Affiliation:
1. Department of Entomology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster, Ohio 44691
Abstract
ABSTRACT
Moraxella osloensis
, a gram-negative bacterium, is associated with
Phasmarhabditis hermaphrodita
, a nematode parasite of slugs. This bacterium-feeding nematode has potential for the biological control of slugs, especially the grey garden slug,
Deroceras reticulatum
. Infective juveniles of
P. hermaphrodita
invade the shell cavity of the slug, develop into self-fertilizing hermaphrodites, and produce progeny, resulting in host death. However, the role of the associated bacterium in the pathogenicity of the nematode to the slug is unknown. We discovered that
M. osloensis
alone is pathogenic to
D. reticulatum
after injection into the shell cavity or hemocoel of the slug. The bacteria from 60-h cultures were more pathogenic than the bacteria from 40-h cultures, as indicated by the higher and more rapid mortality of the slugs injected with the former. Coinjection of penicillin and streptomycin with the 60-h bacterial culture reduced its pathogenicity to the slug. Further work suggested that the reduction and loss of pathogenicity of the aged infective juveniles of
P. hermaphrodita
to
D. reticulatum
result from the loss of
M. osloensis
from the aged nematodes. Also, axenic J1/J2 nematodes were nonpathogenic after injection into the shell cavity. Therefore, we conclude that the bacterium is the sole killing agent of
D. reticulatum
in the nematode-bacterium complex and that
P. hermaphrodita
acts only as a vector to transport the bacterium into the shell cavity of the slug. The identification of the toxic metabolites produced by
M. osloensis
is being pursued.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
86 articles.
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