Human maladies associated with consumption of fumonisin-F. verticillioides contaminated corn are esophageal cancer and human birth disorders such as neural tube defects in babies and craniofacial abnormalities. Little is known concerning effective control strategies for such intimate systems. Removal of the fungi is not possible. Under such conditions, millions of dollars are lost due to condemnations of grain.

We have a replacement organism, an endophytic plant friendly bacterium, Bacillus mojavensis, that offers remarkable biocontrol possibilities. However, field strategies utilizing this bacterium might be confounded by additional problems that we proposed to study and solve.

Since there is a possibility that the control bacterium may exchange DNA materials with pathogenic bacteria, we propose to study the potential for this exchange referred to as horizontal gene transfer. This represents the first attempt by ARS to study this mechanism as a food safety issue, the results from which can make a fundamental change in the way we address food safety issues in plants.

Studies will be conducted on the ecological, genetics and fungus interaction with the bacterium resulting in biocontrol. These studies will utilize field trials, tests for action of one fungal inhibitor the surfactins, molecular genetics of corn, the fungus and bacterium for key control points during the endophytic relationship.

Our goal is to provide the technology to control F. verticillioides and reduce the fumonisins in corn, while providing additional food safety information on the use of biocontrol endophytic bacteria.

There are three objectives: Objective 1: Determine the potential and genetic mechanisms involved in horizontal gene transfer from Gram-negative pathogenic bacteria to a plant friendly Gram-positive bacterial endophyte B. mojavensis affecting its use as a desirable biocontrol potential.

Objective 2: Determine the diversity, evolution, and function of bacterial endophytes in cornfield environments and their impact on the metabolic activity of F. verticillioides, including the production of mycotoxins as well as the detoxification/inactivation of xenobiotic compounds.

Objective 3: Determine how biocontrol organisms can be effectively utilized to prevent the accumulation of the fumonisins, specifically the enhancement of plant defense strategies and production of the antifungal agent surfactin by B. mojavensis.

We will obtain a greater understanding of the basic biology behind ¯the why the majority of F. verticillioides strains produce fumonisins, and its interaction with biocontrol bacteria and hosts. We will also gain greater understanding of F. verticillioides metabolic pathways and the potential value of proteins involved. Patents are expected based on specific strains of the biocontrol bacterium B. mojavensis, fungicidal products produced by these bacteria, and an understanding of the role and importance of specific surfactins necessary for the biocontrol of F. verticillioides under field conditions. Research publications will detail management strategies for obtaining fungal and or toxin-free corn and corn products, novel mechanisms of control, potential biotechnological uses for novel proteins (e.g., value of xenobiotic detoxifying enzymes for remediation purposes).