Project Number: 6435-42000-020-00
Project Type: Appropriated

Start Date: Dec 28, 2005
End Date: Dec 27, 2010

Objective:
(1) Improve manufacture and formulation of ATOX for management of aflatoxin contamination. Specifically address problems in applying atoxigenic strain technology to commercial practice and optimize formulation for successful delivery of biocontrol agents. (2) Characterize influences of agronomic practices (tillage, irrigation, crop rotation, application strategy) on biocontrol of aflatoxin contamination and optimize field use of ATOX on a commercial scale. (3) Develop an epidemiological model to explain formation of aflatoxins in Texas and Arizona, with emphasis on the contamination after crop maturation (the second phase of contamination). (4) Characterize the major vegetative compatibility groups (VCGs) associated with Arizona and Texas agriculture and associated niches, and test geographical and niche specialization in order to improve understanding of the etiology of contamination and selection of ATOX with improved competitive ability in target crops/areas. Develop both a single nucleotide polymorphism (SNP) database and molecular tracking techniques useful in characterizing the composition of A. flavus communities, at both the strain and VCG level on crops and in the environment. (5) Characterize A. flavus responses to varying environments and ecological niches (including animal and plant hosts) to assess fungal adaptations leading to niche competence and to facilitate selection of elite biocontrol strains and development of management practices. Data will be used to contribute to select elite biocontrol strains with improved efficacy and safety. Objectives 1-5 address development of a knowledge base and technologies that could have generic value in protection of all the crops vulnerable to aflatoxin contamination.

Approach:
Develop improved formulations and production techniques to address problems in commercial practice of biological control and to increase efficacy against aflatoxin producing fungi. Through field tests and retrospective analyses, characterize influences of agronomic practices on biological control and use recommendations. Apply geostatistical and epidemiological tools to development of a model to predict aflatoxin contamination after crop maturation. Collect representative A. flavus from crops in Texas and Arizona and characterize strain specialization, adaptive traits, and optimal atoxigenic strains for distinct cropping systems. Develop both a SNP database for differentiating distinct A. flavus strains and a molecular technique for quantifying strain incidence in environmental samples. Select elite biocontrol strains based on improved knowledge of A. flavus adaptations and responses to relevant environments and ecological niches.