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Plant pathogens face different environmental clues depending on the stage of the infection cycle they are in. Fusarium graminearum infects small grain cereals producing trichothecenes type B (TB) that act as virulence factor in the interaction with the plant and have important food safety implications. This study addresses at the proteomic level the effect of an environmental stimulus (such as the presence of a polyamine like agmatine) possibly encountered by the fungus when it is already within the plant. Because biological diversity affects the proteome significantly, a multistrain (n=3) comparative approach was used to identify consistent effects caused on the fungus by the nitrogen source (agmatine or glutamic acid). Proteomics analyses were performed by the use of 2D-DIGE. Results showed that agmatine augmented TB production but not equally in all strains. The polyamine reshaped drastically the proteome of the fungus activating specific pathways linked to the translational control within the cell. Chromatin restructuring, ribosomal regulations, protein and mRNA processing enzymes were modulated by the agmatine stimulus as well as metabolic, structural and virulence-related proteins, suggesting the need to reshape specifically the fungal cell for TB production, a key step for the pathogen spread within the spike., Biological Significance: Induction of toxin synthesis by plant compounds plays a crucial role in toxin contamination of food and feed, in particular trichothecenes type B produced mainly by F. graminearum on wheat. This work describes the level of diversity of 3 strains facing 2 toxin inducing plant derived compounds. This knowledge is of use for the research community on toxigenic Fusarium strains in cereals for understanding the role of fungal diversity in toxin inducibility. This work also suggests that environmental clues that can be found within the plant during infection (like different nitrogen compounds) are crucial stimuli for reshaping the proteome profile and consequently the specialization profiling of the fungus, ultimately leading to very different toxin contamination levels in the plant., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Fusarium graminearum is widely studied as a model for toxin production among plant pathogenic fungi. A 2D DIGE reference map for the nivalenol-producing strain 453 was established. Based on a whole protein extract, all reproducible spots were systematically picked and analyzed by MALDI-TOF/TOF, leading to the identification of 1102 protein species. The obtained map contributes to the annotation of the genome by identifying previously nondescribed hypothetical proteins and will serve as a reference for future studies aiming at deciphering F. graminearum biology and chemotype diversity., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)