Molecular Cloning And Expression Analyses Of FT Homologue In Mulberry (Morus Alba L.)

In the life cycles of flowering plants, flowering induction is an important process, plant Flowering Locus T(FT) gene and its homologous genes code a kind of protein named florigen, which acts as long-diatance transportation signal substance, regulates the transform from vegetative growth to reproductive growth,and plays an important role in plant floral induction. Researching on mulberry FT gene is of great significance for breeding and variety improvement. In this study, we gained the complete cDNAof Moms alba FT(MaFT) gene by homology cloning and RACE, and analysed MaFT gene expression pattern by qRT-PCR, the results may improve the research on FT gene function and mulberry flowering mechanism, and provide technical reserves for steeding up the fruit mulberry breeding. The study main consists and conclusion of this study as fellows:1. Tissue culture and rapid propagation of mulberry:Through subculture, strong plant culture and root induction culture of tissue culture of Neo Ichinose triploid and diploid, we optimized different stages’medium prescriptions to cultivate Neo Ichinose for our laboratory. The results showed thet subculture medium of MS+6-BA2.0mg/L, strengthen medium of MS and root medium of1/2MS+NAA0.5mg/L were the optimal medium for Neo Ichinose. Using the above method, we regenetated complete plants successfully, gained experimental plants by domestication and transplanting. Furthermore, we established system of tissue culture and rapid regeneration for mulberry, and laid the technical foundation for mulberry tissue culture and rapid regeneration.2. Morus alba FT(MaFT) gene cloningThrough homology cloning, the complete cDNA of FT homologues was cloned from Neo Ichinose.Sequence analysis showed that the full-length FT cDNA is871bp, contains a519bp open reading frame (ORF), and encoding173amino acids, named MaFT, GenBank record JX462956. Result of acid sequence analysis showed that MaFT protein has the identity of plant FT subfamily protein. Comparing with FT homologues from other plants, the deduced FT shows more than80.0%indentities with those encoded by Ficus carica FT (FcFT), Gossypium hirsutum FT (GhFT), Malus domestica FT (MdFT), Betula luminifera FT(BIFT), pyrus pyrifolia FT (PpFT) and Carica papaya FT (CpFT), and has close genetic relationship with MdFT, PpFT and FcFT.3. Expression analysis of MaFTWe confirmed the temporal and spatial expression pattern by qRT-PCR.1) Tissue expression pattern:MaFT expresses in dormant buds, swelling buds, flowers, juvernile leaves, mature leaves axillary and shoot apexes, highest expression in mature leaves and lowest expression in young leaves.2) Annual expression pattern:the expression level of MaFT in mature leaves rises as the leaves development and reaches peak at the end of June, then reduces to a lower level at the end of august.3) daily expression pattern:the expression of MaFT is influenced by circadian rhythms,MaFT mRNA accumulates rapidly at the end of the day.4) Strain expression pattern:in juvenile plants, MaFT expression level is low and increases year by year.in adult plants and its’adult plants, MaFT has a high expression level, in triploid MaFT has a higher expression level than in diploid,The above results indicate that the expression of MaFT relates to tissue、ploidy、 environmental influence and growth status of mulberry plants.