Molecular Cloning And Functional Analysis Of Stress-Tolerance MYBTFs And Related Genes From Chimonanthus Praecox L.

Chimonanthus praecox L.(wintersweet) is a winter-flowering deciduous shrub that originates from China. They bloom in all kinds of different growth conditions owing to some unique characteristics, such as being able to resist to abiotic (cold, drought et al.) and biotic stress. Since MYB transcription factors (TFs) play an important role in plant stress tolerance, TFs from Chimonthus praecox are inferred to take part in the pathway of responsing to environmental stress. In order to investigate the expression and regulation mechanism of MYB transcription factors in Wintersweet, on basis of wintersweet transcriptome library, we predicted and cloned the candidate MYB genes and studied their possible functions through bioinformatics and molecular methodology. Stable over-expression transformations of tobacco and Arabidopsis thaliana via Agrobacterium were also done. The main results were as follows:1. Based on transcriptomic express sequence tags of the flowers during flowering stage,175,67and60unigenes that might be involved in MYB, bHLH and WD40function, respectively, were analyzed. Their partial amino acid sequences were used to construct phylogenetic trees with Arabidopsis.2. We cloned seven full length MYB genes and one abiotic stress related genes using RACE and TAIL-PCR techniques. The bioinformatics analysis implied that there were six R2R3-MYB transcription factors, one MYB-related transcription factor, one WD40transcription factor. It is supposed that they may have functions of cold resistance, signal transduction, formation of trichomes, the development of petal’s epidermis cell and resistance to abiotic stress.3. Six over expression vectors were constructed successfully, and some transgenic plant were validated according to PCR results. Amongst them, one CpMYB3strain in four transgenic Arabidopsis have obvious phenotype modification.