Location: National Peanut Research LaboratoryTitle: Developing an in vitro method to assess aflatoxin biosynthesis suppression in Aspergillus flavus through RNAi technologies
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/3/2015
Publication Date: N/A
Interpretive Summary: The filamentous fungus Aspergillus flavus is usually associated with peanut seed infections, which under favorable environmental conditions often lead to contamination with the hepatotoxic and carcinogenic compounds known as aflatoxins. At the National Peanut Research Laboratory, USDA-ARS we have engineered an RNA interference (RNAi) construct to transform the aflatoxigenic A. flavus NRRL 3357 strain. The RNAi-based molecular construct will constitute the basis for a method to control aflatoxin contamination in peanuts. This work shows the implementation of an in vitro method to screen fungal isolates that showed a reduced biosynthesis of aflatoxins. Our preliminary results indicated that some fungal isolates transformed with our RNAi construct showed a reduced aflatoxin production.
Technical Abstract: The soil-inhabitant fungus Aspergillus flavus is consistently associated with agronomical fields, where it promptly colonizes important crops such as corn (Zea mays) and peanuts (Arachis hypogaea). The consumption of A. flavus-contaminated of food grains poses a potential threat for human and animal health, and overall food security. Generally A. flavus synthesizes two major mycotoxins; aflatoxin B1, a polyketide-derived carcinogenic toxin with hepatotoxic and immunosuppressive effects in humans, and cyclopiazonic acid, an indole-tetramic acid neurotoxin that affects liver, kidney, and gastrointestinal tract in animals. It has been estimated that more than 4.5 billion people around the world are in high risk to the adverse effects of aflatoxins exposure. Therefore, the control of aflatoxin contamination in key staples requires comprehensive and sound approaches. RNA interference (RNAi) technology, which is based upon a natural process to suppress the activity of specific genes, has the potential to prevent mycotoxins accumulation in crops. In our study, we have developed a system to evaluate in vitro the effectiveness of RNAi-based molecular constructs in suppressing aflatoxin biosynthesis, as preliminary screening before using these constructs in plants.