Polyols and volatile compounds in ant fungus gardens: ecology, evolution and biotechnological applications

Abstract

Ants from the Attina subtribe (Formicidae: Myrmicinae), the attinas, are distributed in the American continent, with most species in South America. They occur in 15 genera and more than 250 species, which depend for their nutrition, on mutualistic fungi. that digest a variety of substrates in the "fungus gardens" in their nests. We manipulate the garden of the Atta bisphaerica cutter, which degrades monocotyledons into monosaccharides and polyols, and we are able to reproduce the conversion of plant biomass into mannitol and arabitol, two products of the highest economic value. In addition to the cutters, which digest fresh leaves, there are four other groups of attinas ants specialized in digesting other types of biomass: vegetable seeds, insect carcasses, insect feces, leaves and withered flowers that fall from plants, monocots, dicots. The enzymes and products generated in these processes remain unknown to Science and unexplored by Biotechnology. It is not known whether these four specialists also generate polyols or even another product of biotechnological interest. Polyols can be stored in large quantities without causing relevant osmotic changes, they are not easily assimilated by invading microorganisms, they can stabilize digestive exoenzymes in gardens and are nutritional sources for ants. Advantages like these make polyols production an important evolutionary innovation for mutualism between ants and fungi, whose origin and evolution remain unknown. Additionally, polyols can represent an important means of chemical communication directing the preference of ants, which is a key phenomenon in the origin of mutualism. Seeking to test these hypotheses and answer those questions, the present postdoctoral project has the following objectives: (1) to determine the palatability of polyols to ants and the possible effects of these substances on the behavior of selection or refusal of fungi presented to them, as well as evolutionary implications in the choice of partner over the course of mutualism; (2) assess the behavioral responses of ants to different types of polyols; (3) to verify the presence of the innovation already characterized in cutters in the other four types of agriculture practiced by ants in the Attina subtribe; (4) identify other products of biomass bioconversion by attentive systems, seeking to inspire new biotechnological processes for the production of compounds with high market value and (5) to reveal aspects of the metabolic integration between ants and microorganisms. (AU)