[Objective] This study aimed to clone ubiquitin-conjugating enzyme gene TaUBC4 from different wheat cultivars and thus analyze their phylogenetic relationship.[Method] The UBC4 coding sequences were cloned through reverse transcription PCR （RT-PCR） from 21 wheat varieties.After sequencing,the UBC4 sequence in wheat cultivar Zhongguochun （GenBank accession No：M28059） was selected as the reference gene,to analyze the mutation frequency and evolutionary distance in the CDSs and corresponding amino acid sequences of the different wheat cultivars.Moreover,the phylogenetic tree based on the amino acid sequences of these TaUBC4 genes were constructed,involving the homologous sequences of TaUBC4 in eight other monocots.[Result] TaUBC4 sequence was highly conserved because the similarity in DNA sequences of the wheat varieties was over 94％,while that in amino acid sequence was over 96％.And the amino acid sequence difference only can be seen at two sites among some varieties.Phylogenetic tree constructed revealed the evolutionary relationships among these wheat varieties.[Conclusion] This study reveals the polymorphism and evolutionary characteristics in the nucleotide and amino acid sequences in different wheat varieties,which lays foundation for investigating the evolution and biological function of TaUBC4 gene.In addition,the phylogenetic tree constructed provides theoretical references for the classification of the wheat varieties with complicated background.
