The EoNPV Genome Analysis And Study On The Toxicity Difference Between Two Sibling Species Of Tea Genometrid

Ectropis obliqua nucleopolyhedrosis virus?EoNPV?is an important pathogenic microorganism that can infect and cause the death of tea geometrid.The main leaf-eating pests in the tea plantation are two sibling species of Ectropis grisescens Warren and Ectropis obliqua Prout,both of which are very similar in shape and feeding habits,and have been considered as the same species for a long time.Therefore,there may be differences between the current research results and the real situation.Especially when the EoNPV is used as a biological pesticide to control E grisescens and E obliqua in tea plantation.There should be different control methods against these two sibling species.Therefore,in this study,the Oxford Nanopore of three-generation sequencing technology was firstly used to determine the whole genome sequence of the EoNPV.The LD₅₀ of EoNPV to E grisescens and E obliqua were compared by leaf disk feeding method.The difference of virulence of two sibling species to EoNPV was determined.Then the mortality rate and LD₅₀ values of EoNPV to two sibling species were also compared with those of H-EoNPV,which is a highly efficient strain and was selected from the previous project.This provides a scientific basis for the field control of two sibling species of tea geometrid.1.Genome sequencing and analysis of the EoNPV accoding to the sequencing results,the full length of the genome sequence of the EoNPV is 132,043 bp,in which the content of G+C is 37.51%.The functional genes of the genome were predicted,and 106 open reading frames?ORFs?were obtained.The G+C content of the ORFs region in the genome was 38.96%,which was similar to the overall G+C content.There are currently 78 genes complete annotations.A total of 3 homologous repeat regions?hrs1,hrs2and hrs3?were detected in the EoNPV genome.Two ORFs may be unique to EoNPV,as no homologous sequences have been found in other baculoviruses.2.Virulence difference of EoNPV of E grisescens and E obliqua.The research finding suggest:?1?The mortality rate of E obliqua was higher than E grisescens at the same time after feeding with the same dose;?2?The LD₅₀0 and LT₅₀ of E obliqua were less than that of E grisescens.The LD₅₀0 of E grisescens is 28.9 times that of E obliqua.When feeding with a dose of 2×10⁷?PIB/larvae?,the LT₅₀of E grisescens Warren is about twice that of E obliqua.At a dose of 2×10⁶?PIB/larvae?,the LT₅₀ of E grisescens is about 1.35 times that of E obliqua.The results show that,it is concluded that EoNPV is more toxic to E obliqua than E grisescens.3.The difference of virulence between H-EoNPV strain and the EoNPV strain to the third-instar E grisescens was compared.The research finding suggest:?1?The virulence of the H-EoNPV is different from EoNPV.?2?The mortality rate of H-EoNPV on E grisescens is significantly higher than that of EoNPV.?3?The LD₅₀ and LT₅₀ of EoNPV were higher than those of H-EoNPV.The LD₅₀0 of EoNPV is 3.1-25.8 times than that of H-EoNPV.The results show that,H-EoNPV strains has higher toxicity to E grisescens than EoNPV.The virulence of H-EoNPV to E grisescensof different geographical populations was also different.