Discovery of novel microorganisms involved in ergot alkaloid detoxification: An approach

Abstract

Fescue toxicosis and ergot alkaloids are estimated by the United States Department of Agriculture (USDA) to cost the U.S. ranchers $860 million per year. The endophyte fungi Neotyphodium coenophialum is present in tall fescue (Festuca arundinacea). This fungus produces toxic alkaloids (principally ergovaline) that cause deleterious effects in cattle and other livestock when infected grasses are eaten. Previous studies in sheep and cattle have yielded no culturable microbes able to detoxify the ergot molecules, leading to the search for novel sources of anaerobic organisms capable of degrading ergot alkaloids. Anaerobic incubation of earthworm (Eisenea fetida) homogenate with pure ergovaline has exhibited a 60% decrease in ergovaline concentration. Digestive tracks were dissected from worms obtained from an endophyte-fed digester. Cloning and partial sequencing of bacterial 16S rDNA obtained from these samples revealed a diverse microbiota, including bacteria sequences which classified into the phyla Bacteroidetes, Firmicutes, Proteobacteria, and Planktomycetes. Future work is focused on refining our understanding of the contribution towards possible ergot alkaloids detoxification made by the bacteria of the worm-gut microbiota. Keywords: ergovaline, microbial degradation, endophyte, tall fescue, perennial ryegrass, Eisenea fetida