紫色马铃薯类黄酮3，′5′-羟化酶基因（StF3′5′H）的克隆及分析

类黄酮3′，5′羟-化酶（ flavonoid 3′，5′-hydroxylase， F3′5′H）是植物花青素生物合成途径中的一个关键酶，紫色土豆（ Solanum tueb or sum） F3′5′H基因的克隆将为花青素合成调控和花青素代谢工程研究提供优质基因资源。研究采用RACE技术克隆了紫色土豆F3′5′H基因的cDNA全长序列，用生物信息学方法对其核苷酸和蛋白质序列进行了分析，并用半定量PCR 技术分析了F3′5′H基因在不同组织中的表达情况，同时研究了赤霉素和蔗糖处理后F3′5′H基因表达与花青素积累之间的相关性。研究结果表明，克隆的紫色土豆F3′5′H的cDNA全长为1854 bp，包含一个1530 bp的完整ORF，共编码509个氨基酸。生物信息学分析表明，StF3′5′H基因推测编码的氨基酸序列与其它植物的F3′5′H蛋白的相似性很高。 StF3′5′H基因的表达具有组织特异性，在紫色土豆根、茎和叶柄中都有表达，其中在叶柄中表达最强，而在块茎、叶轴和叶片中几乎检测不到StF3′5′H基因的表达。赤霉素和蔗糖能促进紫色土豆StF3′5′H基因的表达，进而促进花青素的积累。

Cloning and expression analysis of a flavonoid 3′, 5′-hydroxylase（F 3′5′H） gene rfo m purple po tato （So lanum tuberosum）

Flavonoid 3′, 5′-hydroxylase （ F3 ′5′H） was a key enzyme involved in plant anthocyanin biosynthesis pathway.The cloning and expression analysis of F3′5′H gene from purple potato would provide the high quality genetic resources for further researches on the anthocyanin biosynthesis regulation and metabolic engineering.The full-length cDNA sequence of F3′5′H was cloned from Solanum tu-berosum using RACE techniques, and bioinformatic method was used to study cDNA sequence and deductive amino acid sequence. Semi-quantitative PCR method was used to analyze the expression of the F3′5′H gene in different organs.The relationship between the anthocyanin accumulation and the expression of the F3′5′H gene after processed by GA3 and sucrose were also analyzed.The results re-vealed that the full-ength cDNA sequence of StF 3′5′H consisted of 1 854 bp with an intact open reading frame of 1530 bp, encoding a polypeptide of 509 amino acids.Homology analysis indicated that the putative F3′5′H amino acid was highly homologous to other F3′5′H proteins from different species. StF3′5′H was expressed at different levels in different organs, which was found to be expressed in roots, stems and leafstalks ,but not in tubers, rachises or leaves .The highest expression level was detected in leafstalks.The anthocy-anin accumulation was induced by GA3 and sucrose, as well as the expression of StF 3′5′H.