柱型与普通型苹果茎尖组织中GA2ox基因的序列比较及表达量分析

Sequence and Expression Analysis of GA2ox Gene from Shoots Apical Tissue between Columnar and Standard Apple

以柱型苹果舞姿和普通型苹果富士茎尖为试材,克隆赤霉素合成代谢途径中的关键酶基因GA2ox,并对二者茎尖组织中GA2ox基因进行序列比较和表达分析。结果表明,两品种中GA2ox基因cDNA序列长度均为1 014bp,编码337个氨基酸。cDNA序列中存在2处单核苷酸差异,其中1处差异会引起编码氨基酸的改变。与已发表的苹果基因组中同源序列的比较分析表明,舞姿和富士cDNA序列上的差异不是造成柱型性状的原因。同时,利用实时荧光定量PCR方法,对两品种及其杂交F1代杂种的检测表明,柱型苹果茎尖中GA2ox基因的表达量明显低于普通型苹果。

The cDNA sequences of GA2ox gene coding the critical enzyme GA 2-oxidase（GA2ox ） in the pathway of gibberellins biosynthesis were isolated from apple stem apical tissue of the columnar cultivar Telamon and the standard cultivar Fuji, respectively. Both of them was 1 014 bp in size and encoded a polypeptide with 337 amino acids. Sequence analysis showed that there were two single nu- cleotide differences in cDNA, and one of them could result in amino acid change. Further analysis with the homological sequence searching from the published apple physical genome of Golden Delicious demonstrated that the cDNA differences between Telamon and Fuji were not the cause for columnar phenotype. Meanwhile, the real-time quantitative PCR analysis in the two cnltivars and their F1 prog- enies indicated that GA2ox gene was expressed in a lower level in shoot apex of columnar apple than it in standard apple.