Cloning And Functional Analysis Of DiaMYB In Dendranthema Indicum Var. Aromaticumu

Dendranthema indicum var. aromaticum is a herbaceous perennial plant characterized by special scent, which is the important aroma resource in genus Dendrathema and found in Shennongjia, Hu Bei province, P. R. China. The flavor matter in plants usually consists of several chemical components, whose pathway of the biosynthesis is regulated by many enzymes, so it is restricted to only increase numbers of copies of key enzymes’genes. Whereas, alteration in the expression of transcription factor genes normally results in dramatic changes tc a plant. MYB gene is associated with the main aroma components terpenoids secondary metabolites.Therefore, It is vital to carry out the gene engineering research about aroma substance metabolism in Dendranthema indicum var. aromaticum,so that it can contriubute to improve the aromatic character of some important ornamental chrysanthemum flowers,and cultivate excellent chrysanthemum varieties significantly. The main findings are as follows:1. In this study, the full length cDNA of a MYB (named DiaMYB) gene was isolated from Dendranthema indicum var. aromaticum. The DiaMYB cDNA was about1300bp, and the open reading frame(ORF) was948bp, encoding a protein of315amino acid residues with molecular mass of34.57kDa and theoretical Pi was9.04. GenBank BlastX search revealed that DiaMYB shared a high degree of homology with proteins of the R-type MYB family, and the close relatives of DiaMYB were CmMYB2from Dendrathema grandiflora(95%identity). It is supposed that the function is associated with hormone response.2. We constructed the plant expression vector of PCAMBIA1301-MYB with the method of double enzyme digestion. The gene plant expression vector of DiaMYB was transferred into Arabidopsis thaliana using Agrobacterium tumefaciens infection. We get6transgenic lines of DiaMYB by Hyg screening to the transgenic arabidopsis.It was suggested that We have transferred the genes of DiaMYB into Arabidopsis thaliana successfully performed by RT-PCR detection from transgenic Arabidopsis thaliana.3. With wild-type Arabidopsis thaliana by contrast,the study suggests that the quantity of transgenic plant’s epidermal hair under the microscope reduce largely.And we can find it has few epidermal hairs in the same field of vision from transgenic Arabidopsis thaliana.When we choose10visions for statistical analysis of the differennt numbers,we receive it is completely different between wild-type plants and transgenic ones.There is no more epidermal hairs on the surface of transgenic plant’s leaf,while there is no one in the opposite side.So,we conclude that the excess expression of DiaMYB transcription factor gives rise to restrain the form and morphogenesis of epidermal hair, furthermore, DiaMYB gene is associated with the formation of plant’s epidermal hairs.