Date of this Version
Van Roy, Z. (2019). Identifying Toxin-Producing Fungal Species and Relative Species Diversity in Plant Tissue. Undergraduate Honors Thesis. University of Nebraska-Lincoln.
Various fungal organisms both inhabit widely grown cereal crops and produce mycotoxins as a byproduct of their proliferation. In addition to causing disease in these crops, toxins in contaminated plant tissue have negative implications in livestock and human health by means of toxin persistence in ingested feed or food products. To determine the overall abundance of these toxin-producing fungal species in plant tissue relative to non-pathogenic species, fungal DNA from harvested Sorghum bicolor whole-plant tissue was extracted, ligated into cloning vectors, and transformed into E. coli. The resulting vectors were then extracted from mono- clonal colonies, sequenced, and contained fungal sequences identified through cross-referencing a genetic database. This analysis was performed on samples from two years (2014 and 2016), two tissue preparation styles (chopped and bagasse), and four sorghum cultivars (Wray, Rio, Dale, and M81E) to also determine if any identified species show preference for di↵erent grow- ing conditions. We found evidence for the presence of multiple known toxin-producing fungal species in our sorghum tissue samples as well as observed statistically significant segregation of at least one fungal species across each of the three variables tested (year, preparation method, and cultivar). This work has profound implications in explaining the natural fungal diversity found in western Nebraska agricultural fields as well as further elucidates the unique interac- tions between toxin-producing fungi and widely cultivated cereal crops. Lastly, these results serve as a basis for further research in limiting harm caused by toxins in agricultural products.