文心兰OnGI在拟南芥中异源表达促进开花

The Heterologous Expression of Oncidium OnGI Promotes Flowering in Arabidopsis thaliana

对文心兰(Oncidium)进行不同的光周期处理,结果发现长日照条件有利于花芽的形成;克隆获得文心兰OnGI基因,其编码区长3483 bp,编码1161个氨基酸;多序列比对结果显示其与石斛(Dendrobium nobile)DnGI同源性最高,为86.57%;进化树分析结果表明其与其他兰科植物为同一组。组织表达分析结果显示,OnGI在文心兰花中表达量最高,尤其在花苞形成初始时期;在不同生长时期的叶片中,花芽分化期OnGI表达量达到峰值;在不同光周期条件下,OnGI的表达模式存在差异,与拟南芥(Arabidopsis thaliana)类似。亚细胞定位显示,OnGI定位在细胞核中。在拟南芥中过表达OnGI可以提早开花。根据结果推测,文心兰和拟南芥可能存在类似的光周期调控GI表达的机制,调控植株开花。

In this study,it was found that long-day condition could promote the flower bud differentiation of Oncidium under different photoperiod treatments.The OnGI gene of Oncidium was cloned,and its coding region was 3483 bp long,encoding 1161 amino acids.The results of multiple sequence alignment showed that it had the highest homology with Dendrobium nobile DnGI(86.57%).The phylogenetic tree analysis showed that it was classified into the same group with other orchids.Tissue expression analysis showed that the expression of OnGI was the highest in flowers,especially at the initial stage of bud formation,and in leaves at different growth stages,the expression of OnGI peaked at the stage of flower bud differentiation.Under different photoperiod conditions,the expression pattern of OnGI was different,similar to that of Arabidopsis thaliana.The results of subcellular localization showed that OnGI was localized in the nucleus.Overexpression of OnGI in Arabidopsis thaliana could lead to earlier flowering.Based on the above results,we speculate that there may be a similar photoperiod regulation mechanism of GI expression in Arabidopsis thaliana and to regulate plant flowering.