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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Toxicology & Mycotoxin Research » Research » Publications at this Location » Publication #344285

Research Project: Eliminating Fusarium Mycotoxin Contamination of Corn by Targeting Fungal Mechanisms and Adaptations Conferring Fitness in Corn and Toxicology and Toxinology Studies of Mycotoxins

Location: Toxicology & Mycotoxin Research

Title: Atoxigenic strains of Aspergillus flavus isolated from peanuts collected from northern Philippines as potential biocon agents against pre-harvest aflatoxin contamination of peanut and corn

item LUIS, JANET - Benguet State University
item Glenn, Anthony - Tony
item KEMERAIT, ROBERT - University Of Georgia
item AGUSTIN, FLORESCA - Benguet State University
item Pierce, Larry
item ANGELES, YOLANDA - Don Mariano Marcos Memorial State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Aflatoxin contamination of food products causes liver cancer and weakened immunity in humans, and stunted growth and reduced productivity in animals (CAST, 2003). Effective control of pre-harvest aflatoxin contamination of peanut and corn due to AflaGuard and Aflasafe in the United States and Africa, respectively, have been achieved. Nevertheless, these products cannot be used locally due to ecological differences in micro-biodiversity. Thus, the study was conducted at BSU in search for local atoxigenic strains of Aspergillus flavus (ASAFs) in peanuts grown in Northern Philippines as potential biocon agents against pre-harvest aflatoxin contamination of peanut and corn. One hundred sixty and five peanut samples were collected from the Cordillera Administrative Region (CAR), and Regions I and II. Randomly selected kernel samples from each were processed for qualitative aflatoxin detection using immunochromatographic strips. Only samples showing negative reaction to the strips, i.e. indication of freedom from 20ppb aflatoxin content cutoff for acceptance of product as food, were used to isolate Aspergillus section Flavi (AF) members, eliminating all other isolates via morphological characterization. These were sent by freight to USDA for the detection of defective aflatoxin biosynthetic gene cluster (ABGC) via multiplex PCR and confirmation of non-production of aflatoxin by defective strains via back inoculation to rice grains then extraction of metabolite for detection via liquid chromatography - mass spectrometry following the protocols of Callicott and Cotty (2014). There were 440 AF isolates prepared and sent for molecular fingerprinting. The first cycle of multiplex PCR showed 25 isolates to have defective ABGC: four A. flavus strains with lack of full cluster (permanent mutation), 11 isolates as A. tamarii, and 10 isolates of unknown species. The second cycle of multiplex PCR showed six A. flavus strains with lack of partial cluster (partial mutation) but one was contaminated with bacterium and other fungus, thus eliminated. The four permanent mutants and five partial mutants did not produce cyclopinozoic acid (CPA) or aflatoxin. Results show that the four permanent mutants are potential biocon agents against pre-harvest aflatoxin contamination of peanut and corn. Possible use of the partial mutants is also being considered with extra care in avoiding their possible hybridization with the permanent mutants. Immediate efforts to come up with protocols on the production of inoculants and proper field application are now being addressed.