Data and code from: Pyrrocidines A and B demonstrate synergistic inhibition of fusarium verticillioides growth

Authors: Lofton, Lily; Read, Quentin; HAMILTON, HAILEY - University Of Georgia; Glenn, Anthony; Hawkins, Jaci; Mitchell, Trevor; Gold, Scott

Submitted to: Ag Data Commons
Publication Type: Database / Dataset
Publication Acceptance Date: 12/20/2024
Publication Date: 12/20/2024
Citation: Lofton, L., Read, Q.D., Hamilton, H.L., Glenn, A.E., Hawkins, J.A., Mitchell, T.R., Gold, S.E. 2024. Data and code from: Pyrrocidines A and B demonstrate synergistic inhibition of fusarium verticillioides growth. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/26239976.
DOI: https://doi.org/10.15482/USDA.ADC/26239976

Interpretive Summary: In corn (maize) kernels, a protective fungus called Sarocladium zeae produces potent chemical defenses to help its maize host fight off the toxic fungus Fusarium verticillioides. These compounds, called pyrrocidine A and B, each work in isolation to keep Fusarium from growing, but they work even better when they are combined together. In this study, we tested how much the two pyrrocidines, separately and together, prevent Fusarium growth. We also determined what genes in Fusarium help it to tolerate pyrrocidine by giving different doses of the two pyrrocidines to mutant Fusarium strains that each lacked a different gene. This dataset includes all the raw data and R statistical software code to reproduce the analyses in the paper, including statistical models, figures, and tables.

Technical Abstract: Fusarium verticillioides – a mycotoxigenic fungus and food safety threat – coinhabits maize kernels with Sarocladium zeae. This protective endophyte produces secondary metabolites of interest, pyrrocidines A and B, which inhibit the growth of F. verticillioides and specifically block fumonisin biosynthesis. Here, using pyrrocidine dose-response assays, we discovered a potent synergy between pyrrocidines A and B, where they functioned powerfully together to inhibit F. verticillioides growth. Further, results provided evidence that FvZBD1 confers partial tolerance to pyrrocidines, particularly pyrrocidine A, and that pyrrocidine functions through FvZBD1 to effectively eliminate fumonisin biosynthesis. Additionally, we showed that the FvABC3 (FVEG_11089) mutant, earlier described as hypersensitive to pyrrocidine, is particularly sensitive to pyrrocidine B. Thus, pyrrocidine A and B show different target specificity (FvZBD1 or FvABC3) and energistic action. The primary data analysis is a Bayesian generalized additive mixed model (GAMM) fit to the optical density data recorded at regular intervals from F. verticillioides strains grown in Bioscreen microtiter plates under different conditions, in a full-factorial design crossing strain (wild-type and two mutant strains) with multiple levels of pyrrocidine A and B concentration. The RMarkdown notebook imports the data, makes plots of the raw observations, fits the model to the data, and uses the posterior samples from the model to make predictions. Predictions are shown in graphical and tabular form, and evidence for effects is assessed using credible intervals of predictions, and Bayesian maximum a posteriori p-values (pMAP). A secondary analysis is presented of a dose-response assay: this is a frequentist linear model fit to a log-transformed concentration as a function of pyrrocidine type and concentration, followed by post-hoc comparisons within each pyrrocidine type. Again, results are presented in graphical and tabular form.