Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Seville, Spain.
Plant Cell. 2014 Feb;26(2):565-84. doi: 10.1105/tpc.114.122721. Epub 2014 Feb 21.
Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process.
开花是一个需要大量资源的关键过程。碳代谢必须通过一种控制机制与发育相协调，这种机制可以优化植物任何生理需求和生长阶段的适应性。然而，在花发育转变过程中，糖的分配是如何被控制的还不清楚。最近，研究证明CONSTANS (CO) 同源物（Cr-CO）在调控绿藻莱茵衣藻光周期反应及其对淀粉代谢的影响中起着重要作用。在这项工作中，我们表明，拟南芥花发育转变过程中短暂淀粉的积累和聚糖组成受光周期调控。我们采用多学科的方法，证明了 CO 在调节 GRANULE BOUND STARCH SYNTHASE (GBSS) 基因的表达水平和时间方面的作用。此外，我们详细描述了一个参与短暂淀粉合成的 GBSS 突变体，并分析了其开花时间表型与其改变合成直链淀粉的能力以及改变植物游离糖含量之间的关系。CO 通过光周期对淀粉动态平衡的调节可能对增加花发育转变所需的糖动员至关重要。这一发现有助于我们理解开花过程。
