The component of caffeine and theobromine of five tea plants was determined by high performance liquid chromatography.The results showed that the theobromine content was low,but caffeine content was high in the same tea plant.The theobromine was accumulated in the tea resource of low caffeine content.The expression level of sAMS and TIDH were nearly affected by the change of caffeine content,according to the differences of expression level of S-adenosylmethionine Synthetase gene(sAMS),Inosine 5'-monophosphate Dehydroge-nase (TIDH) and Caffeine Synthase gene (TCSI) analyzed by RT-PCR in different tea species and the date of caffeine content.TCSI could be expressed whatever in the high caffeine content material or in the low one,but its expression level was higher in the high caffeine content material.The reason could be that the Caffeine Synthase of vitality was low in the low caffeine content tea plant,or other regulation mechanisms could lead to the blockage of biosynthesis of caffeine and the accumulation of theobromine.%利用高效液相色谱对5份茶树资源中的咖啡碱、可可碱组分进行测定,发现咖啡碱含量高的茶树资源可可碱含量低,而咖啡碱含量低茶树资源的可可碱被积累.利用RT-PCR分析了S-腺苷甲硫氨酸合成酶基因(sAMS)、次黄嘌呤苷-5-单酸脱氢酶基因(TIDH)、咖啡碱合成酶基因(TCSI)在咖啡碱含量不同的茶树品种间的表达水平差异,并结合咖啡碱含量数据发现,sAMS和TIDH的表达水平对咖啡碱含量变化影响不明显.TCSI在高咖啡碱和低咖啡碱材料中均有表达,且TCSI在高咖啡碱材料中的表达比在低咖啡碱材料中高.推测可能是低咖啡碱茶树资源中咖啡碱合成酶活性低或者存在其他的调控机制,导致咖啡碱的生物合成受阻,使得可可碱被积累.
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