|Perkins Veazie, Penelope|
|SEELAND, TINA - University Of Minnesota|
Submitted to: Biochemistry and Cell Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2009
Publication Date: 1/31/2010
Citation: Bushnell, W.R., Perkins Veazie, P.M., Russo, V.M., Collins, J.K., Seeland, T.M. 2010. Effects of Deoxynivalenol on Content of Chloroplast Pigments in Barley Leaf Tissues. Biochemistry and Cell Biology. 100(1):33-41.
Interpretive Summary: Effects of deoxynivalenol on barley leaf tissues were investigated by stripping epidermis from abaxial surfaces of leaf segments 1-1.2 cm long and floating them with exposed mesophyll in contact with aqueous DON solutions. For leaf segments treated in light, DON at 30-90 ppm turned portions of some segments white after 48-96 hr of treatment, while remaining portions remained green. Untreated segments slowly became chlorotic. In the dark, no tissues turned white as treated segments retained green pigment. Ca(NO3)2 or CaCl2 greatly increased the effects of DON. In light, DON at 10-30 ppm combined with 10 mM Ca(NO3)2 turned most treated tissue white within 48 hr. These tissues lost chlorophyll a and b as well as carotenoid pigments. In dark, DON at 10-30 ppm with Ca(NO3)2 kept tissues fully green. However, in both light and dark, tissues began to take up Evans blue after 12-18 hr of treatment and to lose electrolytes by 24 hr, indicating loss of semipermeability of the plasmalemma in DON-treated cells. The results show that DON injured tissues by 12-24 hr, and that loss of chloroplast pigments was a secondary effect, dependent on light.
Technical Abstract: Fusarium head blight (scab) has been a devastating disease of wheat and barley in recent years across grain growing areas from Minnesota and the Dakotas to the Carolinas. The fungal pathogen causing the disease (Fusarium graminearum) produces a toxin, deoxynivalenol (DON) that can be toxic when infected grain is used as animal feed. DON also limits use of grain for human food. DON is suspected to play a role in development of Fusarium head blight by promoting infection and spread in the head. The research described here is the first major investigation of how DON affects plant tissues. We found that green barley leaf tissues turn white within 2-4 days when treated with DON. The white tissues lost all chlorophyll (green) and carotenoid ( yellow) pigments, which are essential for photosynthesis. DON also caused plant tissues to leak substances from cells, a sign that the toxin damaged the membranes that enclose each cell. By showing how DON injures plant cells, the results will be useful for scientists investigating development of Fusarium head blight toward the goal of breeding varieties resistant to this important disease.