The Research Of Function And Evolution Mechanism Of Soybean MYB Gene Family

MYB gene family is one of the largest families of plant transcription factors and plays important roles in plant development, metabolism, stress resistance and other aspects. We have identified MYB genes in Brassicaceae(Arabidopsis thaliana) and Leguminosae(Glycine max, Phaseolus vulgaris, Medicago truncatula and Lotus japonicas). Using the conserve domain of MYB gene family as a query, we characterized 192 MYB genes in Arabidopsis thaliana, 463 MYB genes in Glycine max, 263 MYB genes in Phaseolus vulgaris, 155 MYB genes in Medicago truncatula and 183 MYB genes in Lotus japonicas. These MYB genes distribute unevenly in different or within chromosomes among species and in a specific species. The orthologues of MYB genes show extensive differences between species but less in a specific species. We found a new domain(W-W-X) of MYB genes and a new sub-type MYB gene, which has a larger interval between MYB domains. It suggests that there is a new evolution pathway of MYB gene family.According to the phylogenetic analysis, we found that five studied species shared 38 common clades, while four Leguminosae species shared 58 common clades. Every species has specific clades(9 in Glycine max) and specific genes(13 in Glycine max). We found that most of MYB genes in 38 common groups clades of five species undergo purify selection except 6 clades went through positive selection. Comparing the transcription pattern of R2R3-MYB genes between Arabidopsis thaliana and Glycine max, we found that soybean orthologous MYB genes manifested three types' changes of gene expression comparing the corresponding Arabidopsis MYB gene.Using the whole genome re-sequencing data of 31 both wild soybean and cultivated soybean, we found that 7 MYB genes of soybean involved in differentiation of wild soybean and cultivated soybean, which Fst values are above 0.9. Comparing the nucleotide diversity of MYB genes among 7 differentiation relating MYB genes and 13 soybean specific MYB genes between wild soybean and cultivated soybean, we found that 12 of them showed more variations in wild soybean than in cultivated soybean. These results prompt that MYB genes experience strongly artificial selection during soybean domestication.We re-sequenced the genome of Hedou 12 and identified 49,267 INDELs between Williams82 and Hedou 12. 248 INDEL polymorphisms were vailidated by PCR and there were 169(68%) of them could be developed as INDELs markers. Four gamma ray induced mutants(MSE287-5, MSE308-2, MSE343-23, MSE402-3) were alsore-sequenced to characterize the mutations in their genomes. Several candicdate deletions have already detected in these mutants. Further experiment is still performing to verify the candicdate mutations. We got the deletion region correlation with the mutant phenomenon and improved the foundation for the relationship between gene and phenomenon.Comparing the AP2/ERF gene family, we analyzed the evolution mechanism of AP2/ERF gene in soybean. After analyzing the transcriptome of seed in soybean, we got 10 clusters of expression patterns. This work prompted the evidence for the research that understand the role of AP2/ERF genes during the development of the seed in soybean.Comparing the evolution of WOX2,8,9 genes in Brassica, we comfirmed that the evolution mechanism of WOX2,8,9. We found that BnWOX2 and BnWOX9 expressed in suspensor and BnWOX8 expressed in proper, using semi – quantitative test in supensor and proper. It suggested that the orthologous genes of WOX genes had the similar expression patterns and the paralogous genes of WOX genes had different expression patterns.