Bacterial diversity in Guangxi buffalo rumen
广西水牛瘤胃中的细菌多样性

Objective] To analyze the diversity of bacterial community in Guangxi buffalo rumen and to identify the possible cellulolytic bacterial group. Methods] Metagenomic DNAs were isolated directly from a buffalo rumen and its enriched culture, and were used as PCR templates to amplify 16S rRNA genes. Two libraries carrying 16S rRNA genes of bacteria in the two samples were constructed. The bacterial community composition was revealed by the constructed phylogenetic tree of known sequences and the sequences randomly selected from the libraries. Results] We found that both samples contained low G+C Gram-positive bacteria (LGCGPB) and Cytophaga-Flexibacter-Bacteroides (CFB) phyla as the majorities, and Spirochaetes as the minorities. LGCGPB accounts for 56.66% and 73.33% of the bacterial communities in buffalo rumen and its enriched culture. We detected Fibrobacteres in the rumen sample (3.33%) but not in the enriched sample. Furthermore, we found Proteobacteria as a major component in the enrichment (13.33%) but not in the rumen sample. Clone R46 was not clustered into any known phyla and might belong to a novel taxonomic group. Conclusion] The LGCGPB and Proteobacteria may play important roles in the hydrolysis of cellulose in buffalo rumen. The bacterial composition in the rumen of buffalo is quite similar to those in the rumen of yak, cattle and sheep.