Submitted to: Journal of Microbiology and Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/30/2012
Publication Date: 6/28/2012
Citation: Choi, Y., Butchko, R.A., Shim, W. 2012. Proteomic comparison of Gibberella moniliformis in limited-nitrogen (fumonisin-inducing) and excess-nitrogen (fumonisin-repressing) conditions. Journal of Microbiology and Biotechnology. 22(6):780-787. Interpretive Summary: The fungus Gibberella moniliformis can cause the contamination of corn kernels with toxins called fumonisins. These toxins pose a threat to humans and livestock alike and are a food safety concern. Nitrogen is a nutrient required for both the fungus and the plant. Limiting nitrogen induces the production of toxin while excess nitrogen negatively affects the ability of the fungus to produce toxin. In this study, we employed a proteomics approach to identify three novel genes that appeared to play an important role in fumonisin biosynthesis under nitrogen stress. These results provide important insights into the regulation of fumonsin production and the development of novel strategies for reducing or eliminating toxin contamination of food and feed.
Technical Abstract: The maize pathogen Gibberella moniliformis produces fumonisins, a group of mycotoxins associated with several disorders in animals and humans including cancer. The current focus of our research is to understand the regulatory mechanisms involved in fumonisin biosynthesis. In this study, we employed a proteomics approach to identify novel genes involved in the fumonisin biosynthesis under nitrogen stress. The combination of genome sequence, mutant strains, EST database, microarrays, and proteomics offers an opportunity to advance our understanding of this process. We investigated the response of the G. moniliformis proteome in limited nitrogen (N0, fumonisin-inducing) and excess nitrogen (N+, fumonisin-repressing) conditions by one- and two-dimensional electrophoresis. We selected 11 differentially-expressed proteins, six from limited nitrogen conditions and five from excess nitrogen conditions, and determined the sequences by peptide mass fingerprinting and MS/MS spectrophotometry. Subsequently, we identified the EST sequences corresponding to the proteins and studied their expression profiles in different culture conditions. Through the comparative analysis of gene and protein expression data, we identified three candidate genes for functional analysis and our results provided valuable clues regarding the regulatory mechanisms of fumonisin biosynthesis.