‘茗科1号’茶鲜叶转录和代谢轮廓的模式识别研究

Pattern Recognition of Transcriptomic and Metabolic Profiles in Tea Shoots of ‘Mingke 1’

摘要:

为挖掘乌龙茶品种鲜叶的特征特性，以绿茶品种‘福鼎大毫茶’一芽二叶或三叶为对照(CK)，分析比较了高香优质乌龙茶品种‘茗科1号’一芽二叶或三叶(TM)与中小开面二至四叶(MM)在转录和代谢水平的组成差异。结果表明, 茶树品种特性和采摘标准为影响茶鲜叶转录和代谢轮廓的重要因素，其中CK、TM和MM的转录与代谢轮廓相互间均有良好的模式区分。差异表达基因与差异代谢物的富集和关联分析结果表明，TM vs CK与MM vs TM的差异表达基因在分子功能、细胞组分和生物过程方面存在不同的GO功能富集模式，且前者拥有较多的生物过程和较少的细胞组分；“植物次生代谢产物的生物合成”、“精氨酸和脯氨酸代谢”与“类胡萝卜素生物合成”、“苯丙素的生物合成”、“甘氨酸、丝氨酸和苏氨酸代谢”分别是TM vs CK、MM vs TM在2种组学分析中的前20条共有KEGG富集代谢通路。TM vs CK中l-苯丙氨酸、反式肉桂酸和4-胍基丁酸丰度的显著降低，以及MM vs TM中胆碱丰度的显著提高和l-苯丙氨酸、l-色氨酸、l-高丝氨酸丰度的显著降低均与相应共富集代谢通路中多个基因的显著上调或下调表达密切相关。此外，MM vs TM中脱落酸丰度的显著提高与“类胡萝卜素生物合成”通路中紫黄质脱环氧化酶和番茄红素β-环化酶基因的显著上调表达高度相关。这可为阐明‘茗科1号’茶鲜叶生物学特征及其多茶类兼制特性提供参考依据。

Abstract:

To delve deeper into the unique attributes of fresh leaves from oolong tea varieties, the green tea cultivar ‘Fudingdahao’ with one bud and two or three leaves was used as the control (CK), the compositional differences at both the transcriptional and metabolic levels between two or three leaves with a bud (TM) and two to four leaves with a banjhi bud (MM) from the highly fragrant oolong tea variety ‘Mingke 1’ were analyzed. The results showed that both tea variety and harvesting standards significantly influenced the transcriptomic and metabolic profiles of tea shoots. Notably, the transcriptional and metabolic profiles of CK, TM, and MM exhibited distinct and well-defined pattern differentiations. Enrichment and correlation analysis of differentially expressed genes and metabolites revealed that TM vs CK and MM vs TM displayed distinct GO functional enrichment patterns significant in molecular functions, cellular components, and biological processes. The former had more entries in biological processes and fewer entries in cellular components. Additionally, “Biosynthesis of various plant secondary metabolites”, “Arginine and proline metabolism”, along with “Carotenoid biosynthesis”, “Phenylpropanoid biosynthesis” and “Glycine, serine, and threonine metabolism” were identified as the top 20 shared KEGG-enriched metabolic pathways in the two omics analyses of TM vs CK and MM vs TM. In TM vs CK, there was a significant decrease in the abundance of l-phenylalanine, trans-cinnamic acid, and 4-guani-dinobutyric acid, while in MM vs TM, there was a significant increase in choline abundance and a significant decrease in the abundance of l-phenylalanine, l-tryptophan, and l-homoserine. All of these changes were closely associated with significant upregulation or downregulation of multiple genes in the respective enriched metabolic pathways. Additionally, the significant increase in abscisate abundance in MM vs TM was highly correlated with significant upregulation of violaxanthin de-epoxidase and lycopene β-cyclase genes in the carotenoid biosynthesis pathway. So, these would provide the necessary reference for further elucidating the biological characteristics of fresh leaves obtained from ‘Mingke 1’ and their versatility in producing multiple types of tea.