Wild rice, Zizania palustris, can be an abundant grain crop of the northern Great Lakes region along slow moving waterways and lakes. Some populations of wild rice are known to be smuty, characterized by significant densities of an Ascomycete fungus infecting the grains, thereby reducing rice abundance and harvest. In an effort to better understand wild rice population dynamics and harvest opportunities, we are experimenting with the environmental parameters needed to awaken dormant sclerotia (resting structure) into their active life cycle. This research provided an exceptional opportunity for a dually enrolled high school-undergraduate student to learn the scientific method related to a significant research question her mentor’s research lab needed to better understand.
Smut sclerotia were collected from wild rice inflorescences in Lac Vieux Desert (LVD) on Michigan-Wisconsin border as well as from central Michigan (Upper Hamlin Lake). Purple sclerotia were collected from LVD and Hamlin Lake, along with an unidentified bright orange smut from Hamlin. The purposes of this research were to determine what conditions are needed to break dormancy on fungal sclerotia of Claviceps zizaniae, as well as identify the anatomical and taxonomic characteristics of the orange smut.
Results/Conclusions
The exclusion of light (aluminum foil) resulted in production of stipes (stalks) after about one month in water kept at 1 or at 25 degrees Celsius for Hamlin Lake sclerotia. The variable of light (14 hours of light from full spectrum florescent grow lights) appeared non-significant, as Hamlin Lake sclerotia placed in the light grew stipes at both temperatures for both orange and purple smuts. The first indications of dormancy break was observed after 22 days and characterized by growth of a single stipe out of the sclerotia. The fruiting body (cap and associated perithecia with asci) develops upon the stipe, and produces unique ascospores with a 100:1 ratio of length to width. This experiment has shown that sclerotia must be floating in/on water, but that the presence of light is not necessary, and that they make break dormancy in water just above freezing or at room temperature. Bacterial growth is abundant, and requires regular water changes, but can be overcome when this fungal pathogen is provided necessary growing conditions. This experiment should help researchers establish a simple protocol for growing Claviceps zizaniae in laboratory conditions to answer future research questions.
