Phytoparasitica (2004) 32, 192-193

E. Inbar, S.J. Green, P. Bucki, Y. Hadar and D. Minz (2004)
Characterization of Streptomyces structure in Pythium-suppressive and -non-suppressive compost-amended plant systems
Phytoparasitica 32 (2), 192-193
lecture presented at the 25th Congress of the Israeli Phytopathological Society, Febr. 2004, Bet Dagan, Israel
Abstract: A study was conducted of the disease-suppressive capability of three different composts in a compost.pathogen.plant experimental system, and associated bacterial populations were characterized. Cucumber plants were grown in compost-amended potting mixes inoculated with Pythium mycelium, with a peat-only treatment serving as a control. Disease rates were determined 21 days after planting. Two of three composts were effective in reducing damping off, a disease caused by the pathogenic Oomycete Pythium. Our microbial analyses were focused on the antibioticproducing genus Streptomyces (Class Actinobacteria) using PCR primers and culturing media selective for Streptomyces and Actinobacteria, respectively. Concurrent to isolation of specific bacterial populations, DNA was extracted from potting mix (0, 1, 4, and 21 days), seed (1 day), seedling (4 days), rhizosphere (21 days) and root (21 days) samples. Using denaturing gradient gel electrophoresis (DGGE) of PCR-generated rDNA fragments, Streptomyces populations from these samples were profiled. Prominent DGGE bands were excised and sequenced, and the phylogeny of the respective organisms was inferred. Compost application yielded significantly different population profiles at both levels of taxonomic analysis (i.e., Actinobacteria and Streptomyces). Variations between composts were significantly greater than variations between Pythium-amended and control treatments. The physiology and distribution of relevant organisms, including those detected only in Pythium-amended treatments, were discussed.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Yitzhak Hadar

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
surveys/distribution/isolation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pythium (genus)
Streptomyces (genus - antagonists)	Pythium (genus)