Yeast diversity and screening for killer-toxin phenotypes in the Apterostigma ant fungiculture

• Grant number: 24/16911-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2025
• End date: December 31, 2026
• Field of knowledge: Biological Sciences - Microbiology - Biology and Physiology of Microorganisms
• Principal Investigator: André Rodrigues
• Grantee: Ana Raquel Martinez Castro
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Associated research grant: 19/03746-0 - Collaborative research: Dimensions US-São Paulo: integrating phylogeny, genetics, and chemical ecology to unravel the tangled bank of the multipartite fungus-farming ant symbiosis, AP.BTA.TEM

Abstract

Understanding the biological connections among individuals, both within and between species, is crucial for comprehending ecological interactions. The obligatory mutualism between fungus-growing ants (the attines) and their basidiomycete fungus is a characteristic example, where ants provide care and dispersal, and the fungus serves as their main food source. Attine ants have practiced fungiculture for 55-65 million years, cultivating various fungi in the tribe Leucocoprinae (family Agaricaceae) in addition to others outside this tribe. This is the case with Apterostigma ants, which cultivate Myrmecopterula velohortorum and Myrmecopterula nudihortorum (cultivars belonging to the family Pterulaceae), forming two distinct fungus garden types: with a mycelium cover (veiled) and without this cover (unveiled), respectively. Attine ants also host a diverse range of microorganisms in their gardens, including yeasts, which play vital ecological roles by inhibiting harmful fungi, breaking down plant substrates, and detoxifying compounds. Environmental factors and ant behaviors significantly impact yeast diversity in gardens of higher attines, highlighting the need for further research on lesser-studied lower attine ants like those in the genus Apterostigma. This proposal aims to investigate the diversity of yeasts in Apterostigma colonies by culture-dependent methods, focusing on their interaction with the two types of ant fungal cultivars. We will also explore yeast killer phenotypes which produce toxins with potent antimicrobial activity, potentially revealing new interactions in this system or new applications for human welfare. We will collect 20 Apterostigma ant colonies (10 "veiled" and 10 "unveiled") in the Atlantic rain and Amazon forests. By studying these lesser-known ants, we seek to understand whether fungal cultivar types can determine yeast community composition in gardens. This study will enhance our understanding whether additional factors, beyond the currently claimed factors, also play a role in the structuring of garden yeast communities.