Bioinformatics Research Of Genome Structure Evolution In Actinidia Chinensis

Kiwifruit is with high vitamin C content fruit.The sequence of it was completed to provide major data for studying the evolution of genome structure and function of kiwifruit.However,the research on the evolution process of polyploidy is vague,especially for the genomic comparison of the ancient polyploidy of kiwifruit.In this study,we used the dicotyledon important reference genome grape and coffee,and used genomic informatics to analyze the evolution of kiwifruit genome structure.It was found that there were more homologous fragments in kiwifruit than grape or coffee,which was 422.And the genes in the homologous fragments was more than two references,which was 8057.Combining genome homologous structure alignment and homologous gene synonymous nucleotide substitutions(Ks)distribution,the duplication form of kiwifruit genome was defined.Evidence of two tetraploidization events in kiwifruit was found,and the time of events was determined,with one occurring 50-57 million years ago and the other 18-20 million years ago.We constructed a collinear gene list of kiwifruit associated with polyploidy and speciation,as well as the subgenomes of two tetraploidization events.By comparing the differences of repeat gene retention/loss and the gene expression between different subgenomes,it was found that there was no significant difference between subgenomes.This study revealed that the two whole genome duplication of kiwifruit might be autopolyploid events.Based on the Ks distribution of genes produced by the core-eudicot-common hexaploidization(ECH),it was found that the evolution rate of kiwifruit was slowest.It was inferred that autopolyploid might reduce the evolution rate.In addition,it was found that polyploidization promoted the expansion of key genes in VC pathway in kiwifruit,which may be an important factor in promoting the ability of VC synthesis.The project reveals the scale and nature of polyploidy in kiwifruit,and provides important comparative genome resources for genome research of kiwifruit species.It also provides genome-wide understanding of the evolution of VC pathway in kiwifruit,which has important scientific significance and potential economic value.Figure29;Table16;Reference 67...