An approach for identifying microorganisms involved in soil suppressiveness: Utilization for identifying microorganisms that suppress the plant-parasitic nematode, Heterodera schachtii

An approach was developed for identifying microorganisms involved in soil suppressiveness. Phase one of the approach employed an rRNA gene (rDNA) method to identify bacteria and fungi that positively correlated with soil suppressiveness against the plant-parasitic nematode, Heterodera schachtii. Fiv...

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Bibliographic Details
Published in:Phytopathology 2004-06, Vol.94 (6)
Main Authors: Olatinwo, RO, Yin, B, Becker, JO, Borneman, J
Format: Article
Language:English
Subjects:
Dactylella oviparasitica
Fusarium oxysporum
Heterodera schachtii
Zoogloea
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Summary:An approach was developed for identifying microorganisms involved in soil suppressiveness. Phase one of the approach employed an rRNA gene (rDNA) method to identify bacteria and fungi that positively correlated with soil suppressiveness against the plant-parasitic nematode, Heterodera schachtii. Five soil treatments, generated by mixing different amounts of suppressive and fumigation-induced non-suppressive soil, were infested with H. schachtii juveniles and cropped with Swiss chard. After two nematode generations, the most abundant fungal and bacteria rDNA sequences found in H. schachtii cysts isolated from the highly suppressive soils had high identity to Dactylella oviparasitica and Zoogloea sp. rDNA, respectively. The most abundant fungal rDNA sequences found in H. schachtii cysts isolated from the minimally to moderately suppressive soils had high identity to Fusarium oxysporum rDNA. Phase two confirmed these population trends using sequence-selective quantitative PCR. In phase three, strains of D. oviparasitica, F. oxysporum and the Zoogloea sp. were isolated from H. schachtii cysts and reintroduced into non-suppressive soil; F. oxysporum and the Zoogloea sp. did not significantly decrease H. schachtii populations, while D. oviparasitica decreased H. schachtii populations to levels equivalent to that produced by the suppressive soil. This experimental approach should be useful for investigations of other suppressive soils and for identifying microorganisms involved in other functions.
ISSN:0031-949X