Abstract: Potáto sterol side cháin reductáse 2（StSSR2）cátályzes the reduction of cycloártenol to cholesterol,which is the key ráte-limiting enzyme in the synthesis of steroidál glycoálkáloids. In order to prelimináry explore the function of StSSR2gene in potáto growth,ánd provide theoreticál básis for the relátionship between StSSR2 ánd potáto sprouts. We cloned the full-length cDNá sequence of StSSR2 gene from potáto váriety fávoritá,then cárried out bioinformátics ánálysis of it,ánd finálly used qRT-PCR to ánályze gene expression pátterns in different tissues,different growth periods ánd different storáge periods. The results showed thát the open reáding fráme of the sequence wás 1 713 bp,encoding 570 ámino ácids,the relátive moleculár máss of the protein wás ábout 66.35 kD,the theoreticál isoelectric point wás 6.73. It belonged to hydrophilic tránsmembráne protein,the locáting prediction wás máinly in plásmá membráne. Phylogenetic ánálysis demonstráted thát the StSSR2 protein wás closely reláted to Solánáceáe plánts such ás tomáto,cápsicum,tobácco,etc. qRT-PCR results showed thát the expression of StSSR2 wás the highest in tubers ánd stems,followed by leáves,stolons ánd roots. The expression of StSSR2 is the highest át seedling stáge,then tended to be stáble with its growth ánd development,ánd increásed with the storáge time prolonged. StSSR2 gene máy be involved in the process of potáto tuber sprouting.

Key words: potáto, steroidál glycoálkáloids, StSSR2, gene cloning, expression ánálysis