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United States Department of Agriculture

Agricultural Research Service

Research Project: PHYSIOLOGICAL AND MOLECULAR SIGNALING IN VIROID AND BACTERIAL DISEASE

Location: Molecular Plant Pathology

Title: Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

Authors
item Averyanov, A -
item Zakharenkova, T -
item Lapikova, V -
item Pasechnik, T -
item Gaivoronskaya, L -
item Baker, Con

Submitted to: Russian Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2013
Publication Date: October 15, 2013
Citation: Averyanov, A.A., Zakharenkova, T.S., Lapikova, V.P., Pasechnik, T.D., Gaivoronskaya, L.M., Baker, C.J. 2013. Exogenous superoxide dismutase may lose its antidotal ability on rice leaves. Russian Journal of Plant Physiology. 60:270-278.

Interpretive Summary: Fungal diseases of crops cause major losses for farmers each year. Many of these diseases start by the germination of the fungal spore on the leaf surface. By learning to disrupt critical mechanisms that are involved in spore germination we could reduce the amount of disease. This study demonstrates that plants are able to block fungal antioxidant mechanisms that protect fungal spores from reactive oxygen released by the plant. This occurs prior to the spore penetrating the plant and therefore prevents disease. This information will be of use to plant scientists who are devising new strategies to improve disease resistance in plants.

Technical Abstract: Leaf diffusates of the resistant rice cultivars suppressed spore germination of blast fungus (Magnaporthe grisea). Bovine Cu-Zn superoxide dismutase (SOD) added to the diffusate abolished its toxicity. However, the enzyme added to the inoculum did not affect the toxicity of the diffusate. Even the second SOD portion added to the diffusate was ineffective. As well, the enzyme exposed to leaves could not protect from artificially-generated superoxide. Presumably, SOD contacting with leaves induced an efflux of compound(s) inhibiting both portions of the enzyme. Evidence was obtained suggesting that neither enzymatic protein nor zinc of coenzyme but copper might be the inducer. Comparison of rice leaves and callus culture together with effects of exogenous salicylic acid suggest that this compound may be the inhibitor liberating from leaves. It is not excluded that rice plants are capable of inactivation of pathogens’ antioxidant enzymes, and that this ability favors disease resistance.

Last Modified: 12/27/2014
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