Authors: America Cox, Kendra Autumn , Bryn Dentinger
Mentors: Bryn Dentinger
Insitution: University of Utah
Neotropical ants of the Attini tribe evolved the innate ability to farm fungi. Agaricomycetidae contains two clades that are cultivated by ants: the lepiotaceous and pterulaceous cultivars. However, there are free-living relatives phylogenetically distributed throughout each cultivar clade. Comparison between the free-living relatives and attine system cultivars may identify the evolutionary differences caused by, or initially enabling, agricultural symbiosis. Our research compares free-living relatives and cultivars through genomic and metabolic analysis. Attines undertake significant cultivar maintenance through the regulation of pathogenic contamination of their fungal “gardens” as well as the provision of specific growth substrates, including insect frass. Noting the apparently specialized substrates cultivars receive from the ants, we conducted a pilot test for a growth media preference between a lepiotaceous cultivar, a pterulaceous cultivar, and a free-living pterulaceous relative. We placed the fungi on regular PDY media and PDY media infused with caterpillar frass, and the cultivars either changed structure or had improved growth on the frass-infused media. Following the pilot test, we will run metabolic assays on the cultivars and free-living relatives on different media types. This may indicate a media preference which gives further insight to the attine-fungal symbiotic relationship opposed to the fungal free-living relatives revealing pieces of the fungi’s evolutionary history. We performed DNA extraction, PCR testing, Sanger sequencing of the ITS region, and then whole genome sequencing on the cultivars and their free-living relatives. Sanger sequencing allowed us to build phylogenetic trees to examine the relationship between the free-living fungi and cultivars. The whole genome sequencing allowed us to use antiSMASH software to generate predicted secondary metabolite clusters in a fungi species that “escaped” cultivation, a cultivar, and a free-living relative. This preliminary data suggests a diversification of fungal secondary metabolites occurs after attine domestication. By looking at fungal metabolic and genomic data, we hope to gain insight into the fungi’s evolutionary history and agricultural symbiosis.