Abstract
Isochorismate-derived metabolism enables biosynthesis of the plant defense hormone salicylic acid (SA) and its derivatives. In Arabidopsis thaliana, the stress-induced accumulation of SA depends on ISOCHORISMATE SYNTHASE1 (ICS1) and also requires the presumed isochorismate transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5) and the GH3 enzyme avrPphB SUSCEPTIBLE3 (PBS3). By comparative metabolite and structural analyses, we identified several hitherto unreported ICS1- and EDS5-dependent, biotic stress-inducible Arabidopsis metabolites. These involve meta-substituted SA derivatives (5-formyl-SA, 5-carboxy-SA, 5-carboxymethyl-SA), their benzoic acid (BA) analogs (3-formyl-BA, 3-carboxy-BA, 3-carboxymethyl-BA), and besides the previously detected salicyloyl-aspartate (SA-Asp), the ester conjugate salicyloyl-malate (SA-Mal). SA functions as a biosynthetic precursor for SA-Mal and SA-Asp, but not for the meta-substituted SA- and BA-derivatives, which accumulate to moderate levels at later stages of bacterial infection. Interestingly, Arabidopsis leaves possess oxidizing activity to effectively convert meta-formyl- into meta-carboxy-SA/BAs. In contrast to SA, exogenously applied meta-substituted SA/BA-derivatives and SA-Mal exert a moderate impact on plant immunity and defence-related gene expression. While the isochorismate-derived metabolites are negatively regulated by the SA receptor NON-EXPRESSOR OF PR GENES1, SA conjugates (SA-Mal, SA-Asp, SA-glucose conjugates) and meta-substituted SA/BA-derivatives are oppositely affected by PBS3. Notably, our data indicate a PBS3-independent path to isochorismate-derived SA at later stages of bacterial infection, which does not considerably impact immune-related characteristics. Moreover, our results argue against a previously proposed role of EDS5 in the biosynthesis of the immune signal N-hydroxypipecolic acid and associated transport processes. We propose a significantly extended biochemical scheme of plant isochorismate metabolism that involves an alternative generation mode for benzoate- and salicylate-derivatives.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 16
Claim · model-written summary
Several previously unreported ICS1- and EDS5-dependent Arabidopsis metabolites were identified.
- Taxon
- Arabidopsis
Arabidopsise0 - Gene
- ICS1- and EDS5-dependente0
- Outcome
- biotic stress-inducible Arabidopsis metabolitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we identified several hitherto unreported ICS1- and EDS5-dependent, biotic stress-inducible Arabidopsis metabolites”
Claim · model-written summary
The identified metabolites included meta-substituted salicylic acid derivatives.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- meta-substituted SA derivatives (5-formyl-SA, 5-carboxy-SA, 5-carboxymethyl-SA)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“meta-substituted SA derivatives (5-formyl-SA, 5-carboxy-SA, 5-carboxymethyl-SA)”
t0“In Arabidopsis thaliana”
Claim · model-written summary
The identified metabolites included three benzoic acid analogs.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- benzoic acid (BA) analogs (3-formyl-BA, 3-carboxy-BA, 3-carboxymethyl-BA)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“their benzoic acid (BA) analogs (3-formyl-BA, 3-carboxy-BA, 3-carboxymethyl-BA)”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Salicyloyl-malate was identified as an ester conjugate.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- ester conjugate salicyloyl-malate (SA-Mal)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ester conjugate salicyloyl-malate (SA-Mal)”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Salicylic acid was a biosynthetic precursor for SA-Mal and SA-Asp.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Compound
- SAe0
- Outcome
- SA-Mal and SA-Aspe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SA functions as a biosynthetic precursor for SA-Mal and SA-Asp”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Salicylic acid was not a precursor for the meta-substituted SA and BA derivatives.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Compound
- SAe0
- Outcome
- meta-substituted SA- and BA-derivativese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SA functions as a biosynthetic precursor for SA-Mal and SA-Asp, but not for the meta-substituted SA- and BA-derivatives”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Meta-substituted SA and BA derivatives accumulated moderately at later bacterial infection stages.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- meta-substituted SA- and BA-derivativese0
- Direction
- accumulatee0
- Qualifier
- later stages of bacterial infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“meta-substituted SA- and BA-derivatives, which accumulate to moderate levels at later stages of bacterial infection”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Arabidopsis leaves converted meta-formyl derivatives into meta-carboxy SA and BA derivatives.
