文心兰开花相关OnAP1-like基因的克隆及表达分析

以南茜文心兰（Gower Ramsey）盛花期花葶提取的总RNA为模板，通过RT-PCR与RACE扩增，获得一个958 bp的AP1（APETALA1）-like基因的cDNA全长序列，其基因编码区690 bp，共编码氨基酸229个，命名为OnAP1-like（登录号：KC426946）。蛋白质二级结构分析表明，该蛋白质48.91%为α螺旋，10.92%为β折叠，40.17%为无规则卷曲，为亲水性蛋白质。蛋白序列比对和进化树分析表明，OnAP1-like 蛋白与蕙兰AP1-like蛋白一致性最高，进化距离最近。利用RT-qPCR对从文心兰不同时期不同器官中的OnAP1-like基因表达量进行分析，结果表明，同一器官不同发育时期比较，在叶中，花蕾期的表达量最高；在根中，随发育时间推移，表达量逐渐升高，至花后期达到最高；在花葶中的表达量的趋势与根相同。同一时期不同器官比较，抽葶前，根中表达量高于叶片；花蕾期，花瓣中的表达量最高；盛花期和花后期，花葶中的表达量最高。推测该基因在花的发育及形成中发挥作用。

Cloning and Expression Analysis of OnAP1-like Gene from Oncidium ‘Gower Ramsey’

Afull-length 958 bp cDNA of AP1（APETALA1）-like was obtained by RT-PCR and RACE amplification the total RNA extracted from the scapes of Oncidium‘Gower Ramsey’（Orchidaceae）at flowering stage. The gene consisted of 690 bp gene encoding region which encoding a protein of 229 amino acids，was designated as OnAP1-like（accession number：KC426946）. The analysis of secondary structure of protein showed that the protein was hydrophilic，and it contained 48.91% of α-helix，10.92% of β-sheet and 40.17% of random coil. The analysis of protein sequence alignment and cluster showed that the OnAP1-like was close to AP1-like of Cymbidium faberi with an overall sequence similarity. Using RT-qPCR to analysis the expression quantity of OnAP1-like of different organsfrom Oncidium in different stages，the results showed that in different development stages，the expression level of leaves was the highest in flower budding stage，that of root and scapes gradually increased with development and obtained the highest expression level at post-flowering stage. In different organs，the expression level of roots was higher than that of leaves before reproductive growth stage；The expression level of petals was the highest in flower budding stage，and that of scapes was the highest in flowering and post-flowering stage. The results suggest that OnAP1-like gene play a significant role in the development and formation of flowers in Oncidium‘Gower Ramsey’.