Clausena lansium, Citrus sinensis and Poncirus trifoliata belong to the different genus of Rutaceae. On the basis of LEAFY (LFY in brief) gene sequences of C. sinensis and P. trifoliata, a pair of 21 bp primers was designed and used to amplify about a 2 300 bp DNA fragment from C. lansium by PCR. The DNA fragment was cloned into pMD18-T vector and then sequenced. The sequence analysis showed that the genomic DNA clone with 2 346 bp contained a complete coding sequence of LFY homologous gene (ClLFY) which 3 exons were composed of a completed open reading frame and encoded 397 amino acids. The identities of nucleotide sequences of LFY genes between C. lansium with C. sinensis and P. trifoliata were more than 92%, and their identities of amino acid sequences were 95%.The result also indicated that C. lansium LFY gene was one amino acid less than the LFY homologous genes from C. sinensis and P. trifoliata.The research laid a sound foundation for studying the regulation and control in flowering mechanism in C. lansium at the molecular level in the future.
