Induction of pathogenesis-related proteins in germinating wheat seeds infected with Fusarium culmorum

The effect of Fusarium culmorum infection during the development of wheat s eedlings was investigated. The fungal infection reduced the germination of inoculated caryopses in comparison with that of control seedlings; symptoms were clearly evident on seedlings growth. At the molecular level, F. culmo rum infection caused the induction of a number of pathogenesis-related (PR) proteins. Two basic isoforms of beta-1,3-glucanase (PR2) and three basic i soforms of chitinase (PR3) were specifically induced upon infection, wherea s several acidic and neutral glucanase and chitinase isoforms accumulate co nstitutively. These findings suggest that PR2 and PR3 proteins, besides the ir involvement in plant defense, may play a role also in the normal process of seed germination. In addition, infection by F: culmorum caused the appe arance of wheatwins (PR4) and the increase of peroxidase (PR9) activity fro m the early stages of development of inoculated wheat seedlings. The coordi nated induction of several PR-proteins with different action mechanism are part of the defense strategy that the plant activates for limiting the fung al colonization. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved .