Cloning and Expression Patterns of PtTFL1.1 and PtTFL1.2 in Populus tomentosa

ZHAO Tianyun¹, YANG Xiong², YANG Xiaoyu¹, CHEN Zhong², AN Xinmin^1*

(¹National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China; ²College of Forestry, Beijing ForestryUniversity, Beijing 100083, China)

Abstract:

Designing primers by homologous cloning and using genomic DNA and cDNA from Populus tomentosa as templates respectively, the paper cloned and isolated two members of TFL1, named PtTFL1.1 and PtTFL1.2. Sequence analysis indicated that the full length of PtTFL1.1 and PtTFL1.2 were 976 bp and 1 090 bp, and the coding sequence length were 525 bp and 522 bp, encoding 174 and 173 amino acids respectively. Both of them contained four exons, three introns and conserved PEBP domain. The predicted amino acid sequences both had critical His88 (H) and Asp141 (D) residues. Homologous protein blast analysis showed that the PtTFL1.1 and PtTFL1.2 shared more than 80% homology in amino acid sequence with Arabidopsis (Arabidopsis thaliana), grape (Vitis vinifera), citrus (Citrus clementina), apple (Malus domestica), and others. Phylogenetic analysis indicated that PtTFL1.1 and PtTFL1.2 belonged to TFL1 clade in FT/TFL1. qRT-PCR suggested that expression patterns of PtTFL1.1 and PtTFL1.2 were different. In PtTFL1.1, the expression level was higher in stem than root and leaf. In addition, with the seasonal photoperiod shortened, the expression of floral buds from different growth periods ap-peared to an obvious decreased tendency. The paper predicted that PtTFL1.1 could participate in photoperiod flow-ering regulation pathway by responding to daylength and it might be a major floral regulator in early floral induc-tion. However, low differential expression of PtTFL1.2 was examined, no matter with the root, stem, leaf and the floral buds from different periods. The research would contribute to exploring the significant role of TFL1 in floral development and floral time regulation in P. tomentosa, which would also lay a foundation for the further study on molecular mechanism of floral regulation in P. tomentosa.