木薯氰化物合成限速酶CYP79D2基因克隆与序列分析

Cloning and Alignment of the CYP79D2 Gene Encoding the Committed Enzyme in the Synthesis of Cyanogenic Glucoside in Cassava(Manihot esculenta Crantz)

亚麻苦苷和百脉根甙等氰化物是木薯块茎、茎叶等组织或器官中的剧毒物质,细胞色素p450是调控氰化物生物合成的关键酶基因,克隆有关酶基因对于理解木薯氰化物代谢和通过转基因对木薯氰化物的改良具有重要意义。根据国际数据库中的木薯氰化物合成限速酶基因序列信息,设计特异引物,通过同源克隆法,从木薯中克隆出1626bp cDNA基因序列。序列分析表明,克隆基因共编码541个氨基酸,与数据库中的木薯CYP79D2基因在核苷酸序列、氨基酸序列同源性上均达到99%,并含有相应基因家族的保守区域,确定克隆到木薯CYP79D2全长基因。

Cassava was the main crop rich in starch,but with high content of the toxic cyanogenic glucosides linamarin and lotaustralin in all tissues,and cytochrome P450 gene catalyzing the biosynthesis of cyanogenic glucoside.In this study,the complete coding sequence（CDS） of N-hydroxylating cytochrome P450（CYP79D2） gene,which catalyzing the committed enzyme in the first step in the biosynthesis of cyanogenic glucoside,was cloned by RT-PCR from cassava（Manihot esculenta Crantz）.Analysis showed the cloned gene coding 541 deduced amino acids,and shared 99% homology both in nucleotide acid sequence and in amino acid sequence compared with other CYP79D2 isolated from cassava,and the gene include conserve domain in accordance with other members of the CYP79D2 gene family.