Evidence that a new antibiotic flavone glycoside chemically defends the sea grass Thalassia testudinum against zoosporic fungi

Significantly fewer thraustochytrid protists (zoosporic fungi) were observed in association with healthy leaf tissue of the marine angiosperm Thalassia testudinum than in association with sterilized samples that were returned to the collection site for 48 h. In support of the hypothesis that sea gra...

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Bibliographic Details
Published in:Applied and environmental microbiology 1998-04, Vol.64 (4), p.1490-1496
Main Authors: Jensen, P.R. (University of California-San Diego, La Jolla, CA.), Jenkins, K.M, Porter, D, Fenical, W
Format: Article
Language:English
Subjects:
ANGIOSPERMAS
ANGIOSPERME
ANGIOSPERMS
Animal, plant and microbial ecology
ANTIBIOTIC PROPERTIES
ANTIBIOTICOS
ANTIBIOTICS
ANTIBIOTIQUE
Biological and medical sciences
CHAMPIGNON
DEFENCE MECHANISMS
Fundamental and applied biological sciences. Psychology
Fungal plant pathogens
FUNGI
General Microbial Ecology
GLICOSIDOS
GLYCOSIDE
GLYCOSIDES
Grasses
HONGOS
Marine
MECANISME DE DEFENSE
MECANISMOS DE DEFENSA
Microbial ecology
Microbiology
Microflora of plants
Pathology, epidemiology, host-fungus relationships. Damages, economic importance
Phytopathology. Animal pests. Plant and forest protection
PROPIEDADES ANTIBIOTICAS
PROPRIETE ANTIBIOTIQUE
Thalassia testudinum
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Summary:Significantly fewer thraustochytrid protists (zoosporic fungi) were observed in association with healthy leaf tissue of the marine angiosperm Thalassia testudinum than in association with sterilized samples that were returned to the collection site for 48 h. In support of the hypothesis that sea grass secondary metabolites were responsible for these differences, extracts of healthy T. testudinum leaf tissues inhibited the growth of the co-occurring thraustochytrid Schizochytrium aggregatum and deterred the attachment of S. aggregatum motile zoospores to an extract-impregnated substrate. By using S. aggregatum for bioassay-guided chemical fractionation, a new flavone glycoside was isolated and structurally characterized as luteolin 7-O-beta-D-glucopyranosyl-2"-sulfate. Whole-leaf tissue concentrations of this metabolite (4 mg/ml of wet leaf tissue) inhibited S. aggregatum attachment, and a significantly lower concentration (270 micrograms/ml) reduced thraustochytrid growth by 50%, suggesting that natural concentrations are at least 15 times greater than that needed for significant microbiological effects. These results offer the first complete chemical characterization of a sea grass sulfated flavone glycoside and provide evidence that a secondary metabolite chemically defends T. testudinum against fouling microorganisms
ISSN:0099-2240
1098-5336
DOI:10.1128/aem.64.4.1490-1496.1998