BACKGROUND AND AIMS Sugar composition is a key determinant of fruit quality. Soluble sugars and starch concentrations in fruits vary greatly from one species to another. The aim of this paper was to investigate similarities and differences in sugar accumulation strategies across ten contrasting fruit species using a modeling approach. METHODS We developed a coarse-grained model of primary metabolism based on the description of the main metabolic and hydraulic processes (synthesis of other compounds than sugar and starch, synthesis and hydrolysis of starch, water dilution) involved in the accumulation of soluble sugars during fruit development. KEY RESULTS Statistical analyses based on metabolic rates separated the species into six groups according to the rate of synthesis of compounds other than sugar and starch. Herbaceous species (cucumber, tomato, eggplant, pepper and strawberry) were characterized by a higher synthesis rate than woody species (apple, nectarine, clementine, grape and kiwi). Inspection of the dynamics of the processes involved in sugar accumulation revealed that net sugar importation, metabolism and dilution processes were remarkably synchronous in most herbaceous plants, whereas in kiwifruit, apple and nectarine, processes related to starch metabolism were temporally separated from other processes. Strawberry, clementine and grape showed a distinct dynamic compared to all other species. CONCLUSIONS Overall, these results provide fresh insights into species-specific regulatory strategies and into the role of starch metabolism in the accumulation of soluble sugars in fleshy fruits. In particular, inter-specific differences in development period shape the coordination of metabolic processes and affect priorities for carbon allocation across species. The six metabolic groups identified by our analysis do not show a clear separation into climacteric and non-climacteric species, possibly suggesting that the metabolic processes related to sugar concentration are not tightly affected by ethylene-associated events.

中文翻译：

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模型辅助比较十种肉质水果的糖积累模式突出了草本和木本物种之间的差异


背景和目的 糖成分是水果品质的关键决定因素。水果中可溶性糖和淀粉的浓度因品种而异。本文的目的是使用建模方法研究十种对比水果品种糖积累策略的异同。方法我们基于对果实过程中可溶性糖积累所涉及的主要代谢和水力过程（糖和淀粉以外的其他化合物的合成、淀粉的合成和水解、水稀释）的描述，开发了初级代谢的粗粒度模型发展。主要结果 基于代谢率的统计分析根据糖和淀粉以外的化合物的合成率将物种分为六组。草本物种（黄瓜、番茄、茄子、胡椒和草莓）的特点是合成率高于木本物种（苹果、油桃、克莱门氏小柑橘、葡萄和猕猴桃）。对糖积累过程动态的检查表明，大多数草本植物的净糖输入、代谢和稀释过程非常同步，而在猕猴桃、苹果和油桃中，与淀粉代谢相关的过程暂时与其他过程分离。与所有其他物种相比，草莓、克莱门氏小柑橘和葡萄表现出独特的活力。结论总的来说，这些结果为物种特异性调控策略以及淀粉代谢在肉质水果中可溶性糖积累中的作用提供了新的见解。特别是，发育时期的种间差异决定了代谢过程的协调，并影响跨物种碳分配的优先顺序。 我们的分析确定的六个代谢组没有显示出更年期和非更年期物种的明显区分，这可能表明与糖浓度相关的代谢过程并未受到乙烯相关事件的严格影响。