Analysis Of Transcriptome Of Interaction Between Cotton And Fusarium Oxysporum And Mining Of Pathogenicity Related Genes

【Object】Cotton is one of the most important fiber cash crops in China,and also an important oil and high-protein crop in the national economy.Xinjiang is the largest high-quality cotton production base in China.Due to its unique climate conditions,its cotton quality and yield rank first in the country.At present,cotton production has become an important industry in Xinjiang’s agricultural production,but with the rapid expansion of cotton planting area and the extension of continuous cropping years,the occurrence of cotton wilt is becoming more and more serious,which has become a major issue affecting the sustainable development of cotton production in Xinjiang.Cotton wilt is a common soil-borne plant fungal disease.The pathogen is Fusarium oxysporum wilt specialized fungus.Because of its tenacity and rapid spread,it does great harm to cotton production.The transcriptome sequencing(RNA-Seq)of the new generation of high-throughput sequencing technology provides an important means for people to understand the molecular mechanism of the interaction between host and pathogen,but the molecular mechanism of the interaction between Fusarium oxysporum and host is still insufficient,especially the molecular mechanism of the interaction between cotton and Fusarium wilt is still lacking.Therefore,it is urgent to study the molecular mechanism of the interaction between cotton and Fusarium wilt,so as to lay a foundation for screening target genes and further using HIGS technology to create cotton disease resistance resources and cotton disease resistance breeding.【Methods】Using the resistant and susceptible cotton root tissue and pathogenic bacteria infected by Fusarium oxysporum for 48 hours as materials,using RNA-seq sequencing technology(1)to study the gene expression differences between resistant and susceptible cotton varieties before and after infection by Fusarium oxysporum,and to enrich these differentially expressed genes into the metabolic pathway involved,and screen the cotton disease-resistant genes induced by Fusarium oxysporum;(2)To study the changes of transcription level of Fusarium oxysporum after infecting different resistant varieties,and screen the key pathogenic genes of Fusarium oxysporum;(3)Use bioinformatics software to analyze disease-related genes,design and synthesize asi RNAs,silence genes containing the sequence,and analyze the effect of target gene silencing on cotton disease resistance.【Results and conclusions】1.When Fusarium oxysporum infected cotton resistant varieties,5196 genes were differentially expressed in resistant cotton varieties,4162 genes were differentially expressed in Xinhai 14,and 10022 genes were differentially expressed in Xinhai 42.The GO function enrichment analysis of the differentially expressed genes of the disease-resistant and disease-sensitive varieties showed that the DEGs of Xinhai 42 had significantly up-regulated items such as the response to biological stimulation,the response to injury,and protein kinase;KEGG analysis found that both resistant and susceptible varieties had the most significant enrichment in the two items of plant hormone signal transduction and plant-pathogen interaction,and involved the largest number of genes.Then,48 genes with large differences among resistant and susceptible varieties were screened out from cotton,which may be closely related to the resistance of sea-island cotton to Fusarium wilt.2.When Fusarium oxysporum infected cotton resistant varieties,a total of 4638 differentially expressed genes were screened,of which 2726 genes were differentially expressed in the pathogens infected with resistant varieties,930 genes were differentially expressed only in the pathogens infected with Xinhai 14,and 982 genes were differentially expressed only in the pathogens infected with Xinhai 42.Through enrichment analysis,it was found that the GO functional categories after Fusarium oxysporum infection of resistant and susceptible varieties were mainly related to heterocyclic metabolic process,RNA processing,membrane components,molecular function regulation,catalytic activity regulation,protein folding,ATP binding and other categories;Through KEGG analysis,it was found that the top three pathways after Fusarium oxysporum infection of resistant varieties were carbon metabolism,amino acid biosynthesis and protein processing in endoplasmic reticulum.Subsequently,25 genes with large difference in the time of infection of resistant and susceptible varieties were screened from Fusarium oxysporum.From these genes,genes that play an important role in the virulence and pathogenicity of Fusarium oxysporum can be selected as candidate genes for the pathogenicity of Fusarium oxysporum.3.The mycelial growth,colony growth,growth rate and spore production of the strains containing small asi RNAs fragments were inhibited to a certain extent.When the concentration of small asi RNAs fragments was 100 n M,the targeted inhibition of FoP450-3,FoLNBE and FoBRG1 was the best.The silencing of FoP450-3,FoLNBE and FoBRG1 genes can inhibit the growth of Fusarium oxysporum,but after the silencing of FoP450-3 and FoLNBE genes,the pathogenicity of Fusarium oxysporum is significantly reduced,while when the FoBRG1 gene is silenced,the pathogenicity of Fusarium oxysporum is reduced slightly.