|Perkins Veazie, Penelope|
Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: 1/15/2004
Publication Date: 12/1/2004
Citation: Bushnell, W.R., Seeland, T.M., Perkins Veazie, P.M., Krueger, D.E., Collins, J.K., Russo, V.M. 2004. The Effects of Deoxynivalenol on Barley Leaf Tissues. American Phytopathological Society Press. p. 270-284.
Technical Abstract: Deoxynivalenol (DON), a mycotoxin produced in barley and wheat head blight by Fusarium graminearum, was applied to detached barley leaves to learn what physiological changes were produced by the toxin. In trials with treated tissues incubated in light, DON at high concentrations (60-200ppm) caused loss of carotenoid and chlorophyll pigments from chloroplasts within 4 days, turning tissues white. Loss of these pigments was much slower when treated leaves were incubated in darkness. However, electrolytes were lost from treated leaves in both light and dark, indicating that treated cells degenerated whether in light or dark. Calcium ions (applied as 0.01 M calcium nitrate) greatly enhanced responses to DON so that 10-30ppm DON caused loss of nearly all chloroplast pigments in 3 days as measured spectrophotometrically. The plasmalemma of treated cells lost functional integrity as determined by increased uptake of Evans blue. Transmission electron microscopy showed sequential degenerative changes in cellular ultrastructure of the tonoplast (allowing cytoplasm to disperse into the vacuole of the cell), of mitochondria, of chloroplast grana, and of the plasmalemma. The results indicate that DON has a major role in the degenerative changes leading to cell death in Fusarium head blight. Furthermore, the effects of DON had some of the known characteristics of programmed cell death in plants, a finding in need of further investigation.