An integrated transcriptomics and metabolomics analysis of the Cucurbita pepo nectary implicates key modules of primary metabolism involved in nectar synthesis and secretion
An integrated transcriptomics and metabolomics analysis of the Cucurbita pepo nectary implicates key modules of primary metabolism involved in nectar synthesis and secretion
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DOI：
10.1002/pld3.120
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发表时间：
2019-02-01
期刊：
影响因子：
3
通讯作者：
Carter, Clay J.
中科院分区：
文献类型：
--
作者：
Solhaug, Erik M.;Roy, Rahul;Carter, Clay J.
花蜜是花朵提供给传粉者的主要奖励，以吸引重复的访问。西葫芦（南瓜）是研究花蜜生物学的一个很好的模型，因为它有大的蜜腺，相对于大多数其他物种产生大量的花蜜。南瓜也是雌雄同株的，在同一株植物上有雌花和雄花，这允许对同一个体的蜜腺功能进行比较分析。在这里，我们报告的蜜腺转录组从女性和男性蜜腺在花成熟的四个阶段。对这些转录组的分析和随后的验证性实验揭示了蜜腺中从淀粉合成到淀粉降解和蔗糖生物合成的代谢进程。这些结果与先前发表的花蜜分泌模型是一致的，也表明了富含蔗糖的花蜜是如何在没有跨质膜主动运输的情况下合成和分泌的。花蜜的非靶向代谢组学分析也确定了40种代谢物在女性和男性花蜜，一些显示优先积累的花蜜中的男性或女性的花朵。累积起来，这项研究确定了反向遗传学方法研究蜜腺功能的基因靶点，以及以前未报道的可能在植物-生物相互作用中起作用的花蜜代谢物。
Nectar is the main reward that flowers offer to pollinators to entice repeated visitation. Cucurbita pepo (squash) is an excellent model for studying nectar biology, as it has large nectaries that produce large volumes of nectar relative to most other species. Squash is also monoecious, having both female and male flowers on the same plant, which allows comparative analyses of nectary function in one individual. Here, we report the nectary transcriptomes from both female and male nectaries at four stages of floral maturation. Analysis of these transcriptomes and subsequent confirmatory experiments revealed a metabolic progression in nectaries leading from starch synthesis to starch degradation and to sucrose biosynthesis. These results are consistent with previously published models of nectar secretion and also suggest how a sucrose-rich nectar can be synthesized and secreted in the absence of active transport across the plasma membrane. Nontargeted metabolomic analyses of nectars also confidently identified 40 metabolites in both female and male nectars, with some displaying preferential accumulation in nectar of either male or female flowers. Cumulatively, this study identified gene targets for reverse genetics approaches to study nectary function, as well as previously unreported nectar metabolites that may function in plant-biotic interactions.