Abstract

Accumulation of secondary metabolites in the young shoots of tea plants is developmentally modulated, especially flavonoids. Here, we investigate the developmental regulation mechanism of secondary metabolism in the developing leaves of tea plants using an integrated multi-omic approach. For the pair of Leaf2/Bud, the correlation coefficient of the fold change of mRNA and RPFs abundances involved in flavonoid biosynthesis was 0.9359, being higher than that of RPFs and protein (R2=0.6941). These correlations were higher than the corresponding correlation coefficients for secondary metabolisms and genome-wide scale. Metabolomic analysis demonstrates that the developmental modulations of the structural genes for flavonoid biosynthesis-related pathways align with the concentration changes of catechin and flavonol glycoside groups. Relatively high translational efficiency (TE>2) was observed in the 4 flavonoid structural genes (chalcone isomerase, dihydroflavonol 4-reductase, anthocyanidin synthase and flavonol synthase). In addition, we originally provided the information of identified small open reading frames (small ORFs) and main ORFs in tea leaves, and elaborated the presence of upstream ORFs may have repressive effect on the translation of downstream ORFs. Our data suggest that transcriptional regulation coordinates with translational regulation and may contribute to the elevation of translational efficiencies for the structural genes involved in the flavonoid biosynthesis pathways during tea leaf development.

茶树幼芽次生代谢产物的积累受到发育调控，尤其是黄酮类化合物。本文采用综合多组学方法研究了茶树叶片次生代谢的发育调控机制。对于叶2/芽，参与类黄酮生物合成的mRNA和RPFs丰度的倍数变化的相关系数为0.9359，高于RPFs和蛋白质的相关系数（R2=0.6941）。这些相关性高于次级代谢和全基因组范围内的相关系数。代谢组学分析表明，类黄酮生物合成相关途径结构基因的发育调控与儿茶素和黄酮苷基的浓度变化一致。4个黄酮类结构基因（查尔酮异构酶、二氢黄酮醇4-还原酶、花青素合成酶和黄酮醇合成酶）的翻译效率较高（TE>2）。此外，我们率先提供了茶叶中识别出的小开放阅读框（小阅读框）和主要阅读框的信息，并阐述了上游阅读框的存在可能对下游阅读框的翻译产生抑制作用。我们的数据表明，在茶叶发育过程中，转录调控与翻译调控相协调，可能有助于提高黄酮类生物合成途径中结构基因的翻译效率。（百度翻译，仅供参考）