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