Insights into the diversity of Amynthas morissi earthworm gut associated fungal community and their abilities to assimilate raw humus

The study of symbiotic relationship between species of microorganisms and invertebrates is one of the most important fields of soil microbial ecology. The vast diversity of microbes and animals suggests various links between them, including gut symbiosis. It is now well established that a healthy gut microbiota is largely responsible for overall health of the host. Fungi were isolated from the gut microbiota of the earthworm Amynthas morissi collected from the O horizons soil of Imphal valley, Manipur, Northeast India. Molecular phylogeny and internal transcribed spacer (ITS) gene sequence analysis demonstrated that the fungal strains belonged to four genera, Aspergillus, Penicillium, Myrothecium and Fusarium. Their potential to assimilate raw humus was tested based on secretion of extracellular enzymes. The abilities varied. Only Aspergillus tabacinus assimilated starch. Aspergillus terreus strongly assimilated pectin from citrus and birch xylan. A. tabacinus and Penicillium pinophilum assimilated protein. All the fungi assimilated cellulose. These results suggest a symbiotic association with multiple fungal species, with various carbon assimilation abilities. This would help the earthworm A. morissi to achieve efficient decomposition of complex macromolecular.