Applied and Environmental Microbiology (2009) 75, 4790-4800

Jessica Vallance, Gaétan Le Floch, Franck Déniel, Georges Barbier, C. André Lévesque and Patrice Rey (2009)
Influence of Pythium oligandrum biocontrol on fungal and oomycete population dynamics in the rhizosphere
Applied and Environmental Microbiology 75 (14), 4790-4800
Abstract: Fungal and oomycete populations and their dynamics were investigated following the introduction of the biocontrol agent Pythium oligandrum into the rhizosphere of tomato plants grown in soilless culture. Three strains of P. oligandrum were selected on the basis of their ability to form oospores (resting structures) and to produce tryptamine (an auxin-like compound) and oligandrin (a glycoprotein elicitor). Real-time PCR and plate counting demonstrated the persistence of large amounts of the antagonistic oomycete in the rhizosphere throughout the cropping season (April to September). Inter-simple-sequence-repeat analysis of the P. oligandrum strains collected from root samples at the end of the cropping season showed that among the three strains used for inoculation, the one producing the smallest amount of oospores was detected at 90%. Single-strand conformational polymorphism analysis revealed increases in the number of members and the complexity of the fungal community over time. There were no significant differences between the microbial ecosystems inoculated with P. oligandrum and those that were not treated, except for a reduction of Pythium dissotocum (ubiquitous tomato root minor pathogen) populations in inoculated systems during the last 3 months of culture. These findings raise interesting issues concerning the use of P. oligandrum strains producing elicitor and auxin molecules for plant protection and the development of biocontrol.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Patrice Rey, C. André Lévesque, Gaetan Le Floch

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
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 dissotocum	Tomato (Solanum lycopersicum)
Pythium oligandrum (antagonist)	Pythium dissotocum	Tomato (Solanum lycopersicum)