Fruit setting rewires central metabolism via gibberellin cascades
Fruit setting rewires central metabolism via gibberellin cascades
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DOI：
10.1073/pnas.2011859117
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发表时间：
2020-09-22
影响因子：
11.1
通讯作者：
Ariizumi, Tohru
中科院分区：
文献类型：
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作者：
Shinozaki, Yoshihito;Beauvoit, Bertrand P.;Ariizumi, Tohru
坐果是子房在授粉和受精后发育成果实的过程。这一过程是由番茄中的植物激素赤霉素（GA）诱导的，由组成型赤霉素响应突变体procera确定。然而，GA在坐果子房代谢行为中的作用仍然未知。本研究利用整合转录组、蛋白质组、代谢组和酶活性数据的网络分析，探讨了坐果的生化机制。我们的研究结果表明，坐果涉及到中心碳代谢的激活，增加了己糖、己糖磷酸盐和下游代谢物，包括糖酵解的中间体和衍生物、三羧酸循环以及相关的有机和氨基酸。网络分析还发现了协调代谢激活的转录中心基因SIHB15A。此外，蔗糖代谢的动力学模型预测，在未授粉的子房中，蔗糖循环具有较高的活性水平，而当糖在坐果子房的液泡中通过糖载体快速积累时，蔗糖循环被关闭，并以时间依赖性的方式通过糖载体进行积累。此外，果实凝固至少部分需要果糖激酶的活性，这可能会将果糖从液泡中提取出来，这可能会为下游途径提供养分。总的来说，我们的研究结果表明，GA级联通过在转录和转录后水平上调中心代谢酶的能力来增强汇容量。这导致蔗糖的吸收和碳通量的增加，以产生生物量和能量的成分，这是在坐果开始时子房快速生长所必需的。
Fruit set is the process whereby ovaries develop into fruits after pollination and fertilization. The process is induced by the phytohormone gibberellin (GA) in tomatoes, as determined by the constitutive GA response mutant procera. However, the role of GA on the metabolic behavior in fruit-setting ovaries remains largely unknown. This study explored the biochemical mechanisms of fruit set using a network analysis of integrated transcriptome, proteome, metabolome, and enzyme activity data. Our results revealed that fruit set involves the activation of central carbon metabolism, with increased hexoses, hexose phosphates, and downstream metabolites, including intermediates and derivatives of glycolysis, the tricarboxylic acid cycle, and associated organic and amino acids. The network analysis also identified the transcriptional hub gene SIHB15A, that coordinated metabolic activation. Furthermore, a kinetic model of sucrose metabolism predicted that the sucrose cycle had high activity levels in unpollinated ovaries, whereas it was shut down when sugars rapidly accumulated in vacuoles in fruit-setting ovaries, in a timedependent manner via tonoplastic sugar carriers. Moreover, fruit set at least partly required the activity of fructokinase, which may pull fructose out of the vacuole, and this could feed the downstream pathways. Collectively, our results indicate that GA cascades enhance sink capacities, by up-regulating central metabolic enzyme capacities at both transcriptional and posttranscriptional levels. This leads to increased sucrose uptake and carbon fluxes for the production of the constituents of biomass and energy that are essential for rapid ovary growth during the initiation of fruit set.