Cloning And Expression Analysis Of MYB Family Genes In Ginkgo Biloba

MYB transcription factor is one of the largest families in plants, which involved in regulation of cell differentiation, responding to biotic and abiotic stresses, also regulation of plant growth and development and the formation of flower, leaves and other organs. Ginkgo biloba is the endemic tree species of China. Ginkgo flavonoids have many unique pharmacological effects of traditional Chinese medicine, especially in the treatment of cardiovascular and cerebrovascular diseases. Most of MYB transcription factors were reported to have ability to regulate the metabolism of flavonoids. In the paper, some new genes MYB transcription factors were isolated and characterized from Ginkgo biloba. The main results of the study are as follows:1. According to the consvered regiongs which encoding the MYB DNA binding domains in plant MYB genes, we designed a pair degenerate primers. Three novel genes encoding MYB transcription factors, Gb MYB1, Gb MYB2 and Gb MYB3 were isolated by using RT-PCR and RACE-PCR. Comparison of deduced amino acid sequences found that the core sequence of Gb MYB1 and Gb MYB2 is similar to Rc MYB, Gb MYB3 is similar to Pt MYB. Based on those information, we can speculate that they are typical R2R3-MYB transcription factors which have two MYB domains respectively.2. The cutting seedings of two years of Ginkgo biloba were treated under Na Cl solution stress, ABA stress and low temperature stress. Expression differences of the Gb MYB genes of Ginkgo biloba were performed by real-time quantitative PCR. The results of expressing analysis shown that the expression of Gb MYB have increased,under Na Cl solution stress, ABA stress and low temperature stress. The total contents of flavonoids have increased under Na Cl solution stress, ABA stress and low temperature stress. We can speculate that these Gb MYB genes have ability to regulate the metabolism of flavonoids.3. Construction and transformation of the expression vector of Gb MYB gene using gateway technology by transgenic Arabidopsis plants. The overexpression of Gb MYB gene play an important role in regulation of plant growth, The plant height of transgenic Arabidopsis plants were superior to that of wild type and empty plasmid control. The results indicated that the overexpression of Gb MYB1 gene, Gb MYB2 gene and Gb MYB3 gene could improve resistance to Na Cl solution stress of transgenic Arabidopsis plants.