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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC CONTROL OF FUSARIUM MYCOTOXINS TO ENHANCE FOOD SAFETY

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: An Arabidopsis non-specific lipid transfer protein provides enhanced resistance to a trichothecene mycotoxin by reducing oxidative stress

Authors
item Mclaughlin, John -
item Bin-Umer, Mohamed -
item Widiez, Thomas -
item McCormick, Susan
item Tumer, Nilgun -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 5, 2013
Publication Date: December 5, 2013
Citation: McLaughlin, J.E., Bin-Umer, M.A., Widiez, T., McCormick, S.P., Tumer, N.E. 2013. An Arabidopsis non-specific lipid transfer protein provides enhanced resistance to a trichothecene mycotoxin by reducing oxidative stress [abstract]. U.S. Wheat Barley Scab Forum.

Technical Abstract: Fusarium head blight (FHB) caused by Fusarium graminearum, is one of the most important diseases of wheat and barley. Trichothecene mycotoxins, such as deoxynivalenol (DON), are virulence factors of F. graminearum and accumulate in the grain causing a serious threat to human and animal health. Current methods for control of FHB have had limited success in reducing disease levels and toxin contamination of small grains. We screened an activation tagged Arabidopsis population for resistance to trichothecin (Tcin) and identified two closely linked nonspecific lipid transfer protein (nsLTP) genes, which were overexpressed in a resistant line. Treatment of wild type Col-0 with DON or Tcin induced reactive oxygen species (ROS) in leaves as measured by a quantitative Amplex Red assay. Confocal microscopy with 2’,7’-dichlorofluorescin diacetate (H2DCF-DA) was used to examine the effect of Tcin on ROS generation. ROS generation was observed in the cell wall/apoplast region of the leaves and clearly colocalized with the chloroplast, suggesting that potential damage to the chloroplast is a source of Tcin-induced ROS in the cell. Treatment of Arabidopsis leaves with 2 mM vitamin C, PABA, or vitamin E protected against the toxic effects of Tcin in detached leaf assays, providing further evidence that ROS plays a role in Tcin mediated tissue damage. In addition, we found a significant effect of light on Tcin toxicity. Incubation of detached leaves in the dark with Tcin provided the greatest protection from chlorosis and tissue death relative to 16 h light/8 h dark treatments. Previously we have shown that Arabidopsis lines overexpressing two different nsLTPs showed reduction in chlorosis and cell death after Tcin treatment and were able to germinate and form roots on medium containing Tcin. Overexpression of nsLTPs in Arabidopsis and yeast reduced oxidative stress upon trichothecene exposure. AtLTP overexpressing lines had significantly attenuated ROS levels upon exposure to Tcin relative to the non-transgenic control. These results demonstrate that ROS production, a component of which is derived from the chloroplast, contributes to the toxicity of trichothecenes in plants and overexpression of an nsLTP enhanced trichothecene resistance, possibly by reducing oxidative stress.

Last Modified: 12/19/2014
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