【作者】 李叶云； 芦原坦；

【Author】 LI Ye-yun1, ASHIHARA Hiroshi 2 (1.Key Laboratory of Tea Biochemistry and Biotechnology of Ministry of Education, Anhui Agricultural University, Hefei, Anhui, 230036;2.Department of Biological Sciences, Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo, 112-8610, Japan)

【机构】 安徽农业大学茶叶生物化学与生物技术教育部重点实验室； 御茶水女子大学；

【摘要】 用半定量PCR方法,分别研究了4个月幼龄茶树嫩叶、成熟叶片、茎、根以及愈伤组织中咖啡碱合成酶(TCS1)、次黄嘌呤苷-5’-单酸磷酸脱氢酶(TIDH)、s-腺苷甲硫氨合成酶(sAMS)等咖啡碱生物合成相关基因的差异表达。研究表明,茶树嫩叶中TCS1基因表达量高于其它部位,TIDH基因叶内表达量多于茎和根中,但sAMS表达量在茶树各个部位差异不大。在茶树愈伤组织中,幼嫩组织TCS1基因表达量也远高于老化组织。这些结果支持前人酶学与代谢学研究中咖啡碱主要在嫩叶中生物合成的结论,可以推测嫩叶中咖啡碱的生物合成取决于咖啡碱合成酶较强的表达。更多还原

【Abstract】 Using semi-quantitative reverse transcription-PCR, we studied the expression of genes encoding caffeine synthase (TCS1), inosine-5’-monophosphate dehydrogenase (TIDH), S-adenosyl-L-methionine synthase (sAMS), phenylalanine ammonia-lyase (PAL) and α-tubulin (Tua1) in young and mature leaves, stems and roots of 4-month-old tea seedlings and young and old tea tissue cultures. The amounts of transcripts of TCS1 were much higher in young leaves than in other parts of the plant. Expression of TIDH was greater in leaves than in other parts. Little difference in the amounts of transcripts of PAL, sAMS and Tua1 was found between various organs of tea seedlings. Larger amounts of transcripts of TCS1 and PAL were found in young callus tissues than in old tissues. These results support our conclusion that caffeine is synthesized mainly in young leaf tissues, deriving from previous enzymatic and metabolic studies. We propose that marked caffeine biosynthesis in young leaves is dependent on greater expression of the TCS1 gene in the organ.更多还原