Collaborative Research: Diversity and Evolution of Ectomycorrhizal Fungi of the Guineo-Congolian Rainforest

Purdue University, West Lafayette IN

Investigators

Abstract

Some fungi live in close symbiotic association with plants. These ectomycorrhizal fungi provide resources to the plant host, and in return, the plant provides nutrition to the fungi. The interactions of fungi and their hosts provide crucial ecosystem functions including the recycling of nutrients. While the critical roles that fungi play in the environment are well established, their importance in tropical systems is not well understood, and this is especially true for tropical Africa. This project in the Guineo-Congolian rainforest will provide the first thorough documentation of these fungi and plant relationships of tropical Africa using modern methods. The huge forest covering the Congo River basin is one of the last great tropical rainforests of the world. Current threats to the region include logging, mining, and climate change. This project will fill a major gap in our knowledge of the important symbiotic fungi of this ecosystem through expeditionary fieldwork in the undisturbed rainforests of Cameroon. This project is potentially transformative in that if the fungi associated with closely related host plants of Africa and South America are shown to have a common ancient origin, such results would fundamentally impact understanding of the evolution, global biogeography, and local adaptation of ectomycorrhizal symbioses. Additionally, application of new DNA sequencing methods will develop entirely new, phylogenetically informative data that will transform the field. It is estimated that over 100 fungi will be discovered that are new to science. Recognition of these species will greatly inform broader research areas. Key features of the project include student training, internet-based information sharing, and public outreach. By combining traditional specimen-based sampling with high throughput DNA sequencing, this project will provide the most complete diversity data to date on ectomycorrhizal fungi of Afrotropical forests. Additionally, it will enable comparison of intercontinental tropical ectomycorrhizal fungal communities in corresponding ecosystems. The research will enhance understanding of fungal biogeography in the Gondwana-derived Afrotropical and Neotropical Guiana Shield regions. Survey plots identical to those used for surveys in the Guiana Shield of South America will be established in the Dja Biosphere Reserve and Korup National Park Cameroon and ectomycorrhizal fungi will be sampled using morphological and molecular methods over multiple years. Replication of sample design allows for direct comparisons between Africa and South America, allowing for robust biogeographic analyses to determine the evolutionary histories of ectomycorrhizal taxa in a global context.