|YANG, LIMING - University Of Georgia
|FOUNTAIN, JAKE - University Of Georgia
|JI, PINGSHENG - University Of Georgia
|KEMERAIT, ROBERT - University Of Georgia
|LEE, ROBERT - University Of Georgia
Submitted to: International Conference on Advances in Arachis through Genomics and Biotechnology
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2015
Publication Date: 11/4/2015
Citation: Yang, L., Fountain, J.C., Ni, X., Ji, P., Scully, B.T., Kemerait, R.C., Lee, R.D., Guo, B. 2015. Redox systems are a potential link between drought stress susceptibility and the exacerbation of aflatoxin contamination in crops [abstract]. 8th International Conference on Advances in Arachis through Genomics and Biotechnology.
Technical Abstract: Drought stress aggravates Aspergillus flavus infection and aflatoxin contamination in oilseed crops such as peanut and maize. Reactive oxygen species (ROS) are produced in plants in response to abiotic and biotic stresses as a means of defense. In the host plant-A. flavus interaction under drought conditions, the roles of ROS production remain unclear. In order to investigate the possible reasons of drought induced aflatoxin contamination, several maize lines with differential resistance to drought and aflatoxin contamination were subjected to drought treatment. Proteomic and enzymatic activity analyses demonstrated that drought tolerance was associated with different responsive patterns in redox homeostasis and ROS metabolism processes in developing kernels and seedling leaves. Drought stress triggered more rapid increases in the expression of ROS-scavenging enzymes such as superoxide dismutase, glutathione S-transferase, and antioxidant enzymes such as thioredoxin and peroxiredoxin in sensitive lines in comparison to tolerant lines. In addition, the potential roles of host derived-ROS in stimulating aflatoxin production were explored using a modified kernel screening assay. Kernels were with and without pre-incubation in high humidity for 3 days to induce differential ROS accumulation in kernel tissues followed by A. flavus inoculation. Pre-incubation resulted in reduced aflatoxin contamination with the drought tolerant line exhibiting greater aflatoxin resistance. Given that hydrogen peroxide (H2O2) have been shown to stimulate the production of aflatoxin in A. flavus in vitro, the above results imply that drought-induced ROS increases in crops may act as important inducers of aflatoxin production in A. flavus. Continuing research will further examine the role of these redox systems in peanut and explore the crosstalk signaling pathways between these crops and the fungus.