Joint Analysis Of Head Transcriptome And Methylome In Silkwor M With Different Feeding Habit On Artificial Diet

Sericulture is a traditional agricultural industry in China,but with the advancement of socio-economic and agricultural modernization,sericulture also urgently needs to be transformed and upgraded.Artificial feed sericulture will be an important direction for the development of sericulture in China.At present,there are insufficient varieties of artificial feed adaptive silkworms in China,which seriously restricts the promotion of this technology.Therefore,improving the feeding ability and adaptability of silkworms to artificial feed is an urgent scientific problem to be solved.The research on the basic theoretical basis of silkworm feeding habits is relatively mature,but the key factors and influencing mechanisms that cause differences in feeding habits among different silkworm varieties have not been fully confirmed.Therefore,in-depth research on the differences in feeding habits of silkworms and their regulatory mechanisms has important scientific significance and practical value.This study used silkworm strains with different feeding habits on artificial feed(Jing song B good feeding preference,Jing song B bad feeding preference)as materials,Through the combined analysis of transcriptome sequencing and whole genome methylation sequencing,the genes with different levels of DNA methylation and transcriptional expression were screened,and the expression characteristics and functions of aldehyde dehydrogenase gene and odor receptor gene were studied.The research results provide basic data for revealing the molecular regulation mechanism of feeding difference of different artificial diet rearing silkworm strains,and also provide candidate genes for improving feeding,which is of great significance for promoting the research of functional genomics of silkworm.The main results of this study are as follows:1.A comparative analysis of transcriptome of the head of the 3rd instar silkworm fed on different artificial diets was carried out.The obtained transcriptome sequencing data is of qualified quality and high coverage;682 differentially expressed genes were identified,of which 265 were upregulated and 417 were downregulated.GO and KEGG functional enrichment analysis was conducted on differentially expressed genes,and the results showed that differentially expressed genes were mainly involved in biological processes such as metabolism,cell composition,and binding.They were significantly enriched in 20 metabolic pathways,from which 3 pathways related to feeding habits were obtained: phenylalanine metabolism pathway,arginine biosynthesis pathway,and cytochrome P450 metabolism pathway.2.The whole genome DNA methylation sequencing comparative analysis was carried out on the head of the 3rd instar silkworm of different artificial diet feeding habits,and the sequencing data obtained met the requirements and the sequencing quality was qualified.Three forms of methylation sites(m CG,m CHG,and m CHH)were detected,but their expression patterns and transcriptional elements showed certain differences.Further analysis and statistics of DMR in the three forms of differential methylation regions showed that the number of DMR in CG site was the largest,followed by CHG site,and the number of CHH site was the smallest.Methylation occurred in different transcription elements of DMR,indicating that DNA methylation was non random in different artificial feed feeding strains.This study also found that the most methylation occurred in intron and exon regions,so it is speculated that DNA methylation may participate in gene regulation and modification in silkworm with different feeding habits.Simultaneously analyzing DMP,a total of 64 genes underwent promoter methylation,including 30 high methylation genes and 34 low methylation genes.Comparing DMP with KEGG database,it was observed that DMP is involved in 33 pathways,and three pathways that may affect feeding habits were identified:vitamin digestion and absorption pathway,Hippo signaling pathway,and ABC protein transport pathway.3.Genome wide methylation and transcriptome sequencing data were analyzed jointly.69 genes were identified to have differential expression at both the transcription and methylation levels.GO analysis of these differentially expressed genes revealed that they were mainly enriched in cellular and binding processes.KEGG pathway analysis revealed that they were mainly enriched in metabolic pathways such as histidine metabolism and thiometabolism.4.Functional analysis of aldehyde dehydrogenase gene(LOC101735616)and odor receptor gene(LOC110385248)with high degree of methylation screened by transcription level and methylation level and involved in multiple metabolic pathways,using 5-Aza dc and RNAi technology,found that the amount of gene table and body mass of JBg and JBb changed,suggesting that the aldehyde dehydrogenase gene and odor receptor gene affect the feeding behavior of B.bombycis jingsong strain B through methylation,The odor receptor gene and aldehyde dehydrogenase gene may be key genes causing differences in feeding habits of the silkworm Jingsong B strain.