Fluoroacetate in plants - a review of its distribution, toxicity to livestock and microbial detoxification

Abstract

Fluoroacetate producing plants grow worldwide and it is believed they produce this toxic compound as a defence mechanism against grazing by herbivores. Ingestion by livestock often results in fatal poisonings, which causes significant economic problems to commercial farmers in many countries such as Australia, Brazil and South Africa. Several approaches have been adopted to protect livestock from the toxicity with limited success including fencing, toxic plant eradication and agents that bind the toxin. Genetically modified bacteria capable of degrading fluoroacetate have been able to protect ruminants from fluoroacetate toxicity under experimental conditions but concerns over the release of these microbes into the environment have prevented the application of this technology. Recently, a native bacterium from an Australian bovine rumen was isolated which can degrade fluoroacetate. This bacterium, strain MFA1, which belongs to the Synergistetes phylum degrades fluoroacetate to fluoride ions and acetate. The discovery and isolation of this bacterium provides a new opportunity to detoxify fluoroacetate in the rumen. This review focuses on fluoroacetate toxicity in ruminant livestock, the mechanism of fluoroacetate toxicity, tolerance of some animals to fluoroaceate, previous attempts to mitigate toxicity, aerobic and anaerobic microbial degradation of fluoroacetate, and future directions to overcome fluoroacetate toxicity.

A reappraisal on biodegradation of fluoride compounds: role of microbes

“…B, Pseudomonas fluorescens DSM8341 and a soil Pseudomonas sp. (Leong et al 2017). The enzyme fluoroacetate dehalogenase is known for its ability to cleave the highly stable carbon-fluorine bond (Donnelly & Murphy 2009).…”

“…(Leong et al . ). The enzyme fluoroacetate dehalogenase is known for its ability to cleave the highly stable carbon–fluorine bond (Donnelly & Murphy ).…”

Dehalogenases: From Improved Performance to Potential Microbial Dehalogenation Applications

“…The important role of residues His 109 , Asp 134 , Lys 181 , and His 280 have also been predicted to be useful in de novo enzyme designing in enhancing the C-F or C-Cl bond cleavage [ 78 ]. Several soil bacteria play a role in defluorination of fluoroacetate, and the fluoroacetate dehalogenase enzymes identified in some of these bacteria appear to degrade fluoroacetate via a similar mechanism ( Figure 3 ), and more strikingly, bacteria harboring two haloacetate dehalogenase enzymes—fluoroacetate dehalogenase H-1 (dehH1) and fluoroacetate dehalogenase H-2 (dehH2)—have only been described in Delftia acidovorans strain B [ 79 , 80 ]. The amino acid sequence of fluoroacetate dehalogenase from Moraxella Sp.…”

“…Other dehalogenase-producing strains like the native bacterium strain MFA1, which belongs to the Synergistetes phylum of the Australian bovine rumen have been isolated using anaerobic agar plates with amino acids metabolized in the presence of fluoroacetate as a carbon source [ 80 , 211 ]. Few soil microorganisms that can utilize short-chain haloalkanoic acids such as chloroacetate and 2-chloropropionate as their sole carbon source have evolved over time [ 92 ].…”

“…Genetically modified fluoroacetate dehalogenase-producing bacteria capable of degrading fluoroacetate have been developed to protect ruminants from fluoroacetate toxicity. The fluoroacetate dehalogenase enzymes identified in some of these bacteria appear to degrade fluoroacetate, where an ester is produced as an intermediate which is hydrolyzed by a water molecule to form glycolate [ 80 ].…”