|Matsumoto Brower, Tracie|
Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2003
Publication Date: 10/2/2003
Citation: Narasimhan, M., Lee, H., Damsz, B., Singh, N., Ibeas, J., Matsumoto, T.K., Woloshuk, C., Bressan, R. 2003. Overexpression of a cell wall glycoprotein in fusarium oxysporum increases virulence and resistance to a plant pr-5 protein. Plant Journal 36 pg.390-400 Interpretive Summary: To control diseases in crop plants, identification of factors involved in the interaction of plants and pathogens are important in understanding how plants defend themselves again disease and how pathogens overcome the plant defense response. Here we show that Fusarium oxysporum, a plant pathogen, producing a yeast cell wall associated protein, PIR, is resistant to osmotin, a plant PR-5 (pathogenesis-related) protein produced under disease conditions. In addition, F. oxysporum producing PIR inoculated onto tobacco seedlings show more severe disease symptoms compared to tobacco seedlings inoculated with F. oxysporum not producing PIR. This evidence suggests that PIR protein is an important factor in determining pathogen susceptibility to proteins produced by the plant during pathogen attack, specifically osmotin.
Technical Abstract: Fusarium oxysporum f. sp. nicotianae is a causal agent for vascular wilt disease in tobacco. It is sensitive to osmotin, a tobacco pathogenesis-related protein (PR-5) that is implicated in plant defense against phytopathogenic fungi. We show that osmotin susceptibility of F. oxysporum f. sp. nicotianae was reduced by overexpression of the heterologous cell wall glycoprotein Saccharomyces cerevisiae protein containing inverted repeats (PIR2), a member of PIR family of fungal cell wall glycoproteins that protect S. cerevisiae from the toxic action of osmotin. S. cerevisiae PIR2 was targeted to the cell wall of F. oxysporum. Disease severity and fungal growth were increased in tobacco seedlings inoculated with F. oxysporum transformed with PIR2 compared to seedlings infected with untransformed F. oxysporum or that transformed with vector, although accumulation of transcript and protein of defense genes was similar. The results show that fungal cell wall components can increase resistance to plant defense proteins and affect virulence.