Diversity, Roles, and Biotechnological Applications of Symbiotic Microorganisms in the Gut of Termite.

Termites are global pests and can cause serious damage to buildings, crops, and plantation forests. The symbiotic intestinal flora plays an important role in the digestion of cellulose and nitrogen in the life of termites. Termites and their symbiotic microbes in the gut form a synergistic system. These organism work together to digest lignocellulose to make the termites grow on nitrogen deficient food. In this paper, the diversity of symbiotic microorganisms in the gut of termites, including protozoan, spirochetes, actinomycetes, fungus and bacteria, and their role in the digestion of lignocellulose and also the biotechnological applications of these symbiotic microorganisms are discussed. The high efficiency lignocellulose degradation systems of symbiotic microbes in termite gut not only provided a new way of biological energy development, but also has immense prospect in the application of cellulase enzymes. In addition, the study on the symbiotic microorganisms in the gut of termites will also provide a new method for the biological control of termites by the endophytic bacteria in the gut of termites.

Molecular and Morphological Diversity of the Oxymonad Genera Monocercomonoides and Blattamonas gen. nov.

Oxymonads are a group of flagellates living as gut symbionts of insects or vertebrates. They have several unique features, one of them being the absence of mitochondria. Diversity of this group is seriously understudied, which is particularly true for small species from the family Polymastigidae. We isolated 34 strains of oxymonads with Polymastigidae-like morphology from 24 host species and unused cesspits and sequenced the SSU rRNA gene. Our strains formed two clades in the phylogenetic tree with Streblomastix strix branching between them. This topology was also supported by a three-gene phylogenetic analysis. Despite considerable genetic differences between the clades, light and electron microscopy revealed only subtle differences. The larger clade is considered genus Monocercomonoides and the isolates belonging here were classified into three new species (including the first potentially free-living species), two previously described species, and three unclassified lineages. The smaller clade, here described as Blattamonas gen. nov., consists of three newly described species. Concomitantly with the description of Blattamonas, we elevate the Monocercomonoides subgenus Brachymonas to the genus level. Our study shows that, despite their conserved morphology, the molecular diversity of Polymastigidae-like oxymonads is broad and represents a substantial part of the diversity of oxymonads.