Sweetlove Lee J, Kossmann Jens, Riesmeier Jörg W, Trethewey Richard N, Hill Steven A
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK, andMax-Planck-Institut für Molekulare Pflanzenphysiologie, Karl Liebknecht Str. 25, 14476 Golm, Germany.
Plant J. 1998 Sep;15(5):697-706. doi: 10.1046/j.1365-313x.1998.00247.x.
We have used top-down metabolic control analysis to investigate the control of carbon flux through potato (Solanum tuberosum) plants during tuberisation. The metabolism of the potato plant was divided into two blocks of reactions (the source and sink blocks) that communicate through the leaf apoplastic sucrose pool. Flux was measured as the transfer of C from CO to the tuber. Flux and apoplastic sucrose concentration were varied either by changing the light intensity or using transgenic manipulations that specifically affect the source or sink blocks, and elasticity coefficients were measured. We have provided evidence in support of our assumption that apoplastic sucrose is the only communicating metabolite between the source and sink blocks. The elasticity coefficients were used to calculate the flux control coefficients of the source and sink blocks, which were 0.8 and 0.2, respectively. This work suggests that the best strategy for the manipulation of tuber yield in potato will involve increases in photosynthetic capacity, rather than sink metabolism.
我们采用自上而下的代谢控制分析方法，研究了马铃薯（Solanum tuberosum）块茎形成过程中碳通量的控制情况。马铃薯植株的代谢被分为两个反应模块（源模块和库模块），它们通过叶片质外体蔗糖库进行联系。通量以碳从CO₂转移到块茎中的量来衡量。通过改变光照强度或使用特异性影响源模块或库模块的转基因操作来改变通量和质外体蔗糖浓度，并测定弹性系数。我们已提供证据支持我们的假设，即质外体蔗糖是源模块和库模块之间唯一的联系代谢物。弹性系数用于计算源模块和库模块的通量控制系数，分别为0.8和0.2。这项工作表明，调控马铃薯块茎产量的最佳策略将涉及提高光合能力，而非库代谢。
