Research Round Up
CAES researchers fight fungi, unlock genetic mysteries and study insect societies
Stories by Merritt Melancon
Working to understand the genetics of peanut disease resistance and yield, researchers led by scientists at the University of Georgia have uncovered the peanut’s complicated evolution.
Researchers working as part of the International Peanut Genome Initiative have previously pinpointed one of the peanut’s two wild ancestors and shown that the peanut is a living legacy of some of the earliest human agricultural societies in South America. Since then the team has mapped the entire peanut genome and identified the crop’s second wild ancestor and the novel mechanism by which the shy, seed-hoarding plant generated the diversity we see today.
Parallel work by a UGA team led by UGA Regents Professor Andrew Paterson resulted in the publication of a gold-standard peanut genome in which the work with peanut’s progenitors were expanded to include the genome of the modern cultivated tetraploid peanut. The tetraploid peanut and 52 additional types representing 12 species were sequenced with guidance from the diploids.
“Because of its complex genetic structure, sequencing peanut was only possible using very recent developments in sequencing technology. The result is of unprecedented quality, and provides a reference framework for breeding and improvement of the peanut crop, and a whole new set of insights into the extraordinary genetic structure of peanut,” said David Bertioli (pictured), Georgia Research Alliance and Georgia Seed Development Distinguished Investigator and peanut researcher at UGA.
University of Georgia mycologist Marin Brewer has been awarded close to $500,000 from the U.S. Department of Agriculture National Institute of Food and Agriculture to search for ways to detect antifungal resistance in a naturally occurring fungus and identify the factors that contribute to its resistance in agricultural environments.
Throughout the three-year study Brewer will focus on Aspergillus fumigatus, a fungus that is abundant in soil, compost and other organic debris. This fungus can cause serious lung infections in immunocompromised people and serious yield losses in crops like peanuts, corn, cotton and onions.
“Antifungal treatments are used to treat both plants and people, but fungal resistance to these treatments is developing in both the clinical and agricultural environments,” said Brewer, associate professor in the Department of Plant Pathology.
For people with compromised immune systems, fungal infections can be deadly, and medicines containing azole antifungal compounds are life-saving. Without treatment with azole antifungal compounds, or when the fungus resists treatment, the mortality rate is 88%, she said.
In most colonies, ants work in service of a single reproductive queen, but that’s not always the way ant societies function.
CAES researchers have found colonies of tropical fire ants, native to Florida and coastal Georgia, that thrive with multiple queens and in close proximity to single-queen colonies of the same species.
“The coexistence of two dramatically different social structures fascinated me,” said Kip Lacy (MS — Entomology, ’18), “I had to know more.”
Lacy, who is a graduate fellow at The Rockefeller University, worked with fire ant researchers Ken Ross and DeWayne Shoemaker (BSA — Entomology, ’89; PhD — Entomology, ’95) at the University of Tennessee to isolate and document multi-queen colonies.
Their work appeared in the April 2019 edition of Current Biology.
Lacy worked with colleagues at the USDA Agricultural Research Service in Gainesville, Florida, to help find and isolate the communities of native fire ants that still fill the shoulders and medians of Florida highways.
In these areas, they found that multi-queen “polygyne” colonies would be nestled right next to single-queen “monogyne” colonies of the same species. Nests with single queens were found as close as 5 feet away from nests with as many as 13 queens, Lacy said.