Galloylated flavan-3-ols are key quality and health-related compounds in tea plants of Camellia section Thea. Camellia ptilophylla and Camellia sinensis are two representative species known for their high levels of galloylated flavan-3-ols. Building on our knowledge of galloyl catechin biosynthesis in C. sinensis, we now focus on the biosynthesis of galloylated phenolics in C. ptilophylla, aiming to elucidate the mechanisms underlying the high accumulation of these compounds in Camellia species. The phenolic compounds in C. ptilophylla were identified and quantified using chromatographic and colorimetric methods. Genes involved in polyphenol galloylation were identified by correlating gene expression with the accumulation of galloylated phenolics across 18 additional Camellia species and 1 related species using Weighted Gene Co-expression Network Analysis. Key findings include the co-expression of SCPL4/2 and SCPL5 subgroup enzymes as crucial for galloylation of catechins, while SCPL3 and SCPL8 showed enzymatic activity related to hydrolyzable tannin synthesis. Variations in the amino acid sequences of SCPL5, particularly in the catalytic triad (T-D-Y vs. S-D-H) observed in C. ptilophylla and C. sinensis, were found to significantly affect enzymatic activity and EGCG production. In conclusion, this research provides important insights into the metabolic pathways of C. ptilophylla, emphasizing the critical role of SCPL enzymes in shaping the phenolic profile within the section Thea. The findings have significant implications for the cultivation and breeding of tea plants with optimized phenolic characteristics.

中文翻译：

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伴生丝氨酸羧肽酶样酰基转移酶催化位点的失活突变可增强茶茶碱合金化


合金化黄烷-3-醇是山茶科茶树的关键品质和健康相关化合物。Camellia ptilophylla 和 Camellia sinensis 是两个代表性物种，以其高水平的合金化黄酮-3-醇而闻名。基于我们对 C. sinensis 中 galloyl 儿茶素生物合成的了解，我们现在专注于 C. ptilophylla 中galloy化酚类的生物合成，旨在阐明这些化合物在山茶物种中高度积累的机制。采用色谱法和比色法对 C. ptilophylla 中的酚类化合物进行鉴定和定量。通过使用加权基因共表达网络分析将基因表达与另外 18 种山茶花物种和 1 个相关物种的合金化酚类物质的积累相关联，鉴定参与多酚合金化的基因。主要发现包括 SCPL4/2 和 SCPL5 亚群酶的共表达对儿茶素的合金化至关重要，而 SCPL3 和 SCPL8 显示出与可水解单宁合成相关的酶活性。发现 SCPL5 氨基酸序列的变化，特别是在 C. ptilophylla 和 C. sinensis 中观察到的催化三联体 （T-D-Y vs. S-D-H） 中，显着影响酶活性和 EGCG 产生。总之，这项研究为茶叶梭菌的代谢途径提供了重要的见解，强调了 SCPL 酶在塑造 Thea 截面内酚类物质谱中的关键作用。这些发现对具有最佳酚类特性的茶树的栽培和育种具有重要意义。