Cloning and functional analysis of the gene in L.

The gene plays an important role in the formation of apical meristem and organ edges in plants. The apical meristematic tissue of () is associated with cold resistance, however, the role of the gene in cold resistance of is unclear. In this study, we used bioinformatics software to analyze the structure of gene, real-time fluorescence quantitative PCR to detect the expression level of , constructed transgenic by the flower dipping method and subcellular localization for functional validation. The results showed that, we isolated a 1104 bp open reading frame of from the winter cultivar 'Longyou 7'. The BrCUC2 contains a highly conserved domain belonging to the NAM superfamily. Its homologus genes contain similar conserved motifs and are closely related to (), and the N-terminal of amino acid sequence contains NAC domain. BrCUC2 protein was localized in the nucleus and self-activation tests showed that pGBKT7-BrCUC2 had self-activation. Tissue-specific expression analysis and promoter β-Glucuronidase (GUS) activity showed that had high expression levels in growth points and leaf edges, stems and growth points. After low-temperature stress, showed greater expression in 'Longyou 7,' which presents strong cold resistance and concave growth points, than in 'Longyou 99,' which presents weak cold resistance and protruding growth points. promoter contains multiple elements related to stress responses. overexpression revealed that the phenotype did not differ from that of the wild type during the seedling stage but showed weak growth and a dwarf phenotype during the flowering and mature stages. After low-temperature treatment, the physiological indexes and survival rate of -overexpression lines of () were better than those of the wild type within 12 h, although differences were not observed after 24 h. These results showed that improved the low-temperature tolerance of transgenic within a short time. It can provide a foundation for the study of cold resistance in winter .