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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #329426

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

Location: Crop Protection and Management Research

Title: Gene expression profiles of Aspergillus flavus isolates responding to oxidative stress in different culture media

Author
item Fountain, Jake - University Of Georgia
item Yang, L - University Of Georgia
item Kemerait, R - University Of Georgia
item Bajaj, P - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Pandey, M - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Nayak, S - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Jayale, A - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Kumar, V - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Chitikineni, A - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Varshney, R - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India
item Chen, S - University Of Florida
item Lee, R - University Of Georgia
item Scully, Brian
item Guo, Baozhu

Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2016
Publication Date: 7/12/2016
Citation: Fountain, J.C., Yang, L., Kemerait, R.C., Bajaj, P., Pandey, M., Nayak, S.N., Jayale, A.S., Kumar, V., Chitikineni, A., Varshney, R.K., Chen, S., Lee, R.D., Scully, B.T., Guo, B. 2016. Gene expression profiles of Aspergillus flavus isolates responding to oxidative stress in different culture media [abstract]. American Peanut Research and Education Society Abstracts.

Interpretive Summary:

Technical Abstract: Aflatoxin contamination of peanut by Aspergillus flavus is exacerbated by drought stress. Drought also stimulates the production of reactive oxygen species (ROS) in plant tissues implying a correlation between ROS and aflatoxin production. Here, we performed gene expression analysis by RNAseq of toxigenic and atoxigenic isolates of A. flavus in aflatoxin conducive and non-conducive culture medium amended with various levels of H2O2. In total we generated 282.6 Gb of sequencing data with an average of 40.3 million filtered reads per sample of which 92.3% mapped to the A. flavus NRRL3357 genome. In general, isolates with greater oxidative stress tolerance and higher aflatoxin production exhibited fewer differentially expressed genes (DEGs) than less tolerant, atoxigenic isolates (r < -0.6). Genes involved in cell wall maintenance, antioxidant enzyme activity, cell membrane integrity, and carbon metabolism were regulated by increasing stress to different extents depending on medium carbon source. Fungal development pathways were also regulated in response to increasing stress more prevalently in less tolerant isolates indicating that delayed development may contribute to the overall differential expression patterns. Secondary metabolite production was also shown to be affected by oxidative stress and carbon source including aflatoxin and kojic acid. The expression of genes involved in aflatrem production were also regulated in a similar fashion to aflatoxin genes. Overall, these data suggest that the production of aflatoxin, aflatrem, and kojic acid are involved in A. flavus oxidative stress responses.