Plant Pathology (2000) 49, 523-530

M. Ongen, F. Daayf, P. Jacques, P. Thonart, N. Benhamoud, T.C. Paulitze and R.R. Bélanger (2000)
Systemic induction of phytoalexins in cucumber in response to treatments with fluorescent pseudomonads
Plant Pathology 49 (4), 523-530
Abstract: The Pseudomonas putida isolate BTP1 and its sid^- mutant M3 were recently reported to protect cucumber against Pythium aphanidermatum root rot. This protection was mainly associated with an accumulation of antifungal phenolics in the treated roots. In this study, analyses of root extracts from split-root experiments showed that these phytoalexins were produced systemically. Indeed, several antifungal molecules accumulated similarly in both treated and nontreated root parts of plants protected against P. aphanidermatum with BTP1 or M3. In addition, analyses of leaf samples also revealed increased amounts of fungitoxic molecules in PGPR-treated plants, although the nature of these molecules appeared to be different from those detected in roots. The antifungal compounds isolated both from roots and leaves were mainly detected in acid-hydrolyzed extracts containing aglycones. These results suggest that PGPR can elicit phytoalexins systemically in cucumber and that the overall defence response is not based on a single phytoalexin but is chemically complex and organ-specific.
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Database assignments for author(s): Richard R. Belanger, Fouad Daayf

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pythium aphanidermatum	Cucumber (Cucumis sativus)
Pseudomonas putida (antagonist)	Pythium aphanidermatum	Cucumber (Cucumis sativus)