Pear is one of the most important fruit crops worldwide. Anthocyanins and procyanidins (PAs) are important secondary metabolites that affect the appearance and nutritive quality of pear. However, few studies have focused on the molecular mechanism underlying anthocyanin and PA accumulation in pear. We conducted metabolome and transcriptome analyses to identify candidate genes involved in anthocyanin and PA accumulation in young fruits of the pear cultivar ‘Clapp Favorite’ (CF) and its red mutation cultivar ‘Red Clapp Favorite’ (RCF). Gene–metabolite correlation analyses revealed a ‘core set’ of 20 genes that were strongly correlated with 10 anthocyanin and seven PA metabolites. Of these, PcGSTF12 was confirmed to be involved in anthocyanin and PA accumulation by complementation of the tt19–7 Arabidopsis mutant. Interestingly, PcGSTF12 was found to be responsible for the accumulation of procyanidin A3, but not petunidin 3, 5-diglucoside, opposite to the function of AtGSTs in Arabidopsis. Transformation with PcGSTF12 greatly promoted or repressed genes involved in anthocyanin and PA biosynthesis, regulation, and transport. Electrophoretic mobility shift and luciferase reporter assays confirmed positive regulation of PcGSTF12 by PcMYB114. These findings identify a core set of genes for anthocyanin and PA accumulation in pear. Of these, PcGSTF12, was confirmed to be involved in anthocyanin and PA accumulation. Our results also identified an important anthocyanin and PA regulation node comprising two core genes, PcGSTF12 and PcMYB114. These results provide novel insights into anthocyanin and PA accumulation in pear and represent a valuable data set to guide future functional studies and pear breeding.

中文翻译：

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转录组和代谢组学分析提供了梨中花色苷和原花青素积累的见解

梨是世界上最重要的水果作物之一。花青素和原花青素（PAs）是重要的次生代谢产物，会影响梨的外观和营养品质。但是，很少有研究关注梨中花色苷和PA积累的分子机制。我们进行了代谢组和转录组分析，以鉴定参与梨品种'Clapp Favorite'（CF）和其红色突变品种'Red Clapp Favorite'（RCF）的年轻果实中花色苷和PA积累的候选基因。基因-代谢物相关性分析揭示了一个“核心集”，其中有20个基因与10个花色苷和7个PA代谢产物高度相关。其中，通过补充tt19-7拟南芥突变体，证实PcGSTF12与花色苷和PA积累有关。有趣的是 发现PcGSTF12负责原花青素A3的积累，而不是负责矮牵牛苷3，5-二糖苷的积累，这与拟南芥中AtGST的功能相反。用PcGSTF12进行的转化极大地促进或抑制了花色苷和PA生物合成，调控和转运所涉及的基因。电泳迁移率变化和荧光素酶报告基因分析证实了PcMYB114对PcGSTF12的正调控。这些发现确定了梨中花色苷和PA积累的核心基因集。其中，PcGSTF12被证实与花色苷和PA的积累有关。我们的研究结果还确定了一个重要的花色苷和PA调控节点，其中包含两个核心基因PcGSTF12和PcMYB114。