Applied and Environmental Microbiology (2006) 72, 6452-6460

Paul J. Hunter, Geoff M. Petch, Leo A. Calvo-Bado, Tim R. Pettitt, Nick R. Parsons, J. Alun W. Morgan and John M. Whipps (2006)
Differences in microbial activity and microbial populations of peat associated with suppression of damping-off disease caused by Pythium sylvaticum
Applied and Environmental Microbiology 72 (10), 6452-6460
Abstract: The microbiological characteristics associated with disease-suppressive peats are unclear. We used a bioassay for Pythium sylvaticum-induced damping-off of cress seedlings to identify conducive and suppressive peats. Microbial activity in unconditioned peats was negatively correlated with the counts of P. sylvaticum at the end of the bioassay. Denaturing gradient gel electrophoresis (DGGE) profiling and clone library analyses of small-subunit rRNA gene sequences from two suppressive and two conducive peats differed in the bacterial profiles generated and the diversity of sequence populations. There were also significant differences between bacterial sequence populations from suppressive and conducive peats. The frequencies of a number of microbial groups, including the Rhizobium-Agrobacterium group (specifically sequences similar to those for the genera Ochrobactrum and Zoogloea) and the Acidobacteria, increased specifically in the suppressive peats, although no single bacterial group was associated with disease suppression. Fungal DGGE profiles varied little over the course of the bioassay; however, two bands associated specifically with suppressive samples were detected. Sequences from these bands corresponded to Basidiomycete yeast genera. Although the DGGE profiles were similar, fungal sequence diversity also increased during the bioassay. Sequences highly similar to those of Cryptococcus increased in relative abundance during the bioassay, particularly in the suppressive samples. This study highlights the importance of using complementary approaches to molecular profiling of complex populations and provides the first report that basidiomycetous yeasts may be associated with the suppression of Pythium-induced diseases in peats.
(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): T.R. Pettitt, J. Alun W. Morgan

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Globisporangium sylvaticum