GROUP-SPECIFIC BACTERIAL DIVERSITY IN THE GUT OF FUNGUS-CULTIVATING TERMITES (MACROTERMES, ODONTOTERMES AND MICROTERMES SPECIES) FROM KENYA

Abstract

The mutualistic association between termites and their gut symbionts has continued to attract the curiosity of researchers over time. The aim of this study was to characterize group-specific bacterial community structure and diversity in the gut of three fungus cultivating termites Macrotermes michaelseni, Odontotermes and Microtermes species using PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Group-specific primers targeting members of the phyla Bacteroidetes, Firmicutes and Planctomycetes were used for PCR amplification of total DNA mixture extracted from termite guts. The PCR products were used as templates in a second PCR with nested bacteria DGGE-PCR primer pairs whose products were separated by DGGE. Representative DNA bands were excised from the gels, re-amplified, purified and sequenced. The sequences were blast analyzed and together with other reference sequences retrieved from the public GenBank were used to infer phylogenetic trees. All sets of sequences were deposited in the public GenBank. Results from the DGGE band patterns revealed a sharp contrast between the bacterial communities of M. michaelseni, Odontotermes and Microtermes species. This underlines the difference in group-specific bacterial diversity in the three termites. Phylogenetic analysis of the 16S rRNA gene sequences indicated that they were affiliated with the three phyla: Bacteroidetes, Firmicutes and Planctomycetes. Sequences (40%) affiliated with the phylum Planctomycetes were isolated and clustered with ‘Termite planctomycete cluster’, indicating that they are termite gut specific members. Sequences (89%) isolated were often affiliated with sequences obtained from other termites’ guts, demonstrating that a majority of the gut bacteria are autochthonous having mutualistic relationship with their hosts. Notably, the isolated sequences had less than 96% sequence similarity with the closest cultivated strains, indicating that the majority of termite gut bacterial lineages are still uncultured. The results will help better understand the bacterial symbionts-termites mutualistic associations.