Genome Sequencing And Assemble Analysis Of Madicago Sativa

In recent years,with the continuous development of genome sequencing technology,more and more plant genome sequences have been improved.Through genome sequencing,the function of plant genes can be systematically analyzed.medicago sativa has excellent agronomic characters,is the most widely planted forage crop in the world,and has the reputation of "king of forage".In China,medicago sativa growth is mainly concentrated in the northern regions,which are prone to low temperature damage due to cold climate,resulting in reduced production of medicago sativa and greatly reducing its production efficiency.As one of the local medicago sativa varieties,zhaodong alfalfa has good cold resistance.Therefore,this study took zhaodong alfalfa as the main research material to carry out genome sequencing,assembly and annotation and obtain the draft genome.Four other medicago sativa varieties: Algonquin,WL168,WL525 and WL440 were resequenced,and credible cold resistant SNP was mined.Meanwhile,AP2/ERF transcription factors of medicago sativa were excavated and medicago sativa AP2/ERF gene regulation network was constructed,so as to systematically analyze the regulation mechanism of AP2/ERF transcription factors in cold stress resistance of medicago sativa.The main research results are as follows:1.Genome assembly and annotation analysis of medicago sativaBy high-throughput sequencing,the medicago sativa genome size was estimated to be about 1107 M,and the heterozygosity rate was 1.77%.A set of alfalfa genome sketch was obtained by software assembly.Further annotation and analysis revealed 119194 protein-coding genes,the majority of which focus on biological processes such as signal transduction mechanism,protein post-translational modification,defense mechanism and transcriptional regulation.2.Genetic variation excavation of cold resistance traits of medicago sativaThe whole genome of four alfalfa varieties was resequenced to explore the genetic variation(SNP)among medicago sativa varieties,and 8909604 genetic variations were obtained.Based on the cold resistance data of 5 medicago sativa varieties,82838 SNPs were found to be related to the formation of cold resistance traits of medicago sativa.These SNPs are distributed on 14372 genes,which are mainly involved in the processes of reduction metabolism,transcriptional regulation and signal transduction.Further analysis revealed that AP2/ERF,bHLH,MADS,NAC,MYB,WRKY and other gene families may play a key regulatory role in cold resistance of medicago sativa.3.Molecular regulation mechanism of AP2/ERF transcription factors of medicago sativaThe whole genome of medicago sativa was analyzed and 139 AP2/ERF transcription factors were discovered.The software was used to analyze the gene interaction between alfalfa and model plant arabidopsis thaliana,the gene regulation network of medicago sativa was constructed,and the molecular regulation network of alfalfa was systematically analyzed,which laid a theoretical foundation for the utilization of medicago sativa gene resources in the future.