摘要： 为研究赤霉素合成途径关键酶基因,了解果树的矮化机理。以苹果品种富士当年生新梢的茎尖为试材,以苹果基因组数据库为依据,克隆了编码苹果CPS的基因MdCPS(GenBanK登录号:KC433942.1)。该基因gDNA序列含有15个外显子和14个内含子,其编码序列(Coding sequence,CDS)长度为2 400 bp,共编码799个氨基酸。在已发表的金冠苹果基因组中,与该基因相对应的转录本是MDP0000147908,它的定位区间为chr11:32433834~32439214。同源性分析表明,MdCPS与其他植物的CPS间有较高的相似性(49%~67%)。以杂交组合富士(普通型)×舞姿(柱型)的亲本品种及F₁后代当年生新梢的茎尖组织为试材,实时荧光定量PCR(qRT-PCR)分析表明,尽管该基因在柱型亲本中的表达水平显著低于普通型亲本,但在其后代的柱型与普通型群体间差异并不明显。同时,在柱型杂种及其普通型突变体间的分析结果也表明,MdCPS的表达水平与柱型性状没有明显的相关性。可见,柱型苹果茎尖组织中活性赤霉素含量偏低受其合成早期步骤关键酶基因MdCPS的影响不大。

关键词: 苹果, 赤霉素, 柯巴焦磷酸合酶基因(CPS), 柱型性状

Abstract: Gibberellines are the most important phtyohormones influencing the plant height of fruit trees.Researches of the genes encoding the critical enzymes in gibberellin biosynthesis are significant to understanding the mechanism of dwarf tree architectures.This study reported the isolation of the MdCPS (GenBank accession number:KC433942.1),encoding CPS in apple, from primary apical shoots of the variety Fuji based on the apple genome database.The gDNA sequence of MdCPS contained 15 exons and 14 introns,and the coding sequence(CDS)of it was 2 400 bp,which encoded a polypeptide of 799 amino acids.The transcript MDP0000147908 that spanned chromosome 11 from location 32433834 to 32439214 in the published Golden delicious apple genome corresponds to this gene.Homology analysis indicated that the deduced MdCPS shared a higher level of similarity(49% -67%)with CPS protein from other plant species.Using the primary apical shoots of the parents and F₁ progenies of Fuji(standard)×Telamon(columnar)as plant materials,quantitative real-time PCR(qRT-PCR)analyses showed that even though the transcription level of this gene in the columnar parent was lower than that in the standard parent,there was no significant difference was observed between the two populations of columnar and standard progenies.At the same time,qRT-PCR analysis in the columnar hybrids and their correspondent standard mutants indicated that the expression level of MdCPS was not relevant to the columnar growth habit.These results suggested that the lower content of active gibberellins in columnar apple apical shoots was not distinctively influenced by MdCPS in the early stage of gibberellins synthesis.

Key words: Apple, Gibberellins, Ent-copalyl diphosphate synthase(CPS), Columnar trait

中图分类号: 

• Q78

• S661.03