The tea plant (Camellia sinensis L.) is an important commercial crop. Theanine and catechins, abundant in the tea plant and represented as secondary metabolites of the tea plant, contribute to the refreshing and astringent taste of tea, respectively. In this study, three C. sinensis cultivars, ‘Baojing Huangjincha 1′ (HJC1), ‘Huangjincha 2′ (HJC2), and ‘Huangjincha 168′ (HJC168) harvested in spring and summer were used to investigate differences in theanine and catechin concentrations by high-performance liquid chromatography. The expression levels of genes associated with theanine and catechin biosynthesis were investigated using a real-time quantitative polymerase chain reaction. Results indicated that theanine, aspartic acid, serine, glutamate and alanine contents were higher in spring in three cultivars, while CsGDH1 showed higher expression in summer. As for catechins, HJC1 and HJC2 accumulated more epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) contents in summer. On the contrary, HJC168 showed higher EGCG and ECG contents in spring. CsF3H showed higher expression in spring than in summer in three cultivars. Correlation analysis indicated a positive correlation between the CsGABA-T expression and theanine contents in spring and summer (p<0.05), with the activity of GABA-T in theanine synthesis, implying that CsGABA-T might be a crucial positive regulator in theanine accumulation. Besides, most catechin compounds were positively correlated with related genes expression during summer. It was presumed that catechin synthesis contributes to catechin accumulation in summer. In summary, this study provides insights into the potential regulatory mechanisms of theanine and catechins in spring and summer.

茶树（Camellia sinensis L.）是一种重要的经济作物。茶氨酸和儿茶素在茶树中含量丰富，是茶树的次生代谢产物，分别有助于茶的清爽和涩味。在本研究中, 三个中华薏苡仁品种, '宝晶黄金茶 1 ' (HJC1), '黄金茶 2 ' (HJC2), 和'黄金茶 168'（HJC168）在春季和夏季收获被用来研究在茶氨酸和儿茶素浓度通过高效液相色谱法的差异。使用实时定量聚合酶链式反应用茶氨酸和儿茶素生物合成相关的基因的表达水平进行了研究。结果表明，茶氨酸，天冬氨酸，丝氨酸，谷氨酸和丙氨酸含量春季3个品种的含量较高，而CsGDH1显示在夏季较高表达。儿茶素方面，HJC1和HJC2在夏季积累了更多的表没食子儿茶素没食子酸酯（EGCG）和表儿茶素没食子酸酯（ECG）含量。相反，HJC168在春季表现出较高的EGCG和ECG含量。CsF3H三个品种春季表达量高于夏季。相关性分析表明，春夏季CsGABA-T表达与茶氨酸含量呈正相关（p <0.05），与GABA-T在茶氨酸合成中的活性呈正相关，提示CsGABA-T可能是茶氨酸积累的重要正向调节因子。 。此外，大多数儿茶素化合物在夏季与相关基因表达呈正相关。据推测，儿茶素的合成有助于夏季儿茶素的积累。总之，本研究提供了对春夏季茶氨酸和儿茶素潜在调控机制的见解。