摘 要 ：植物MADS-box基因家族编码高度保守的转录因子，参与了包括花器官发育和开花在内的多种发育进程。为阐释兰科植物成花的分子调控机制，根据MADS-box基因保守序列设计简并引物，用RACE方法从朵丽蝶兰花葶中克隆到1个MADS-box家族基因，该基因cDNA全长960 bp，包含37 bp 5′UTR，一个738 bp的开放阅读框(ORF)和185 bp 3′UTR，共编码245个氨基酸。序列和系统进化树分析表明，该基因与其他植物的MADS-box基因具有很高的同源性，属于AP1/FUL-like亚家族，命名为DtpsMADS1，GeneBank登录号为JQ065097。实时荧光定量PCR检测结果显示：DtpsMADS1具有明显的组织表达特异性；在根和叶中，DtpsMADS1在花前期和花后期表达量较高；苗期和盛花期表达量较低；DtpsMADS1在花葶中的表达趋势与根和叶相似；而在花器官中，DtpsMADS1只有痕量表达。由此推断，DtpsMADS1可能参与开花进程调控，而不参与花器官的形态建成。
Abstract:Plant MADS-box genes encode a family of highly conserved transcription factors which involved in many different developmental processes, including floral formation and flowering. To elucidate the molecular mechanisms of floral development in the monocotyledonous species Doritaenopsis hybrid, we isolated cDNA of a MADS-box gene from this plant by the method of 3′ and 5′ rapid amplification of cDNA ends using degenerate primers designed according to the MADS-box protein family conserved region from inflorescence rachis at flowering stage. The full length cDNA of this gene is 960 bp, with a 37 bp 5′ UTR, an ORF of 753 bp and 185 bp 3′ UTR encoding 245 putative amino acids. Sequence and phylogenetic analysis indicated a high degree of predicted protein sequence identity with those from other species. The gene belongs to the class of AP1/FUL-like group of MADS-box genes and was termed as DtpsMADS1(accession No.JQ065097). Real-time quantitative PCR (qRT-PCR) results showed that DtpsMADS1 had obvious expression specificity in different organs; DtpsMADS1 had higher levels of expression in root and leaf at pre-flowering stage and post-flowering stage, meanwhile had lower levels of expression at seedling stage and full-blossom stage; The expression of DtpsMADS1 in inflorescence rachis showed the same tendency as root and leaf; However, only trace expression level was detected in flower organs. The results suggested that DtpsMADS1 could be involved in regulating the flowering process, not in floral morphogenesis.