Attine ants are farmers, and they grow fungi as food. Pseudonocardia and Streptomyces bacteria are their farmers, producing metabolites that protect the crop from pathogens. Surprisingly, these metabolites do not have common structural properties across bacteria from different geographic locations, even though the ants share a common ancestor.
Now, researchers are reporting in ACS Central Science they have identified the first shared antifungal fertilizer among many of these bacteria across Brazil. The crane may at some point have medical applications.
Attine ants originated from a single species at one location in the Amazon 50 million years ago. They have evolved into 200 species that have spread their farming practices throughout South and Central America. In exchange for food, bacteria at these farms produce small molecules that keep pathogenic fungi such as Escovopsis in a check.
However, these molecules vary from region to region, suggesting a microbial history that is highly dispersed and largely confined for the bacteria. Monica T. Pupo, Jon Clardy and colleagues wanted to find out if antifungal bacterial metabolites were neglected with a wider circulation in prior studies.
In a study of bacteria from ant nests at several sites in Brazil, the team found that nearly two-thirds of Pseudonocardia Rays produced a strong antifungal agent, called attinimicin. This finding marked the first report of a specialized metabolite with a broad geographic distribution produced by associated bacteria.
Although this metabolite was safe for the fungal crop, it inhibited the growth of fungal parasites, however – unlike many antibiotics – just without iron. He was also effective in fighting a Candida albicans infection in mice, in contrast to clinically used azole-containing antifungal medications, makes it a potential drug candidate. The researchers discovered the structure of attinimicin and examined its evolutionary relationship to two similar bacterial peptides extracted Streptomyces – oxachelin A and cahuitamycin A. The results show that the related genes in both types of bacteria are descended from a common ancestor.
Source:
Chemical Society of America
Magazine Reference:
Fukuda, TTH, et al. (2021) Specific metabolites reveal a history of evolution and geographic distribution of multivariate symbiosis. ACS Central Science. doi.org/10.1021/acscentsci.0c00978.