柚苦味形成相关基因CmLGT的克隆与分析

Molecular cloning and analysis of a novel gene encoding limonoid glucosyltransferase (LGT) in Citrus maxima

为研究柚苦味形成的分子机理,以梁平柚为材料,采用PCR和RT-PCR技术扩增获得了柠檬苦素类化合物葡萄糖转移酶(LGT)基因CmLGT的DNA序列和cDNA序列。cDNA长1536bp,推测的编码蛋白CmLGT包含511个氨基酸,理论分子量为57.5ku,具有1个含有44个氨基酸残基的UDP-葡萄糖结合域(UDP-glucose Binding Domain),2个含有4个氨基酸残基的保守糖基化位点。扩增得到的CmLGT基因DNA和cDNA存在26个碱基的差异,可能是DNA和cDNA分别进行扩增时,其模板为同一位点上的等位基因造成的。

Limonoid glucosyhransferase is a key enzyme in relation to the accumulation of non-bitter limonoid glucosides in citrus. In our work, limonoid glueosyltransferase （LGT） gene CraLGT was isolated and characterized from Citrus maxima ev. Liangping You. Both DNA and eDNA fragments of the gene were isolated by PCR and RT-PCR. The accessed eDNA was 1 536 bp in length encoding 511 deduced amino acids with a predicted molecular mass of 57.5 ku, which included the region for the UDP-glueose binding domain with 44 amino acid residues. There were 26 different bases between DNA and eDNA of amplified CraLGT. The reason may be that template was the allele on the single loci, while the DNA and eDNA had been amplified respectively.