- Taxon
- ArabidopsisArabidopsise0
- Organ / stage
- leavese0
- Outcome
- oxidizing activitye0
- Qualifier
- convert meta-formyl- into meta-carboxy-SA/BAse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Arabidopsis leaves possess oxidizing activity to effectively convert meta-formyl- into meta-carboxy-SA/BAs”
Claim · model-written summary
Applied meta-substituted derivatives and SA-Mal moderately affected immunity.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Treatment
- exogenously applied meta-substituted SA/BA-derivatives and SA-Male0
- Outcome
- plant immunitye0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenously applied meta-substituted SA/BA-derivatives and SA-Mal exert a moderate impact on plant immunity”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Applied meta-substituted derivatives and SA-Mal moderately affected defence gene expression.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Treatment
- exogenously applied meta-substituted SA/BA-derivatives and SA-Male0
- Outcome
- defence-related gene expressione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenously applied meta-substituted SA/BA-derivatives and SA-Mal exert a moderate impact on plant immunity and defence-related gene expression”
t0“In Arabidopsis thaliana”
Claim · model-written summary
NON-EXPRESSOR OF PR GENES1 negatively regulated isochorismate-derived metabolites.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- NON-EXPRESSOR OF PR GENES1e0
- Outcome
- isochorismate-derived metabolitese0
- Direction
- negatively regulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the isochorismate-derived metabolites are negatively regulated by the SA receptor NON-EXPRESSOR OF PR GENES1”
t0“In Arabidopsis thaliana”
Claim · model-written summary
PBS3 affected SA conjugates and meta-substituted derivatives in opposite directions.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- PBS3e0
- Outcome
- SA conjugates (SA-Mal, SA-Asp, SA-glucose conjugates) and meta-substituted SA/BA-derivativese0
- Direction
- oppositely affectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SA conjugates (SA-Mal, SA-Asp, SA-glucose conjugates) and meta-substituted SA/BA-derivatives are oppositely affected by PBS3”
t0“In Arabidopsis thaliana”
Claim · model-written summary
A PBS3-independent route to isochorismate-derived SA operated late in bacterial infection.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- PBS3e0
- Outcome
- isochorismate-derived SAe0
- Qualifier
- later stages of bacterial infectione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a PBS3-independent path to isochorismate-derived SA at later stages of bacterial infection”
t0“In Arabidopsis thaliana”
Claim · model-written summary
That route had little impact on immune-related characteristics.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- immune-related characteristicse0
- Direction
- does not considerably impacte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“which does not considerably impact immune-related characteristics”
t0“In Arabidopsis thaliana”
Claim · model-written summary
Results argued against an EDS5 role in N-hydroxypipecolic acid biosynthesis and transport.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- EDS5e0
- Outcome
- biosynthesis of the immune signal N-hydroxypipecolic acid and associated transport processese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“our results argue against a previously proposed role of EDS5 in the biosynthesis of the immune signal N-hydroxypipecolic acid and associated transport processes”
t0“In Arabidopsis thaliana”
Claim · model-written summary
The authors proposed an extended isochorismate scheme with another route to benzoate and salicylate derivatives.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Outcome
- benzoate- and salicylate-derivativese0
- Qualifier
- alternative generation modee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We propose a significantly extended biochemical scheme of plant isochorismate metabolism that involves an alternative generation mode for benzoate- and salicylate-derivatives”
t0“In Arabidopsis thaliana”