RAPID: The evolutionary relationships between Amauroderma fungi and the monocarpic tree genus Tachigali

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Tachigali is a genus of trees in the legume family distributed across the tropical forests of Central and South America. A unique feature of Tachigali is that many species are monocarpic: they flower only once in their lives and die shortly after reproducing. On Barro Colorado Island, Panama, Tachigali trees are also associated with the fungus Amauroderma. The fruiting bodies of this fungus only appear on the roots of Tachigali. They have never been found on other tree species. The specificity of this association suggests a parasitic or pathogenic relationship with Tachigali, but the mode and timing of infection remains unknown. Furthermore, while Amauroderma has been collected around other dead Tachigali species in South America, it is unclear whether this relationship is restricted to monocarpic Tachigali, or whether the tree and fungus have evolved together. This project takes advantage of a rare flowering event in Tachigali to collect and identify Amauroderma fungi and their associated hosts across multiple Amazonian and Central American sites. The project will provide new insights into the evolution and distribution of parasitic fungi that infect tropical forest trees, and training in mycology and bioinformatics for undergraduate students from the US and Latin America. Tachigali and Amauroderma collections will be made in mapped forest plots in five sites in Panama, French Guiana, Colombia, and Peru. To determine Amauroderma host range, fruiting bodies will be collected at each site by visiting live and dead Tachigali trees, noting the tree’s reproductive status and whether it is monocarpic. Metagenomic sequencing of tissue from seeds, seedlings, nonreproductive and flowering Tachigali trees will be used determine when Amauroderma infection occurs. Carbon and nitrogen stable isotope analysis of fruiting bodies will be used to compare the nutritional mode of Amauroderma to that of saprotrophic fungi associated with dead Tachigali trunks and roots. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.