Print PagePlant products and their associated fungi are transported all over the world via the industrial food system. The globalization of food allows us to investigate whether fungi associated with agricultural commodities show cosmopolitan distribution or have a restricted geographic range due to dispersal limitation or mode of production/transportation. We are developing the coffee trade as a model system for testing the global distribution of crop-associated contaminant fungi and the impact of global transport of food. Through coffee we explore how modes of production can alter community structure and gene flow. Specifically, we are testing whether different methods of agricultural production lead to the assembly of distinct fungal communities on coffee, including mycotoxigenic fungi. Using both culture-dependent and culture-independent methods, we have assessed fungal communities of conventional and organic green coffee beans from multiple geographic regions. Culture-dependent methods involved plating 200 surface-sterilized beans per lot on Dichloran-glycerol 18 and Malt Extract Antibiotic agar media. Fungi were isolated into pure culture and identified by sequencing of the ITS ribosomal RNA. Culture-independent methods of assessing fungal community assemblage involved extracting DNA from whole green beans from 20 conventional and organic bean samples from different geographic regions and the use of fungal specific universal primers (ITS1-F and ITS4) to amplify the fungal DNA found in the beans.
Results/Conclusions
Results from culture-dependent and culture-independent studies show that distinct fungal communities form on the same substrate of different geographic locations. Fungal species diversity appears to be affected by method of agricultural production, and communities of different geographic regions are composed of different species, suggesting that although food fungi may be cosmopolitan, they may not be ubiquitous.
