BACTERIAL SYMBIONTS OF ENTOMOPATHOGENIC NEMATODES AS BIOCONTROL AGENTS

Abstract

Bacteria of the genera Photorhabdus spp. and Xenorhabdus spp. form a mutually beneficial symbiotic complex with the entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematidae, respectively, which are able to infect, kill and reproduce in many insect species. These bacteria produce insecticidal factors which are critical for their pathogenic activities on insects. The bacteria produce a range of proteins and metabolites that work as fungicidal, nematicidal and insecticidal. These bacteria secrete entomopathogenic factors directly into the growth medium. Interestingly, these bacteria or their toxic factors are insecticidal when they are ingested through the mouth and when they are injected into the hemolymph. There have been several reports of fungicidal, nematocidal activities and oral toxicity of symbiotic bacteria and their toxins.