木薯是热带典型的高淀粉、抗逆、抗旱作物。可溶性淀粉合成酶(SSS)是植物淀粉合成过程中的关键酶之一。根据已发表的拟南芥SSSⅣ基因序列。通过同源比对从木薯AM560、KU50基因组中获得木薯MeSSSⅣ基因的cDNA序列以及该基因部分启动子序列,设计特异引物,从木薯栽培种KU50基因组DNA中克隆了MeSSSⅣ基因系列1068bp(该序列包含978bD的启动子调控序列及90bp的基因编码序列)。序列分析表明,启动子调控序中除含有典型的真核生物核心启动子区域外,还含有多个TATA—box、CAAT—box等启动子元件以及多种与脱水、激素和光响应相关的顺式作用元件,特别是发现CGACGOSAMY3、DOFCOREZM、SREATMSD、SURE等与糖信号相关的重要顺式元件,这些元件预示肌SSSⅣ基因的表达可能与糖信号相关。以上结果说明,MeSSSⅣ可能参与木薯多种代谢过程,其表达可能受多种调控因子的调节。
Cassava is a high-starch, stress resistance, drought-resistant tropical typical crops. Soluble starch synthase (SSS) is one of the key enzyme in plant starch synthesis process. According to the published SSS Ⅳ gene sequences from arabidopsis thaliana, the cassava's SSS gene sequences were acquired from AM560 and KU50 genomic DNA sequence database by nucleotide blast and Protein blast. Template specific primers were designed according to the published cassava MeSSS Ⅳ cDNA sequence as well as part of the promoter sequence, then cloned about 1 068 bp promoter sequence of MeSSSⅣ from cassava cuhivar KU50 genomic DNA, the sequence contained 978 bp promoter regulatory sequence and 90 bp coding sequence. Sequence analysis showed that the promoter regulatory sequence contains typical eukaryotic core promoter region, in addition to comprising a plurality of TATA-box, CAAT-box, etc. promoter elements and a variety of dehydration, hormone and light response cis-acting elements, especially important sugar signal cis-elements, such as CGACGOSAMY3, DOFCOREZM, SREATMSD, SURE and so on. These components indicates MeSSSⅣ expression may have positively relation to the sugar signals. The above results indicate cassava MeSSSIV may be involved in variety of metabolic processes, and its expression may be regulated by a variety of regulatory factors.