Location: Crop Protection and Management Research
Title: Reactive oxygen species and their possible role in defense signaling in maize-Aspergilus flavus interations Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2014
Publication Date: March 11, 2014
Citation: Fountain, J.C., Scully, B.T., Gold, S.E., Glenn, A.E., Kemerait, R.C., Guo, B. 2014. Reactive oxygen species and their possible role in defense signaling in maize-Aspergilus flavus interations [abstract]. Gerogia Association of Plant Pathologist. Technical Abstract: The colonization of maize by Aspergillus flavus and the contamination of kernel tissues with aflatoxins has been the subject of intensive research for >40 years. Several proteins have been identified as components of resistance against A. flavus. Many function in abiotic stress tolerance by preventing damage due to reactive oxygen species (ROS). Expression of the aflatoxin gene cluster in several Aspergillus spp. has also been shown to be stimulated by oxylipins and ROS. This suggests that ROS may function in cross-kingdom signaling between maize and A. flavus and may play a role in resistance. We are investigating the possible role of ROS in maize-A. flavus interactions, global defense regulation, and the possible role of aflatoxin as a form of antioxidant protecting the fungus from oxidative stress caused by hot/ dry environments. Preliminary data suggest that amending PDB or YES culture media with H2O2 enhances aflatoxin production in toxigenic A. flavus strains (3557, A9). H2O2 concentrations =50mM were lethal to both toxigenic and atoxigenic strains. There was no difference in biomass between the atoxigenic (A1) and toxigenic (A9) strains tested in cultures with =10mM H2O2. However, strain A9 grew significantly better at 25mM H2O2, suggesting that aflatoxin production may provide protection to A. flavus against environmental ROS possibly derived from abiotic stress or host defense responses. Further in vivo study will be conducted in corn and peanuts.