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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #323211
Title: Transcriptomic analysis reveal diverse responses to environmental oxidative stress in Aspergillus flavus

Author
item FOUNTAIN, JAKE - University Of Georgia
item BAJAJ, PRASAD - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item PANDEY, MANISH - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item NAYAK, SPURTHI - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item KUMAR, VINAY - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item JAYALE, ASHWIN - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item CHITIKINENI, ANU - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item YANG, LIMING - University Of Georgia
item LEE, ROBERT - University Of Georgia
item KEMERAIT, ROBERT - University Of Georgia
item VARSHNEY, RAJEEV - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Guo, Baozhu

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/29/2015
Publication Date: 10/29/2015
Citation: Fountain, J.C., Bajaj, P., Pandey, M., Nayak, S.N., Kumar, V., Jayale, A.S., Chitikineni, A., Yang, L., Lee, R.D., Kemerait, R.C., Varshney, R.K., Guo, B. 2015. Transcriptomic analysis reveal diverse responses to environmental oxidative stress in Aspergillus flavus [abstract]. University of Georgia Plant Center Retreat Meeting.

Interpretive Summary:

Technical Abstract: Drought stress predisposes oilseed crops such as maize and peanut to infection by Aspergillus flavus resulting in their contamination with aflatoxins. Drought stress in plants results in the accumulation of reactive oxygen species (ROS) in their tissues, and these ROS have been shown to stimulate aflatoxin production by A. flavus in vitro. In order to examine the role of aflatoxin in oxidative stress responses in A. flavus and its regulation, we sequenced the transcriptomes of toxigenic and atoxigenic isolates cultured in aflatoxin conducive and non-conducive media with varying levels of applied oxidative stress. It was found that changing media carbon sources to modulate aflatoxin production radically affected the overall expression profiles of the isolates. Isolates possessing higher levels of oxidative tolerance also exhibited fewer significantly, differentially expressed genes (DEGs) than those with lower degrees of tolerance. In addition, toxigenic isolates which produce higher levels of aflatoxin tended to exhibit fewer DEGs than those which produce lower levels of aflatoxin. Finally, genes related to iron metabolism and the production of kojic acid were also regulated in response to increasing stress along with the expression of several antioxidant enzymes. It was found that increased oxidative stress correlated with increased production of kojic acid by several of the isolates. In addition, isolates which tolerate less oxidative stress also tended to produce less kojic acid. This indicates that the sequestration of excess iron cations and ROS through enzymatic and secondary metabolic processes may form the basis of the A. flavus oxidative response system. Continuing analyses will further examine the precise role of aflatoxin in this response.