The Bacterial Composition And Diversty In Intestinal Tarct Of Camponotus Japonicus Mayr

Camponotus is the second largest ant genus with nearly2000species known worldwide, which harbor the obligate intracellular endosymbiotic bacteria of Blochmannia genus, and then it becomes the mode group of ants in the gut bacteria research. Most researches focus on the distribution of Blochmannia, its relationship with the host ants, its functions and genome, etc. While studies show that insects harbor not only primary endosymbionts but also many other bacteria as secondary or facultative symbionts. In order to reveal the species composition and diversity of the gut bacteria of Camponotus japonicus, this study use both the culture-dependent method and the method of PCR-DGGE to estimate the gut bacterial diversity of C. japonicus and to clarify the similarity and difference among bacterial communities in the different gut regions (crop, midgut and hindgut) and different nests based on the previous study with16S rRNA-RFLP method. The results are as follows:1. Study of different parts of digestive tract in C. japonicus with conventional isolation and culture of microorganism method showed that there were5different bacterial strains. Sequence analysis showed that they belonged to Bacillus, Paenibacillus and Enterococcus in Firmicutes. Bacterial species existed in the midgut was relatively abundant, containing bacteria of Bacillus and Enterococcus, while there was only one genus in crop and hindgut, Bacillus sp. and Paenibacillus sp. respectively.2.12DNA bands were detected by denaturing gradient gel electrophoresis analysis of different parts of the digestive tract in C. japonicus, and sequence analysis showed that these bacteria belonged to the Proteobacteria and Firmicutes, including Pseudomonas sp., Candidatus Blochmannia, Fructobacillus sp. and an unknown species. All DGGE bands could be found in both midgut and hindgut while only two DGGE bands representative of Candidatus Blochmannia were not detected in the crop, the others were consistent with the midgut and hindgut.3. The worker guts of four clonies were checked by PCR-DGGE analysis, and34DGGE bands were found, and25sequences were obtained. The blasting results in the GenBank database showed that these bacteria belonged to Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria, including nine genera:Pseudomonas, Candidatus Blochmannia, Lactobacillus, Ewingella, Caulobacter, Burkholderia, Arthrobacter, Rothia, Erwinia and two unknown species.4. Study of gut bacteria in C. japonicus from different nests showed that bacterial diversity order from the biggest to the smallest was Haoping Temple, Taochuan town, Huangdui town, Yangling. Similarity coefficient between different nests did not exceed60%. The mostly similar nests were Taochuan town and Yangling,57.14%, and Camponotus japonicus in Haoping Temple and Yangling had the lowest similarity, only40%. After Comparing gut bacteria in the same region of C. japonicus worker ants in different nests, We found that bacteria in midgut had the most similarity, followed by hindgut and crop had the least similarity.5. Analysis of the species and amount of intestinal bacteria of C. japonicus in different nests showed that:Lactobacillus sp. were the dominant species in the digestive tract of C. japonicus collected from Huangdui town and they accounted for38.89%of the total number of intestinal bacteria, followed by bacteria of Pseudomonas and Candidatus Blochmannia,16.67%respectively. The dominant species in the digestive tract of C. japonicus collected from Haoping Temple were Pseudomonas sp. and Candidatus Blochmannia, each accounting for21.43%, followed by Arthrobacter sp., accounting for14.29%. The dominant species in the digestive tract of C. japonicus collected from Taochuan town were Pseudomonas sp. and Candidatus Blochmannia, each accounting for25%, followed by Lactobacillus sp., accounting for16.67%. The dominant species in the digestive tract of C. japonicus collected from Yangling were Pseudomonas sp. and Candidatus Blochmannia, both accounting for30%.These results suggest that intestinal bacteria of C. japonicus are relatively abundant. There are also other species such as Pseudomonas sp. and so on besides its symbiotic bacteria Candidatus Blochmannia. Both gut bacterial in different regions of C. japonicus and gut bacterial of C. japonicus in different nests have differences.