Abstract
Abstract A possible mechanism of suppression of a plant-parasitic nematode Meloidogyne incognita by entomopathogenic nematodes is described. Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect. Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria. They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively. Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration. Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs. Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial. The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium. These results demonstrate allelopathic interactions between plant-parasitic nematodes, entomopathogenic nematodes and their symbiotic bacteria. The likely role of allelopathy in the suppression of plant-parasitic nematodes by innundative applications of entomopathogenic nematodes is discussed. Allelopathie: Ein moglicher Mechanismus zur Unterdruckung pflanzenparasitarer Nematoden durch insektenpathogene Nematoden - Es wird ein moglicher Mechanismus zur Unterdruckung des pflanzenparasitaren Nematoden Meloidogyne incognita durch insektenpathogene Nematoden beschrieben. Durch Hitze abgetotete insektenpathogene Nematoden Steinernema feltiae und S. riobrave underdruckten das Eindringen des Wurzelgallenalchens M. incognita in Tomatenwurzeln, lebende Nematoden hatten keine Wirkung. Infektionsjuvenile von M. incognita wurden von allen Behandlungen mit insektenpathogenen Nematoden abgestossen, die auch die symbiontischen Bakterien einschlossen. Sie wurden durch die Kadaver von Galleria mellonella abgestossen, die mit S. carpocapsae, S. feltiae und S. riobrave infiziert waren sowie durch zellfreie Kultursubstrate der symbiontischen Bakterien Xenorhabdus nematophilus, X. bovienii und Xenorhabdus sp. "R" aus den drei genannten Nematodenarten. Zellfreie Kultursubstrate von allen drei Xenorhabdus spp. waren giftig fur die Infektionsjuvenilen von M. incognita und verursachten in einer Konzentration von 15% Abtotungsraten von 98-100%. Zellfreie Kultursubstrate von Xenorhabdus sp. "R" vermiderten ausserdem das Schlupfen von M. incognita-Eiern. In einem Gewachshausversuch unterdruckten formulierte zellfreie Bakterienfiltrate vorubergehend das Eindringen von M. incognita in Tomatenwurzeln. Die Kurzzeitwirkungen von zellfreien Bakterien filtraten, namentlich Giftigkeit und Abstossung, waren nahezu ganz bedingt durch Ammoniak. Diese Ergebnisse zeigen das Vorhandensein von allelopathischen Wechselwirkungen zwischen pflanzenparasitaren Nematoden, insektenpathogenen Nematoden und deren symbiontischen Bakterien. Die wahrscheinliche Rolle von Allelopathie bei der Unterdruckung pflanzenparasitarer Nematoden durch eine Massenanwendung insektenpathogener Nematoden wird diskutiert.
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Claims 10
Claim · model-written summary
Heat-killed Steinernema feltiae temporarily suppressed M. incognita penetration into tomato roots.
- Taxon
- tomato
Solanum lycopersicume0 - Treatment
- Heat-killed entomopathogenic nematodes Steinernema feltiaee0
- Interactor
- M. incognita
_penetrates_a_tomato_root_-_USDA-ARS.jpg?width=60)
Meloidogyne incognitae0pest - Second interactor
- Steinernema feltiae
Steinernema feltiaee0biocontrol_agent - Outcome
- penetration of the root-knot nematode M. incognita into tomato rootse0
- Direction
- suppressede0
- Comparator
- live nematodese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_penetrates_a_tomato_root_-_USDA-ARS.jpg?width=500)
Verbatim
e0“Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect.”
Claim · model-written summary
Heat-killed S. riobrave temporarily suppressed M. incognita penetration into tomato roots.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- S. riobravee0
- Interactor
- M. incognitaMeloidogyne incognitae0pest
- Second interactor
- S. riobraveSteinernema riobravee0biocontrol_agent
- Outcome
- penetration of the root-knot nematode M. incognita into tomato rootse0
- Direction
- suppressede0
- Comparator
- live nematodese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Heat-killed entomopathogenic nematodes Steinernema feltiae and S. riobrave temporarily suppressed penetration of the root-knot nematode M. incognita into tomato roots, but live nematodes had no effect.”
Claim · model-written summary
Live entomopathogenic nematodes had no effect on M. incognita root penetration.
Not reportedTaxonComparator
Verbatim
e0“but live nematodes had no effect.”
Claim · model-written summary
Symbiotic-bacteria-bearing nematode treatments repelled juvenile M. incognita.
- Treatment
- entomopathogenic nematode treatments that included their symbiotic bacteriae0
- Interactor
- M. incognitaMeloidogyne incognitae0pest
- Outcome
- Infective juvenile M. incognitae0
- Direction
- repellede0
Not reportedTaxonComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Infective juvenile M. incognita were repelled from all entomopathogenic nematode treatments that included their symbiotic bacteria.”
Claim · model-written summary
Infected Galleria cadavers repelled M. incognita juveniles.
- Treatment
- Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobravee0
- Outcome
- Theye0
- Direction
- repellede0
Not reportedTaxonComparator
Verbatim
e0“They were repelled by Galleria mellonella cadavers infected with S. carpocapsae, S. feltiae, and S. riobrave”
Claim · model-written summary
Xenorhabdus culture filtrates repelled M. incognita juveniles.
- Treatment
- cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R"e0
Not reportedTaxonComparatorOutcomeDirection
Verbatim
e0“and from cell-free culture filtrates of the symbiotic bacteria Xenorhabdus nematophilus, X. bovienii, and Xenorhabdus sp. "R" from the three nematode species, respectively.”
Claim · model-written summary
Xenorhabdus filtrates caused 98-100% mortality of M. incognita juveniles at 15% concentration.
- Treatment
- Cell-free filtrates from all three Xenorhabdus spp.e0
- Interactor
- M. incognitaMeloidogyne incognitae0pest
- Outcome
- M. incognita infective juveniles causing 98-100% mortalitye0
- Direction
- toxice0
- Value
- 98-100%e0
Not reportedTaxonComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cell-free filtrates from all three Xenorhabdus spp. were toxic to M. incognita infective juveniles causing 98-100% mortality at 15% concentration.”
Claim · model-written summary
Xenorhabdus sp. R filtrate reduced M. incognita egg hatch.
- Treatment
- Cell-free filtrate of Xenorhabdus sp. "R"e0
- Interactor
- M. incognitaMeloidogyne incognitae0pest
- Outcome
- hatch of M. incognita eggse0
- Direction
- reducede0
Not reportedTaxonComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cell-free filtrate of Xenorhabdus sp. "R" also reduced the hatch of M. incognita eggs.”
Claim · model-written summary
Formulated bacterial filtrates temporarily suppressed M. incognita penetration of tomato roots in a greenhouse.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- Application of formulated bacterial cell-free filtratese0
- Interactor
- M. incognitaMeloidogyne incognitae0pest
- Outcome
- M. incognita penetration into tomato rootse0
- Direction
- suppressede0
- Setting
- greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of formulated bacterial cell-free filtrates temporarily suppressed M. incognita penetration into tomato roots in a greenhouse trial.”
Claim · model-written summary
Authors attribute short-term filtrate toxicity and repellency almost entirely to ammonium.
Not reportedTaxon
Verbatim
e0“The short-term effects of cell-free bacterial filtrates, namely toxicity and repellency, were almost entirely due to ammonium.”
The same questions in other papers
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See all 23 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.