Abstract Detail

Poster Session

Moore, Geromy [1].

Turn on your love light: A heritability study using eGFP-transformed Aspergillus flavus.

Inoculation of agricultural fields with non-aflatoxigenic Aspergillus flavus appears to be the preferred method for pre-harvest biocontrol of aflatoxin contamination of corn, cottonseed, and peanut.  The reasons for using these A. flavus strains are beliefs that they (1) maintain persistent control in the field, and (2) are incapable of out-crossing. What is needed is a means of easily tracking field-released biocontrol strains to study their movement and longevity. Incorporating a naturally-occurring target, such as enhanced green fluorescent protein (eGFP), into a biocontrol strain might allow us to easily follow its activity in a field setting. The success of long-term field testing of eGFP-expressing A. flavus strains depends on their ability to maintain fluorescence throughout multiple generations of growth. Additionally, to ensure accurate tracking of the fluorescent atoxigenic strain, the likelihood of their out-crossing with individuals from the native population should be determined.  In vitro mating experiments paired each of six different eGFP-transformed atoxigenic strains with a toxigenic A. flavus isolate that has proven fecundity in previous mating experiments.  Results indicate that the eGFP gene, and possibly the aflatoxin cluster, is heritable by the F1 progeny.  Not all cultured ascospores were fluorescent, but subsequent out-growth arising from a single fluorescent ascospore exhibited fluorescence similar to the eGFP parent.  Observed mixed-fluorescence among conidia in a single chain suggests heterokaryosis at the moment of conidiogenesis. Mycotoxin assays showed that some fluorescent F1 individuals produce aflatoxin and/or cyclopiazonic acid (CPA) and would indicate they are recombinant offspring. These findings lend support to concerns that atoxigenic strains introduced into field environments are not impervious to genetic recombination which could pose a risk of increasing aflatoxin contamination in treated fields.

1 - United States Department of Agriculture-ARS, Food and Feed Safety Research, 1100 Robert E Lee Blvd, New Orleans, LA, 70124, USA

Keywords:
biocontrol agent
fungal out-crossing
eGFP inheritance
mycotoxin inheritance.

Presentation Type: Offered Paper - Poster
Session: P3
Location: Lincoln Room/Kellogg Hotel and Conference Center
Date: Monday, June 9th, 2014
Time: 8:00 PM
Number: P3003
Abstract ID:18
Candidate for Awards:None