gut microbiota of wild-living blackworm (V1-3 region, 454 pyrosequencing). gut microbiota of wild-living blackworm (V1-3 region, 454 pyrosequencing)

We analyzed the bacterial communities in the gut of blackworm Lumbriculus variegatus by pyrosequencing of extracted intestinal metagenomic DNA. The blackworms were collected from two sampling sites (GP7 and GP8) at a stream which have slightly different environmental condition such as sun irradiation and riparian vegetation. Site GP7 was covered by riparian vegetation whereas site GP8 was exposure to sunlight. After quality filtered sequence counts of 16S rRNA sequencing, we got 7785 reads from total six samples of two sites. The bacterial community in the gut of blackworm from two different environmental habitats was composed of the seventeen phyla with dissimilar proportions. Interestingly, Phylum Proteobacteria is a major portion with 62% and 42% of site GP7 and site GP8, respectively, whereas remaining phyla were revealed below 10% portions in both sites. Two different sampling sites displayed differences of microbiota community composition as well as their genetic categories in terms of biochemical pathway. Community indices such as species richness, Shannon diversity index, and evenness were higher at site GP7 than at GP8. Meanwhile, abundance of strains with chloroplast was significantly higher at site GP8 than at GP7. Site GP7 was related mostly with genes for membrane transport and carbohydrate metabolism, whereas site GP8 was with genes for photosynthesis and energy metabolism, reflecting differences of food resources of blackworms. Finally, therefore, our results present that the habitat condition including food resources and physicochemical environment determine the gut microflora of blackworms.