The existence of a long juvenile phase is found seriously to affect the early-stage economic benefits of later mature walnuts (Juglans regia L.). Studies on LFY, a key gene controlling floral transition and flower differentiation, may be helpful in solving the problem. This study reports the identification and characterization of a JrLFY gene from Juglans regia L., a homolog of FLORICAULA/LFY. The gene was isolated from flower buds of precocious walnut cultivar Zhonglin No. 5 by RT-PCR and RACE. The cDNA sequence of JrLFY (GenBank accession no. GU194836) was 1496 bp and contained an ORF of 1158 bp. Its corresponding genomic sequence (GenBank accession no. HQ019159) showed that the JrLFY contained three exons and two introns. The predicted amino acid sequence of the gene consisted of 385 amino acids and had a conserved region in the C-terminal when being aligned with sequences of other LFY homologs. Phylogenetic analysis showed that the LFY protein of walnut was close to those of hickory and chestnut. These studies will lay a foundation for understanding the mechanism of early fruiting and preparation for transfer of the JrLFY as a transgene to later mature walnuts.
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