马铃薯GBSS基因的克隆与DNA顺序分析

MOLECULAR CLONING AND SEQUENCE OF POTATO GRANULE- BOUND STARCH SYNTHASE GENE

构建了中国马铃薯 (Solanum tuberosum)栽培品种“东农 30 3”基因文库 ,用 PCR扩增得到淀粉粒结合淀粉合成酶基因 (GBSS,granule- bound starch synthase)的部分顺序 (GB3) ,以此为探针从基因文库中筛选到 2 0个阳性克隆。测定其中 1个克隆 (GBSS1 7- 1 )的 DNA顺序共 542 8bp;它包括 GBSS基因 5′侧翼区 1 82 3 bp、结构基因 2 964 bp和 3′侧翼区 641 bp。该顺序与已报道的 GBSS顺序同源性很高 ,但 5′侧翼区最上游 730 bp尚未见文献报道 ;并存在较多的茎环结构。

It is known that tuber specific expressions of many genes exist in the process of tuber development from stolon in potato (Solanum tuberosum). Study on the regulation of those gene expression will share light on the mechanism of organ specific gene expression. Potato GBSS (granule bound starch synthase) gene, which is solely responsive for the presence of amylose in potato tuber, expression is tuber specific. The paper describes the construction of a genomic library of a Chinese potato cultivar “Dongnong 303” in which 20 clones were isolated using partial GBSS gene sequence ampified by PCR. 5428 bp DNA sequence of one clone (GBSS17 1 ) was determined, including 1823 bp 5′ flanking region, 2964 bp structure gene, and 641 bp 3′ flanking region. It is highly homologious with reported GBSS gene sequence. In addition, the 730 bp most upstream sequence of 5′ flanking region which was not reported previously contained stem and loop structures. The present result may provide some important information for further study in the molecular mechanism of organ specific gene expression.