Journal of Invertebrate Pathology (1998) 72, 296-303
J. Gross, C. Müller, A. Vilcinskas, M. Hilker (1998)
Antimicrobial activity of the exocrine glandular secretions, hemolymph and larval regurgitate of the mustard leaf beetle Phaedon cochleariae
Journal of Invertebrate Pathology 72 (3), 296-303
Abstract: Larvae and adults of the mustard leaf beetle Phaedon cochleariae (Coleoptera: Chrysomelidae) possess exocrine glands with secretions which are used in defense against predators. This study addressed the question whether these defensive secretions also display antimicrobial activity. Additionally, the effects of larval and adult hemolymph and larval regurgitate toward microorganisms were examined. The larval glandular secretion showed growth-inhibitory activity against the gram-negative bacterium Escherichia coli,
but no lytic effect against cell walls of the grampositive bacterium Micrococcus luteus. Growth of the yeast Saccharomyces cerevisiae and of the entomopathogenic fungus Beauveria bassiana was also inhibited by the larval secretion. The antibacterial and antifungal activity of the larval secretion was found to be due to its main component, the iridoid monoterpene, (epi)chrysomelidial. The mechanism of its antifungal activity was examined by different bioassays and compared to the commercially available fungicide nystatin. The antifungal activity of the larval secretion is not due to a loss of intracellular potassium in treated fungal cells, while high potassium efflux from treated cells is the mode of action of common fungicides. The larval secretion exhibited direct cytotoxicity against both fungal cells and plasmatocytes isolated from the greater wax moth Galleria mellonella. In contrast to the larval secretion, the adult glandular secretion of P. cochleariae showed lytic activity against the cell walls of the gram-positive bacterium M. luteus, but no activity against the gram-negative bacterium E. coli and eukaryotic cells. Hemolymph and larval regurgitate of P. cochleariae displayed the same activity as the tested glandular secretion of adults.
(The abstract has been supplied by the author or ISPI and is excluded from the Creative Commons licence.)
Database assignments for author(s): Jürgen Gross, Monika Hilker
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Phaedon cochleariae | Cabbage (Brassica oleracea) | Germany |
