| Dendrolimus superans is an important pest in Northeast China,which has caused serious harm to the forestry in North China.In this study,the whole genome of larva samples of D.superans was sequenced for three generations,and the genome data of D.superans were obtained by assembling annotation.Through comparative genomics analysis,the phylogenetic status of D.superans,the expansion and contraction of gene family and the positive selection pressure on each gene were explored,and the adaptive evolution of D.superans was explained from the genomic level,It lays a theoretical foundation for the design of green control agents with D.superans gene as the target in the future.The main results are as follows:1.The genome of D.superans was sequenced and 5,538,772 cleanreads were obtained.After assembly,the genome with a length of 619.18 mb was obtained.Its Contig N50 was8.99 Mb and the GC content was 35.92%;14332 genes were predicted and 96.76% of the functional genes were successfully annotated.Its Contig N50 ranks high in the published genome,confirming the reliability of the data.2.The results showed that Lepidoptera insects clustered in a large branch in the phylogenetic tree,and D.superans were in the moth branch in the moths branch.The genetic relationship between D.superans and Manduca sexta is the closest,and the common ancestor of M.sexta,Bombyx mori and D.superans differentiated in the early Cretaceous about 83.71 million years ago.3.In the genome of D.superans,there are 85 expanded gene families and 71 contracted gene families.Among the gene families related to the adaptive evolution of D.superans,six detoxification and metabolism gene families expanded and six detoxification and metabolism gene families contracted,three chemosensory gene families contracted.In the odorant receptor gene family,Lepidoptera sex pheromone receptor gene family has gene loss in the genome of D.superans.Based on the above data,we combined 47 ors genes of D.superans with 67 ors genes of the published Dendrolimus punctatus,related species D.superans to construct an evolutionary tree,and obtained 4 candidate PR genes of D.superans through homology analysis,It shows that PR gene has been lost and evolved independently in Dendrolimus insects.4.There are 35 genes in the genome of D.superans under obvious positive selection pressure in evolution,including 2 genes related to the resistance of D.superans to deltamethrin insecticides,7 genes related to the growth,development and life activities of D.superans,and 5 genes related to the transmission of genetic information.The adaptive evolution of these genes can help D.superans avoid the interference of deltamethrin insecticides or resist cold conditions,so as to ensure its normal physiological activities.On the basis of obtaining the genome of D.superans,an important forestry pest in northeast forest area,this study carried out gene family expansion and contraction,homology analysis and selection pressure analysis of its related genes.The relevant results further explain the adaptability of D.superans to its living environment from the genomic level,and provide targets such as detoxification metabolism and chemical sensing genes,which lays a theoretical foundation for the development of D.superans pest management strategy with genes as targets in the future. |
