Terry Torres-Cruz, Graduate Student, Penn State
Fusarium is a genus of filamentous fungi associated with plant diseases of economic importance. Abundant fungal flower-like structures (pseudoflowers) were recently discovered on three species of yellow-eyed grasses (Xyris) in western Guyana. An unusual new species of Fusarium was associated with these pseudoflowers, that likely induces their formation. This is the first report linking a Fusarium species to the phenomenon of flower mimicry. Our study aims to 1) characterize the signs, symptoms, and incidence of this disease through field observations, 2) determine the main dispersal mechanism of the fungus using molecular methods and cultivation to detect F. xyrophilum on plant and soil samples, 3) evaluate the role of pseudoflower formation on insect attraction through comparisons of field observations and volatile production between flowers and pseudoflowers, 4) determine if changes in the fungal and bacterial microbiomes are associated with induction of pseudoflowers, and 5) determine the genes involved in production of pseudoflowers using RNA sequencing. Preliminary results suggest that pseudoflower production is the only visible sign on plants and that their production is only observed on three Xyris species (X. setigera, X. surinamensis y X. bicephala) in savannahs of Guyana. Although plants do not require insects for pollination, we have observed insects visiting flowers and pseudoflowers. The volatile patterns produced by flowers and pseudoflowers are similar. Other pseudoflower-inducing fungi have been described, yet connections between disease-induced traits, transmission, and vector attraction require further research. Our study helps elucidate these plant-insect-fungus interactions by providing understanding of their evolutionary ecology and transmission biology.