Proteomic identification of fungal induced protein hyperacetylation    
J. WALLEY (1), G. Song (1), M. McReynolds (1) (1) Iowa State University, U.S.A.

Pathogen infection triggers complex molecular perturbations within host cells that result in either resistance or susceptibility. Protein acetylation is an emerging post-translational modification that appears to play central roles during host-pathogen interactions. We are specifically investigating the role of protein acetylation in mediating the interplay between corn and the fungal pathogen Cochliobolus carbonum, the causal agent of Northern Leaf Spot. The main determinant of C. carbonum virulence is HC-toxin, which is a potent histone deacetylase inhibitor.  How HC-toxin mechanistically promotes virulence is not known, but it is hypothesized that HC-toxin promotes virulence via protein hyperacetylation. We have utilized global peptide mass spectrometry in order to identify host proteins altered in abundance and/or acetylation levels in corn plants treated with exogenous HC-toxin as well as HC-toxin deficient (Tox-) and producing (Tox+) strains of C. carbonum. These proteomic profiles revealed 44 sites that are hyperacetylated in response to both HC-toxin and Tox+ but not Tox- infection. The HC-toxin and Tox+ hyperacetylated proteins are enriched in transcriptional regulators whereas defense gene hyperacetylation is specifically enriched by Tox+. These findings combined with follow-up assays evaluating the functional impact of selected hyperacetylation sites suggest that HC-toxin transcriptionally triggers an inappropriate defense response to promote C. carbonum virulence.    

Abstract Number: P9-319
Session Type: Poster