Abstract
Phytoalexin biosynthesis is part of the defense mechanism of soybean (Glycine max) plants against attack by the fungus Diaporthe phaseolorum f. sp. meridionalis (Dpm), the causal agent of stem canker disease. The treatment of soybean cotyledons with Dpm elicitor or with sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in a high accumulation of phytoalexins. This response did not occur when SNP was replaced by ferricyanide, a structural analog of SNP devoid of the NO moiety. Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors. The Dpm elicitor also induced NOS activity in soybean tissues proximal to the site of inoculation. The induced NOS activity was Ca(2+)- and NADPH-dependent and was sensitive to the NOS inhibitors N(G)-nitro-L-arginine methyl ester, aminoguanidine, and L-N(6)-(iminoethyl) lysine. NOS activity was not observed in SNP-elicited tissues. An antibody to brain NOS labeled a 166-kD protein in elicited and nonelicited cotyledons. Isoflavones (daidzein and genistein), pterocarpans (glyceollins), and flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP, although the accumulation of glyceollins and apigenin was limited in SNP-elicited compared with fungal-elicited cotyledons. NOS activity preceded the accumulation of these flavonoids in tissues treated with the Dpm elicitor. The accumulation of these metabolites was faster in SNP-elicited than in fungal-elicited cotyledons. We conclude that the response of soybean cotyledons to Dpm elicitor involves NO formation via a constitutive NOS-like enzyme that triggers the biosynthesis of antimicrobial flavonoids.
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Claims 14
Claim · model-written summary
The fungal elicitor or SNP each caused high phytoalexin accumulation.
- Taxon
- soybean
Glycine maxe0 - Treatment
- Dpm elicitor or with sodium nitroprusside (SNP)e0
- Interactor
- Dpme0pathogen
- Outcome
- accumulation of phytoalexinse0
- Direction
- highe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The treatment of soybean cotyledons with Dpm elicitor or with sodium nitroprusside (SNP), a nitric oxide (NO) donor, resulted in a high accumulation of phytoalexins”
Claim · model-written summary
Ferricyanide did not induce the response observed with SNP.
- Taxon
- soybeanGlycine maxt0
- Treatment
- ferricyanidee0
- Outcome
- This responsee0
- Direction
- did not occure0
- Comparator
- SNPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This response did not occur when SNP was replaced by ferricyanide”
t0“soybean (Glycine max) plants”
Claim · model-written summary
NOS inhibitors prevented elicitor-induced phytoalexin accumulation.
- Taxon
- soybeanGlycine maxt0
- Treatment
- NO synthase (NOS) inhibitorse0
- Interactor
- fungale0pathogen
- Outcome
- Phytoalexin accumulation induced by the fungal elicitore0
- Direction
- preventede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors”
t0“soybean (Glycine max) plants”
Claim · model-written summary
NOS inhibitors did not prevent SNP-induced phytoalexin accumulation.
- Taxon
- soybeanGlycine maxt0
- Treatment
- NO synthase (NOS) inhibitorse0
- Outcome
- Phytoalexin accumulatione0
- Comparator
- SNPe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phytoalexin accumulation induced by the fungal elicitor, but not by SNP, was prevented when cotyledons were pretreated with NO synthase (NOS) inhibitors”
t0“soybean (Glycine max) plants”
Claim · model-written summary
The fungal elicitor induced NOS activity near the inoculation site.
- Taxon
- soybeanGlycine maxe0
- Treatment
- Dpm elicitore0
- Interactor
- Dpme0pathogen
- Outcome
- NOS activitye0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The Dpm elicitor also induced NOS activity in soybean tissues proximal to the site of inoculation”
Claim · model-written summary
Induced NOS activity depended on calcium and NADPH and was sensitive to three NOS inhibitors.
- Taxon
- soybeanGlycine maxt0
- Gene
- NOSe0
- Outcome
- induced NOS activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The induced NOS activity was Ca(2+)- and NADPH-dependent and was sensitive to the NOS inhibitors N(G)-nitro-L-arginine methyl ester, aminoguanidine, and L-N(6)-(iminoethyl) lysine”
t0“soybean (Glycine max) plants”
Claim · model-written summary
SNP-elicited tissues showed no NOS activity.
- Taxon
- soybeanGlycine maxt0
- Treatment
- SNPe0
- Outcome
- NOS activity was not observede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NOS activity was not observed in SNP-elicited tissues”
t0“soybean (Glycine max) plants”
Claim · model-written summary
An anti-brain-NOS antibody labeled a 166-kD protein in elicited and nonelicited cotyledons.
- Taxon
- soybeanGlycine maxt0
- Gene
- brain NOSe0
- Outcome
- labeled a 166-kD proteine0
- Value
- 166-kDe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An antibody to brain NOS labeled a 166-kD protein in elicited and nonelicited cotyledons”
t0“soybean (Glycine max) plants”
Claim · model-written summary
Daidzein, genistein and glyceollins were identified after elicitor or SNP exposure.
- Taxon
- soybeanGlycine maxt0
- Treatment
- elicitor or SNPe0
- Outcome
- daidzein and genistein), pterocarpans (glyceollinse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Isoflavones (daidzein and genistein), pterocarpans (glyceollins), and flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP”
t0“soybean (Glycine max) plants”
Claim · model-written summary
Apigenin and luteolin were identified after elicitor or SNP exposure.
- Taxon
- soybeanGlycine maxt0
- Treatment
- elicitor or SNPe0
- Outcome
- apigenin and luteoline0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“flavones (apigenin and luteolin) were identified after exposure to the elicitor or SNP”
t0“soybean (Glycine max) plants”
Claim · model-written summary
Glyceollin and apigenin accumulation was limited under SNP versus fungal elicitor.
- Taxon
- soybeanGlycine maxt0
- Treatment
- SNP-elicitede0
- Outcome
- accumulation of glyceollins and apigenine0
- Direction
- limitede0
- Comparator
- fungal-elicited cotyledonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the accumulation of glyceollins and apigenin was limited in SNP-elicited compared with fungal-elicited cotyledons”
t0“soybean (Glycine max) plants”
Claim · model-written summary
NOS activity preceded flavonoid accumulation after fungal elicitor treatment.
- Taxon
- soybeanGlycine maxt0
- Treatment
- Dpm elicitore0
- Interactor
- Dpme0pathogen
- Outcome
- NOS activity preceded the accumulation of these flavonoidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NOS activity preceded the accumulation of these flavonoids in tissues treated with the Dpm elicitor”
t0“soybean (Glycine max) plants”
Claim · model-written summary
Metabolite accumulation was faster after SNP than fungal elicitor treatment.
- Taxon
- soybeanGlycine maxt0
- Treatment
- SNP-elicitede0
- Outcome
- accumulation of these metabolitese0
- Direction
- fastere0
- Comparator
- fungal-elicited cotyledonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The accumulation of these metabolites was faster in SNP-elicited than in fungal-elicited cotyledons”
t0“soybean (Glycine max) plants”
Claim · model-written summary
Authors infer that a constitutive NOS-like enzyme produces NO that triggers antimicrobial flavonoid biosynthesis after elicitation.
- Taxon
- soybeanGlycine maxe0
- Interactor
- Dpme0pathogen
- Gene
- NOS-like enzymee0
- Outcome
- biosynthesis of antimicrobial flavonoidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“response of soybean cotyledons to Dpm elicitor involves NO formation via a constitutive NOS-like enzyme that triggers the biosynthesis of antimicrobial flavonoids”
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See all 19 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.