Isolation And Identification Of Potential Pathogenic Bacteria From Monochamus Alternatus Hope And Their Bacterial Diversity In Associated Habitats

Monochamus alternatus is the main vector of the pine wood nematode disease in China.So far,it is still the most important and efficient strategy for preventing spread of the disease to control M.alternatus.In this paper,the potential pathogenic bacteria of M.alternatus are identified by bacterial isolation and virulence test.The bacterial diversity of intestinal tracts and excrement of M.alternatus,and the phloem tissue,xylem tissue and rhizosphere soil of pines are systematically analyzed by OTU clustering and annotation.Hopefully,establish a new way using bacteria to control M.alternatus.The main results are as follows.1.A total of 37 strains of M.alternatus and their associated habitats are isolated,including 15 strains of endophytic bacteria from Pinus massoniana and 22 potential pathogens.The pathogenic bacteria CSLL101,which has high insecticidal activity against M.alternatus larvae,is screened by virulence identification.It's identified as Serratia entomophila and has a potentially high application value.2.Through modern molecular-biology and microbiology techniques,the diversity and potential association of bacteria in M.alternatus and their habitats are analyzed.It is suggested that bacteria of intestinal tracts and excrement are mainly distributed in Serratia and Enterobacter.The intrusion of M.alternatus is likely to lead to significant differences in the bacterial composition between healthy pines and dead pines.Bacteria of feeding pathway are the main source of intestinal bacteria of M.alternatus,3.Based on 16S rDNA amplified sub-sequencing technology,the potential relationship among P.massoniana,M.alternatus,and bacteria is speculated.The relevant bacteria colonize in P.massoniana through the soil and the surrounding environment or through wound caused by M.alternatus.Bacteria get into M.alternatus through feeding pathway,and participate in the metabolism and growth of insects,affecting bacteria composition of intestinal tracts on different growth stages.Therefore,screening bacteria that can not only colonize in pines without affecting their growth,but also cause disease or toxcity to M.alternatus,will provide a new and effective way to control M.alternatus.4.Based on OTU clustering,the relationship between Serratia and the life history of M.alternatus is systematically analyzed.It is found that Serratia mainly originate from the soil,they can colonize in phloem of P.massoniana.Then,they get into digestive system through the feeding process of the larvae of M.alternatus,and later,in the process of cellulase digestion,they are enriched in the intestines and form a reciprocal relationship with M.alternatus larvae.The association of Serratia and M.alternatus provides a potential pathway for the use of pine endophytic bacteria to control M.alternatus.