Function Analysis Of PF40 Gene In Millet (Tetaria Italica)

The aerial architecture of flowering plants is determined to a large extent by shoot growth and shoot branching arising from the initiation and growth of axillary meristems. The axillary branching process generally involves two developmental stages: the formation of axillary meristems in the leaf axils and subsequent axillary bud growth. In many plant species, includingArabidopsis, the growth of axillary meristems is inhibited by the primary inflorescence, a phenomenon generally known as apical dominance. Recently, the isolation and characterization of genes and mutants with altered shoot branching patterns has been used to study this phenomenon, through the molecular and genetic analysis has been given invaluable information of defective in the branching pattern . However, the underlying regulatory mechanisms and genetic pathways have not yet been established. It is obvious that additional informative genes are required for analysis before the mechanisms underlying this process can be unraveled.Initially, a polyclonal antibodies was used to screen the cDNA expression library to isolate PF40 gene from millet. Sequence analysis revealed that the PF40 gene contained an open reading frame (ORF) encoding a protein with 75%-35% sequence identity to the ZIPs (zinc or iron transporter proteins) gene family. Software analysis of the PF40 gene character showed that PF40 protein had a eight trans-membrane region structure, PF40 protein was also rich in leucine (18.4%) and the protein was a hydrophobic protein.Southern hybridisations showed that the PF40 gene was present in one or few copies in the millet genome. Moreover the PF40 gene was ubiquity distributed in cereal crop genome. Dicots such as tobacco and tomato do not have the PF40 homolog gene, but we found its homolog gene maybe present in Arabidopsis genome. Northern blot analysis showed the PF40 gene was expressed in all tissue of plant but predominantly in very young tissue such as hypocotyl and bud,the result was further tested by fusion PF40 with GUS gene.Used different hormone to induce the PF40 gene showed it was regulated by 6-BA and GA.To gain more information about the function of PF40 gene, plant expression vectors with sense and anti-sense and knockout PF40 gene promoted by 35S promoter were constructed. Millet and tobacco were transformed with the thrt'e plant expression vectors. Our observations with transgenic plants showed that the PF40 gene affected the growth of lateral shoots developing in the basipetal pattern early after floral transition.Analysisd the transgenic plants showed the PF40 gene can reduced the apical dominance of both millet and tobacco. Our results provided direct evidence that PF40 gene play a role in the tissue development ,with knockout this gene the lateral buds were not visible.The plant hormones auxin and cytokinin appear to play a major role in controlling this process, Therefore, the concertrition of auxin and cytokinin was measured, However, the concentration of the two hormone was variation a little in transgenic plants,but the ratio of the two was more than 5 fold in the PF40 gained function plant than that in wild type.Furthermore the PF40 gene effected differentiationof the vascular bundles in different transgenic plants, results showed the PF40 could change both xylary fibers and vessel.Result from transgenic plants and the blast PF40 in genbank given the hits that PF40 gene may through regulated the development of vascular tissue ,and then influence the absorption or transport of some mental, this would change the hormone of plants ,so the PF40 gene may function as a developmental regulators.