Carbohydrate Metabolism and Signaling in Squash Nectaries and Nectar Throughout Floral Maturation
Carbohydrate Metabolism and Signaling in Squash Nectaries and Nectar Throughout Floral Maturation
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DOI：
10.1104/pp.19.00470
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发表时间：
2019-08-01
期刊：
影响因子：
7.4
通讯作者：
Carter, Clay J.
中科院分区：
文献类型：
--
作者：
Solhaug, Erik M.;Johnson, Elizabeth;Carter, Clay J.
花蜜是植物为了吸引传粉者而产生的含糖溶液。花蜜分泌的一般机制已建立从拟南芥（拟南芥）的遗传研究，然而，支持这种模式的代谢和生化证据是稀缺的其他植物物种。我们使用南瓜（西葫芦），以测试是否在拟南芥花蜜分泌的遗传模型是支持在其他物种的代谢水平。因此，我们分析了在整个花成熟和相关的淀粉和可溶性糖，以及花蜜量和糖在不同的生长条件下，在南瓜蜜腺碳水化合物代谢的关键酶的表达和活性。在这里，我们表明，在拟南芥花蜜分泌的重要步骤，包括蜜腺淀粉降解，Suc的合成，和Suc的出口，支持的代谢和生化数据在C。pepo。此外，我们的研究结果表明，在花蜜分泌过程中从韧皮部输入的糖，没有事先储存为淀粉，对产生C。胡椒花蜜。最后，我们预测海藻糖和海藻糖6-P在蜜腺淀粉降解和花蜜分泌中起着重要的调节作用。这些数据提高了我们对花蜜是如何在农艺学相关物种中产生的理解，并有可能用作模型，帮助我们深入了解开花植物花蜜分泌的生物化学和代谢。
Floral nectar is a sugary solution produced by plants to entice pollinator visitation. A general mechanism for nectar secretion has been established from genetic studies in Arabidopsis (Arabidopsis thaliana); however, supporting metabolic and biochemical evidence for this model is scarce in other plant species. We used squash (Cucurbita pepo) to test whether the genetic model of nectar secretion in Arabidopsis is supported at the metabolic level in other species. As such, we analyzed the expression and activity of key enzymes involved in carbohydrate metabolism in squash nectaries throughout floral maturation and the associated starch and soluble sugars, as well as nectar volume and sugar under different growth conditions. Here we show that the steps that are important for nectar secretion in Arabidopsis, including nectary starch degradation, Suc synthesis, and Suc export, are supported by metabolic and biochemical data in C. pepo. Additionally, our findings suggest that sugars imported from the phloem during nectar secretion, without prior storage as starch, are important for generating C. pepo nectar. Finally, we predict that trehalose and trehalose 6-P play important regulatory roles in nectary starch degradation and nectar secretion. These data improve our understanding of how nectar is produced in an agronomically relevant species with the potential for use as a model to help us gain insight into the biochemistry and metabolism of nectar secretion in flowering plants.