Isolation And Identification Of Monochamus Alternatus Hope Opportunistic Pathogens BRC-CXG2 And Functional Genes Analysis

Serratia is an opportunistic pathogen which is widely distributed in nature and has insecticidal activity against a variety of insects.In this experiment,a strain of BRC-CXG2 was isolated from the illness die Monochamus alternatus Hope by tissue separation.A strain that causes disease was isolated and named BRC-CXG2.The morphology of BRCCXG2 strain was observed and its morphological characteristics were identified.On this basis,16 S r DNA base sequence was determined,phylogenetic tree was established,physiological and biochemical indexes were determined,and drug sensitivity indexes were determined.It was found that the characteristics of the isolated BRC-CXG2 strain were consistent with the characteristics of Serratia,but different from those of the same genus.In addition,BRC-CXG2 had certain insecticidal activity against larva of M.alternatus,but was relatively safe for mammals.For further in-depth study of Serratia were isolated by the BRCCXG2 insecticidal mechanism as well as the development of the strain provide genetic information,for Serratia BRC-CXG2 for genome sequencing,and used the software to the whole genome sequencing data fine annotation,the joining together of the genome,gene functional annotation,comparative genomics and evolutionary relations among species,complete the circle diagram and promoter prediction.The results showed that the draft sequence of BRC-CXG2 genome was 5.7M in size and GC content was 59.57%.This sequence has been submitted to Gen Bank database(KT366770).In addition,it has been found that the genome of BRC-CXG2 has a significant collinearity relationship with the genome of S.marcuscens ASM33642V1.For exploring new insecticidal gene in the genome,this study of chitinase chi A1t1 gene cloning and bioinformatics analysis through bioinformatics analysis method combined with a variety of bioinformatics techniques and tools,and under the network database resource support,analyses the regional chi A1t1 genes across a cell membrane,signal peptide,study the expression of protein after physical and chemical properties,structural domain,and so on.It was found that the signal peptide of ChiA1t1 is a hydrophobic transmembrane region,and the protein is a secreted protein.Based on the results of the above experiments,it is helpful to promote the study of the activity and effectiveness of the BRC-CXG2 of Serratia,to provide the possibility for the future use of Serratia to prevent and control the Monochamus alternatus Hope,and to provide a theoretical basis for the development and application of new microbial pesticide engineering bacteria.