Phylogenetic Diversity of Bacterial Symbionts in the Guts of Wood-Feeding Termites

Abstract

The diversity of bacterial symbionts in termite guts was investigated by 16S rDNA analyses and terminal restriction fragment length polymorphism (T-RFLP). Bacterial DNAs from guts of two woodfeeding termites, consisting of a lower termite, Reticulitermes speratus and a higher termite, Microcerotermes sp. were extracted and 16S rRNA genes were amplified by PCR using several sets of bacterial specific primers. PCR products were then cloned, sequenced and analyzed for T-RFLP. Two thousands one hundred and eighty four clones from R. speratus and 288 clones from Microcerotermes sp. were analyzed and sorted into 320 and 141 phylotypes, respectively. Most of them were spirochetes, which were found more than half of the sequenced clones and detected T-RFs, while the second-dominant groups were Clostridia and Bacteroides. Interestingly, over 90% of the phylotypes obtained in this study were found at the first time, and several termite-specific lineages, including a novel bacterial division, Termite Group I, which are as-yet unculturable bacteria, were revealed. These results indicated that termite gut is really a great reservoir of new bacterial species, and that the termite gut is still a new frontier to microbiologists.