茶树特异种质资源高EGCG3′′Me性状形成的分子机制解析

摘要/Abstract

摘要： 甲基化儿茶素具有显著的抗过敏等生理活性,且其稳定性和肠道吸收率高于未甲基化的儿茶素。然而天然具有高甲基化儿茶素含量的茶树种质资源相对稀缺。通过测定447份来自不同地区且遗传背景广泛的茶树种质资源中表没食子儿茶素3-O-(3-O-甲基)没食子酸酯（EGCG3′′Me）含量,发现2份高EGCG3′′Me含量的特异茶树种质资源‘金秀2-2’（JX）和‘品明茶’（PM）。以高EGCG3′′Me含量茶树资源JX、PM、‘红富贵’（BFK）,以及EGCG3′′Me含量低于检测限的茶树资源‘舒茶早’（SCZ）为研究材料,分析茶树黄酮醇和花青素O-甲基转移酶（Flavonol and anthocyanin O-methyltransferase,CsFAOMT）基因表达量,结果显示,JX、PM和BFK中的CsFAOMT1相对表达水平无显著差异,均显著高于SCZ。进一步在4份茶树资源中克隆出4种CsFAOMT1等位基因,均含有CsFAOMT1.3。酶活性分析结果显示,3份高EGCG3′′Me含量茶树资源所含的CsFAOMT1等位基因编码蛋白的活性都较高,且相互间差异较小。结果表明,JX、PM能富集EGCG3′′Me,是其CsFAOMT1表达水平高导致的。本研究通过发掘高EGCG3′′Me含量特异茶树种质,解析其特异性状形成的分子机制,为培育高甲基化儿茶素茶树新品种提供了材料和理论基础。

关键词: 茶树, 甲基化儿茶素, O-甲基转移酶, 等位基因

Abstract: Methylated catechins exhibit significant physiological activities, such as anti-allergy effects, and demonstrate stronger stability and higher oral absorption rate than unmethylated catechins. However, tea germplasms rich in methylated catechins are relatively rare. This study measured the EGCG3′′Me content in 447 tea germplasms from different regions with extensive genetic backgrounds, and two unique tea germplasms with high EGCG3′′Me content, namely ‘Jinxiu 2-2’ (JX) and ‘Pinming Tea’ (PM), were found. The tea germplasms JX, PM, and ‘Hongfugui’ (BFK) with high EGCG3′′Me content, as well as ‘Shuchazao’ (SCZ) with EGCG3′′Me content below the detection limit, were used as research materials. Relative expression levels of flavonol and anthocyanin O-methyltransferase (CsFAOMT1) in JX, PM, and BFK were significantly higher than that in SCZ. Further analysis reveals that four types of CsFAOMT1 alleles were cloned from the four tea germplasms, and all of them contain CsFAOMT1.3. Enzyme activity analysis at the protein level reveals that the CsFAOMT1 protein activities in the three tea germplasms with high EGCG3′′Me content all exhibit high activity with minimal differences between them. These results indicate that JX and PM can enrich EGCG3′′Me due to their high expression levels of CsFAOMT1. This study identified tea germplasm with high EGCG3′′Me content and elucidated the molecular mechanisms underlying its unique traits, providing important materials and theoretical basis for breeding new tea cultivars with high methylated catechin content.

Key words: tea plant, methylated catechins, O-methyltransferase, allele

中图分类号:

S571.1
S324

厉媛媛, 姚明哲, 金基强. 茶树特异种质资源高EGCG3′′Me性状形成的分子机制解析[J]. 茶叶科学, 2025, 45(6): 909-919.

LI Yuanyuan, YAO Mingzhe, JIN Jiqiang. Elucidation of the Molecular Mechanisms Underlying the Formation of the High EGCG3′′Me Content in Tea Germplasms[J]. Journal of Tea Science, 2025, 45(6): 909-919.

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