in to fatty acid synthesis at the level of pyruvate kinase. (C) 2010 Elsevier Inc. All rights reserved.