The Cloning And Sequence Analysis Of FT Homologous Gene In Several Rosaceae Plants

In recent years, through the study of flowering genes in the model plants, such as Arabidopsis thaliana, rice and petunia, scientists have gradually improved the complex gene regulatory networks, and recognize the role of FT gene which plays a key factor in the networks. However, studies on the FT gene are only limited to the representation of few species and just a few laboratories keep on limited explorement, few further studies of the FT are fround through families and genera, and studies of Rosaceae species was only confined to apple and peach, etc. To better understand the FT gene polymorphism and the relationship between flowering time and the FT gene regulatory elements or other informations, the following main results are obtained in this study through rosaceae materials, such as Pyracantha fortuneana, Prunus mume, Photinia serrulata L., Prunus persica, Spiraea cantoniensis L., Rosa chinensis, Fragaria×ananassa.1. We obtained the FT gene conserved fragments of Fragaria×ananassa, Rosa chinensis, Prunus mume, Prunus persica, Photinia serrulata, Pyracantha fortunean by homology cloning. Of which Pyracantha fortunean 976bp, Fragaria×ananassa 319bp, Rosa chinensis 316bp, Photinia serrulata 979bp, Prunus persica 653bp, Prunus mume 648bp. Blastn analysis of various species shows that the amplified fragments is the expected FT conserved sequences, and further detailed information by sequence alignment and the FT gene structure confirmed that the sequence of FT conserved fragments is confined between the third and fourth exon.2. After splicing Tail-pcr amplified sequences, we obtained FT gene sequence information of strawberry, rose, plum, photinia, pyracantha from nuclear DNA, the sizes respectively_are 2522bp,2213bp,2025bp,3036bp,2837bp.And 5 ’end of FT gene plum is 1210bp,3’end of 350bp, rose 5’end of 257bp,3’end of 822bp, strawberry 5’end of 171bp,3’end of 1247bp, photinia 5’end of 341bp.3. Full-length of FT gene was obtained from the DNA of strawberry, rose, plum, photinia through specific primers amplification, and FT gene sequence information was confirmed by alignment with the spliced sequences.4. After extracting the RNA of the two species, strawberry and rose, we obtained FT gene informmation on the level of cDNA through specific amplification. The comparison of intron and exon with the full-lengh FT sequences of strawberry, rose, plum, apple explained that FT gene exon is more conservative, particularly the second and third exons. There is also a conservative region between the intron of rosaceae subfamily species. All the 3 intron boundary have the GT-AG sequence feature. The FT gene of strawberry encoding 199 amino acids and rose encoding 190 amino acids.The Phylogenic analysis of FT proteins from the 14 kinds selected plants shows that the evolution of FT gene is in a small degree, the genetic relationship of FT protein between strawberry and rose are closer, and also have a close genetic relationship of other species of rosaceae. However, they have a distant genetic relationship with Arabidopsis thaliana and rape.5. Try to analyse the FT gene expression in different species of rosaceae. Semi-quantitative RT-PCR of strawberry showed that FT gene in the roots basically has no transcript, while there has both in leaves and stems, although the stem has less.