Submitted to: Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2015
Publication Date: 12/2/2015
Citation: Olanya, O.M., Lakshman, D.K. 2015. Potential of predatory bacteria as biocontrol agents for foodborne and plant pathogens. Journal of Plant Pathology. 97:405-417.
Interpretive Summary: The Control of bacterial contamination on minimally processed produce (fruits and vegetables)at post harvest is crucial for consumer safety. Similarly, pre-harvest losses in crop yield and quality due to plant pathogenic bacteria are of concern to producers. Although various research on the use of predatory bacteria (Bdellovibrio, Bacteriovorax and Bdellovibrio like organisms (BALOs) has been documented, practical utilization of the above potential biocontrol agents are limited. To complement post-harvest intervention measures for foodborne and plant pathogens on produce (fruits and vegetables), we review the possibility of controlling foodborne bacteria and phytopathogens with predatory bacteria. The ecology and diversity of the biocontrol microbes, types and mechanisms of their predation, lifecycle, as well as their attributes and limitations are presented by highlighting examples from published research. If extensively applied, the biocontrol agents (predatory bacteria) will significantly enhance and complement the postharvest control of foodborne and plant pathogens on produce.
Technical Abstract: Foodborne pathogens such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Shigella are responsible for frequent occurrences of illnesses and mortality in humans and produce losses. Pre-harvest yield losses and post-harvest decay on minimally processed produce (fruits, vegetables) are also incited by plant pathogens such as Erwinia, Pectobacterium, Botrytis, Pseudomonas spp. The Delta proteobacetria (Bdellovibrio and Bacteriovorax sp.) and the Alphaproteobacteria Micavibrio aeruoginosavorus are Gram-negative predatory bacteria which are adapted to diverse ecologies. The predation of Gram negative bacteria may be applied for potential biocontrol of foodborne and plant pathogens. The rationale for using predatory bacteria (PB) is that foodborne and plant pathogenic bacteria are difficult to control because of the paucity of available bactericidal chemicals and regulations on the use of antibiotics in disease control. The types and mechanisms of predation by PB are discussed in this review with respect to their potential utilization as biocontrol agents. The genomic approaches are presented to highlight their diversity and relationships to other prokaryotes. The biocontrol potential of foodborne and plant pathogens is discussed in the context of attributes and limitations of predatory bacteria. Although research in animal systems (Salmonella /chicken) indicates significant biocontrol potential when PB are applied as probiotics, applications to foodborne and plant pathogens are still at its infancy. As progress in metagenomics and on PB effects on animal cells/tissues continues, it is anticipated that a better understanding of regulation of cellular metabolic events associated with growth of PB and prey degradation will ultimately enhance the utility of PB as biocontrol agents of foodborne and plant pathogens.