Microbial Diversity Of The Infrabuccal Pocket In Camponotus Japonicus Mayr

Ants are the most abundant taxa for animal species and quantity in the terrestrial ecosystem,and also the highly evolved social insects.Most ants are usually omnivorous,they can feed on not only liquid food such as honey,tree sap and homopteran honeydew,but also solid food such as seeds of plants,other insects and corpses of small animals.However,the special pouch-like filtration device,locates in preoral cavity of ants-infrabuccal pocket,could filtered the solid food particles and then discharged them from the preoral cavity.Hence,only liquid food could enter and temporarily stored in the crop of workers,and then they will be shared with the other workers,larvae and queen later through feedback(trophallaxis).The filtration mechanism prevent alimentary tract from blocking.While previous studies showed some microorganisms in the infrabuccal pocket,for the distribution and function of these microorganisms is also lack of extensive research.In order to understand the composition of microbes in the infrabuccal pocket and reveal the potential role they may play in food utilization and immune protection,we analyzed the composition and diversity of microbes in the infrabuccal pocket of Camponotus japonicus Mayr,and then preliminarily determined the antibacterial activity of actinomycetes.The main results are as follows:1.The microbes were isolated using culture-dependent method and identified with DNA sequence analysis.The results showed that:(1)10 actinobacterial strains were isolated from the infrabuccal pocket,among them,5 strains belonged to Streptomyce and their average isolation frequencies were 73% to 96.7%;7 bacterial strains were isolated and 4 of them were Bacillus,and the average isolation frequency of the N-B1 and N-B4 were both above 70%;Three fungal strains were isolated,and the isolation frequency of P-F1(Wickerhamiella)was up to 96.7%.(2)Compared with the cuticle and digestive tract,more microbes can be found in the content of infrabuccal pocket,especially actinomycetes.2.The bacteria diversity in the infrabuccal pocket and other tissues were investigated using HiSeq high-throughput sequencing method,the results showed that:(1)The dominant bacterial groups in the infrabuccal pocket mainly belonged to Proteobacteria,Firmicutes and Actinobacteria,while in the crop and midgut mainly included Proteobacteria and Firmicutes.(2)The dominant genera in infrabuccal pocket were Fructobacillus,Bacterium,Pseudomonas,Acinetobacter and Sphingtomonas,respectively.(3)The bacterial abundance and diversity in the infrabuccal pocket and crop were higher than those in midgut.3.The diversity of fungi in the infrabuccal pocket and other tissues were investigated using HiSeq high-throughput sequencing method,the results showed that:(1)Except for the midgut,the distribution of fungal strains in all other samples were similar to those in the infrabuccal pocket samples.Alternaria and Cladosporium were the absolute dominant genus in the infrabuccal pocket,while Gibberella was dominant in the midgut;(2)The Wickerhamiella was not only distributed in the infrabuccal pocket,but also crop and midgut;(3)The abundance and diversity of the fungi in the infrabuccal pocket were lower than the others.4.The antimicrobial activity of the actinomycetes isolated from the infrabuccal pocket were screened,the results showed that:(1)All 10 actinomycetes strains had different level antibacterial activity to 8 strains of tree pathogenic fungi.4 strains(G-A3,Streptomyces,G-A5 Streptomyces,G-A6 Tsukamurella,and G-A7 Tsukamurella)exhibited inhibitory activity for all the 8 pathogenic fungi;(2)The antibacterial rate of 6 actinomycetes strains(G-A1 Streptomyces、G-A2 Streptomyces、G-A3、G-A5、G-A6、G-A7)were more than 40%on one or more pathogenic fungi,showing strong inhibitory activity.