The grafting has been commonly used in viticulture, which joints the scion from a cultivar with the stem of a rootstock from grapevine wild relatives. Grafting has crucial impacts on various phenotypes of the cultivar including phenology, biotic and abiotic resistance, berry metabolome and coloring, however, the genetics and regulation mechanisms are largely unexplored. In this study, we investigated the phenotypic, metabolomic and transcriptomic profiles at three stages (45, 75 and 105 days after flowering) of the Crimson Seedless (Vitis vinifera, CS) cultivar grafted to four rootstocks (three heterografting: CS/101–14, CS/SO4, CS/110R and one self-grafting CS/CS) with an own-rooted grafting-free Crimson Seedless (CS) used as the control. All the heterografting had a significant effect on berry reddening as early as ~45 days after flowering. The grafting of rootstocks promoted anthocyanin biosynthesis and accumulation in grape berries. The metabolomic features showed that Cyanidin 3-O-glucoside, Delphinidin 3-O-glucosid, Malvidin 3-O-glucoside, Peonidin 3-O-glucoside and Petunidin 3-O-glucoside were the pigments responsible for the purplish-red color peels. Transcriptomic analyses revealed that anthocyanins biosynthetic related genes from the upstream (phenylalanine ammonia-lyase) to the downstream (anthocyanidin 3-O-glucosyltransferase and anthocyanidin synthase) were upregulated with the accumulations of anthocyanins in heterografted plants: CS/101–14, CS/SO4 and CS/110R. At the same time, all these genes were also highly expressed and more anthocyanin was accumulated in self-grafted CS/CS samples compared to own-rooted grafting-free CS samples, suggesting that self-grafting might also have promoted berry reddening in grapevine. Our results provide global transcriptomic and metabolomic features in the regulation of berry coloring under different grafting conditions for improving the berry quality in viticulture.

中文翻译：

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代谢组学和转录组学分析揭示了自嫁和异嫁对葡萄花青素生物合成的影响

嫁接通常用于葡萄栽培，将栽培品种的接穗与葡萄野生近缘种的砧木茎连接起来。嫁接对品种的各种表型具有至关重要的影响，包括物候、生物和非生物抗性、浆果代谢组和着色，然而，遗传和调控机制在很大程度上尚未探索。在这项研究中，我们研究了嫁接到四种砧木（三种异种嫁接：CS/101-14 、CS/SO4、CS/110R 和一个自嫁 CS/CS)，其中一个自生根嫁接的 Crimson Seedless (CS) 用作对照。早在开花后~45天，所有异种嫁接对浆果变红都有显着影响。砧木的嫁接促进了葡萄果实中花青素的生物合成和积累。代谢组学特征表明，花青素 3-O-葡萄糖苷、飞燕草素 3-O-葡萄糖苷、锦葵素 3-O-葡萄糖苷、牡丹素 3-O-葡萄糖苷和矮牵牛素 3-O-葡萄糖苷是导致紫红色果皮的色素. 转录组学分析表明，从上游（苯丙氨酸解氨酶）到下游（花青素 3-O-葡糖基转移酶和花青素合酶）的花青素生物合成相关基因随着花青素在异移植植物中的积累而上调：CS/101-14, CS/ SO4 和 CS/110R。同时，与无自生根嫁接的CS样品相比，所有这些基因也高度表达并且在自嫁CS / CS样品中积累了更多的花青素，表明自嫁也可能促进葡萄藤中的浆果变红。我们的研究结果提供了在不同嫁接条件下调节浆果着色的全局转录组学和代谢组学特征，以提高葡萄栽培中的浆果质量。