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Poster: Molecular & Cellular Plant-Microbe Interactions: Proteomics/Metabolomics/Genomics


Computational and functional analyses of MADS-box transcription factor-mediated regulation of fumonisin biosynthesis in Fusarium verticillioides
A. HILTON (1), A. Hilton (1), M. Kim (1), C. Ortiz (2), C. Woloshuk (3), B. Yoon (2), W. Shim (2) (1) Texas A&M University, U.S.A.; (2) Texas A&M University, U.S.A.; (3) Purdue University, U.S.A.

Fusarium verticillioides is an important maize pathogen, leading to Fumonisin B1 (FB1) in infested kernels. MADS-box transcription factors (TF) were found to modulate polyketide synthase (PKS) gene expression and FB1 production in F. verticillioides. With next-generation sequencing of F. verticillioides wild type and MADS-box TF mutant cultures, we used a suite of computational network-based tools, e.g. partial correlation, log-likelihood ratio matrix and seed-and-extend approach, to perform a system-oriented transcriptome analysis to predict downstream genetic subnetwork modules associated with FB1 production. Our aim was to identify and characterize system-level changes across correlated genes rather than simply focusing on individual gene expression. The resulting subnetwork modules are predicted to contain hub genes, which likely play a crucial regulatory role within functional modules. Two predicted subnetwork modules were analyzed in silico, and five putative hub genes were subjected to functional characterization. Deletion of RAS GTPase (FvRSR1) and methyltransferase (FvEFM3) led to a significant reduction in FB1 levels. A comparative qPCR was performed to investigate the impact of FvRsr1 and FvEfm3 on the expression of neighboring genes in two subnetworks, which did show significant changes. Collectively, these results support our prediction that FvRSR1 and FvEFM3 serve as a key hub gene in each subnetwork and regulate FB1 biosynthesis.