Location: Crop Protection and Management ResearchTitle: The potential role of oxidative stress in Aspergillus flavus survivability and aflatoxin biosynthesis Author
|Fountain, Jake - University Of Georgia|
|Yang, Liming - University Of Georgia|
|Khera, Pawan - University Of Georgia|
|Kemerait, Robert - University Of Georgia|
|Lee, R - University Of Georgia|
|Varshney, Rajeev - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2014
Publication Date: 11/9/2014
Citation: Fountain, J.C., Yang, L., Khera, P., Kemerait, R.C., Lee, R.D., Varshney, R.K., Scully, B.T., Guo, B. 2014. The potential role of oxidative stress in Aspergillus flavus survivability and aflatoxin biosynthesis. Meeting Abstract. Advances in Arachis through Genomics and Biotechnology (AAGB) meeting, November 10-14, 2014, Savannah, Georgia.
Technical Abstract: Aflatoxin contamination of food and feed occurs due to growth of Aspergillus flavus. This poses a serious health risk because of aflatoxin’s toxic and carcinogenic properties which negatively impact human and livestock health. Colonization and subsequent aflatoxin production by A. flavus is typically associated with stressed crops in the field. The purpose of aflatoxin biosynthesis, however, is not well understood. The objective of this study was to examine the possible association of oxidative stress, survivability, and aflatoxin biosynthesis in different A. flavus isolates. Eight isolates were used, including both toxigenic (+) and atoxigenic (-) isolates: NRRL3357(+), A9(+), AF13(+), A1(-), K49(-), K54(-), AF36(-), and Aflaguard(AF-). Fungal biomass was recorded following culture in yeast extract-sucrose (YES) media supplemented with hydrogen peroxide (H2O2) with a concentration gradient from 0 to 40 mM in 5mM increments for 7 days at 32°C in either stationary or shaking (100 rpm) conditions. Fungal growth was significantly affected at varying H2O2 concentrations, and the presence or absence of shaking did not significantly affect survivability. The toxigenic isolates were able to survive up to 20 to 35mM H2O2, and the atoxigenic isolates were able to survive up to 15 to 30mM H2O2. It was interesting that NRRL3357(+) survived to 20mM while K49(-) survived to 30mM. Overall, toxigenic isolates were able to survive significantly better than atoxigenic isolates over the H2O2 gradients. The general trend was more aflatoxin production with increased H2O2 concentration. Further investigation will be conducted to study the specific stress response signal genes and aflatoxin biosynthesis in different A. flavus isolates.