马铃薯块茎GBSS Ⅰ基因的cDNA克隆及其序列特征分析

Analysis of cloning and sequence characteristics of cDNA encoding the GBSS Ⅰ gene from tubers of Solanum tuberosum

以马铃薯普通栽培种"甘农薯2号"块茎为材料,利用RNA提取试剂盒提取总RNA,通过RT-PCR技术和DNA序列测定分析,证实获得了马铃薯颗粒结合淀粉合成酶(GBSS I)基因的cDNA序列。该cDNA全长1824bp,包括607个氨基酸和1个终止密码子序列,且与原序列(accession number X58453)同源性为99.78%,但与其他科植物GBSS基因的同源性较低,注册该基因到GenBank中,注册号为EU403426。利用生物信息学相关软件分析预测GBSS I基因cDNA序列编码的蛋白质功能和结构,结果发现,该蛋白与其他15种植物GBSS蛋白一样,具有3个完全保守区域,并具许多重要功能位点,且与农杆菌淀粉合成酶具有相似三级结构模型,表明该蛋白具淀粉合成功能。

The cDNA clone encoding GBSSⅠ was obtained by extracting total RNA from tubers of Solanum tuberosum CV.Gannongshu NO.2 using an RNA isolation system,RT-PCR（reverse transcription-polymerase chain reaction）,then measuring and analyzing the DNA sequence.The full-length of cDNA was 1 824bp,which contained 607amino acids and a termination codon：the homology was 99.78% compared with the original sequence（Accession Number X58453）,but the homologies were very low compared with other families. The gene has the registration number EU403426 in GenBank.The protein function and structure of the GBSS Ⅰ gene cDNA sequence were predicted and analyzed using related software of bioinformatics.The protein had three completely conserved domains as in other GBSS proteins of 15 plants and it had a number of important functional sites.It also had a tertiary structure similar to starch synthase of Agrobacterium,which suggests that the protein functioned in starch synthesis.