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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #331370

Research Project: Developing Genomic Approaches to Improve Resistance to Diseases and Aflatoxin Contamination in Peanut and Corn

Location: Crop Protection and Management Research

Title: RNAseq analysis reveals oxidative stress responses of Aspergillus flavus related to stress tolerance and aflatoxin production

Author
item Fountain, Jake - University Of Georgia
item Bajaj, Prasad - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Yang, Liming - University Of Georgia
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 Chitikineni, Anu - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Chen, Sixue - University Of Florida
item Lee, Dewey - University Of Georgia
item Scully, Brian
item Kemerait, Robert - University Of Georgia
item Varshney, Rajeev - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Guo, Baozhu

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2016
Publication Date: 7/30/2016
Citation: Fountain, J., Bajaj, P., Yang, L., Pandey, M., Nayak, S., Chitikineni, A., Chen, S., Lee, D., Scully, B.T., Kemerait, R., Varshney, R., Guo, B. 2016. RNAseq analysis reveals oxidative stress responses of Aspergillus flavus related to stress tolerance and aflatoxin production [abstract]. American Phytopathological Society Abstracts.

Interpretive Summary:

Technical Abstract: Aflatoxin contamination by Aspergillus flavus is exacerbated by drought stress in the field. Given that reactive oxygen species (ROS) both accumulate in plant tissues during drought and can stimulate aflatoxin production in vitro, we examined the responses of toxigenic isolates of A. flavus to oxidative stress focusing on secondary metabolite production using whole transcriptome sequencing. We examined two high toxin producing isolates, Tox4 and AF13, and one moderate producer, NRRL3357, in aflatoxin conducive yeast extract sucrose medium amended with various levels of H2O2. The high producers exhibited fewer differentially expressed genes (DEGs) than the moderate producer in response to increasing stress. Altered aminobenzoate degradation expression along with altered conidiation and growth also suggests reduced developmental rates in the isolates caused by oxidative stress. Aflatoxin genes were upregulated in response to increasing stress along with genes encoding aflatrem and kojic acid biosynthesis. Additional changes in primary metabolic genes also indicates adaptations to increasing stress. Given that the number and diversity of DEGs observed correlated with previously observed aflatoxin production and oxidative stress tolerance for each isolate, these data suggest that secondary metabolite production is involved in A. flavus oxidative responses. Continuing proteomic analyses using gel and iTRAQ methods are underway to confirm the transcriptome results.