Isolation And Characterization Of Myb And Dof Genes In Hexaploid Wheat (Triticum Aestivum. L)

Regulation of gene expression at the level of transcription controls many crucial biological processes including growth and development, stress response, signal transduction and disease resistance. A number of different factors are required for the processes of transcription, in which the transcription factors play an important role. The study of transcription factor in wheat lagged behind, in this article, the biggest transcription factor family, Myb and a plant-specific transcription factor family Dof were analyzed by using degenerate primers PCR and in silico cloning. The main results are as follows:1) Twenty-three Myb genes fragments which are expressed in the root, stem, leaves and seeds were obtained by degenerate-primer PCR. Structure analysis showed that the structure of the DNA-binding region (R2R3 region) of most Myb members is W-x(19)-W-x(19)-W-x(12)-F-x(18)-W-x(18)W, which indicated that some unique Myb members exist in wheat.2) Six nearly full-length Myb cDNAs, TaMybl-TaMyb6 were obtained by in silico cloning. The structure prediction of deduced amino acids showed that they include an intact HLH DNA-binding domain. In addition, TaMyb2 and TaMyb4 have typical nuclear localization signal, and some members contain one or more activation domain.3) The spatial-temporal expression pattern of six members in different plant organs was studied. The results indicated that the expression level of TaMybl-TaMyb6 six genes differed in root, stem, leaves and seeds of different developmental stages. Gibberellins treatment and PEG stress experiments indicated that the expression of some Myb members are strongly affected by PEG stress in trefoil stage, but only TaMybi is inhibited by Gibberellins (GA) treatment.4) The expression analysis of TaMybl-TaMyb6 between parent and hybrid showed different expression patterns, including dominant expression, reduced expression in hybrid in vegetative tissues (root, stem and leaves) and seeds of 6-12 days after pollination.5) The preliminary transformation experiment of TaMybl and TaMyb2 to Arabidopsis thaliana showed that over expression of TaMybl and TaMyb2 could cause the change of leave's color, and mortality to some plants.6) A TaDof1 gene has been cloned from wheat by in silico cloning. The expression pattern of the TaDofl gene in different organs and its relative expression level between wheat hybrids and their parents were also investigated.