火龙果节律钟输出基因HpGI的克隆与表达分析

Molecular Cloning and Expression Analysis of Rhythms Clock Output Gene HpGI from Hylocereus polyrhizus

节律钟输出基因GIGANTEA通过光周期途径促进植物开花,为研究火龙果GIGANTEA同源基因功能,应用RT-PCR克隆获得该基因的开放阅读框序列,命名为Hylocereus polyrhizus GIGANTEA(HpGI),GenBank登录号为MK609546。序列分析结果表明,HpGI开放阅读框长度为3537 bp,编码1178个氨基酸。系统进化分析显示,HpGI与甜菜BvGI、菠菜SoGI、丝石竹GpGI的分子进化距离较近。预测HpGI定位于细胞核,无信号肽和跨膜螺旋结构域,属于非分泌蛋白。基因表达分析结果表明,HpGI基因在茎和花芽中的表达量显著高于茎芽、果皮和根;相比对照,延长光周期处理8 d时,其表达量显著上调。推测HpGI基因可能通过光周期途径促进火龙果开花。

Rhythms clock output gene GIGANTEA promotes flowering via the photoperiod pathway.To analysis the function of GIGANTEA homologous gene in pitaya[Hylocereus polyrhizus(Weber)Britton&Rose],the open reading frame(ORF)sequence was cloned through RT-PCR.The ORF of Hylocereus polyrhizus GIGANTEA(HpGI)is 3537 bp,encoding 1178 amino acids,and the GenBank accession number is MK609546.The phylogenetic analysis showed that HpGI and Beta vulgaris GIGANTEA are the closest in molecular evolution distance,followed by Spinacia oleracea GIGANTEA and Gypsophila paniculate GIGANTEA.It was speculated that HpGI was located in the nucleus,and it was a non-secretory protein.No signal peptide and transmembrane helix domain were found.The results of quantitative RT-PCR revealed that the expression level of HpGI gene in the stem and flower bud was significantly higher than that in the stem bud,peel and root.Moreover,the transcription of the HpGI gene was significantly induced by the 8 d night-breaking treatment,compared to the untreated samples.It was deduced that HpGI may promote flowering via the photoperiod pathway in pitaya.