nectriapyrone

CHEBI:142639 EXACT SEEDED

What these status tags mean

Curation status describes a workflow state. SEEDED means the record entered through the source-seeding workflow; it does not imply that no later curation occurred. PROPOSED marks an addition awaiting review; REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record. These are workflow decisions, not independently verified human review. Agent-assisted contributions may appear in the record history.

Grounding describes the identifier mapping: EXACT uses an ontology identity asserted by the source; MINTED keeps a local identifier when no defensible ontology identity is available; REVIEW_NEEDED flags an exact structure whose ontology identity needs adjudication. The grounding note retains any unresolved alternatives. These tags do not establish the strength of producer or activity evidence.

A member of the class of nectriapyrones that is pyran-2-one which is substituted at positions 3, 4, and 6 by methyl, methoxy, and but-2-en-2-yl groups, respectively in which the butenyl substituent has E configuration. A fungal metabolite that has been induced in the rice blast fungus Pyricularia oryzae by overexpression of a polyketide synthase gene (NEC1) and an O-methyltransferase gene (NEC2).

Structure

Standard InChIKey	NRLCQITWKJENAT-FNORWQNLSA-N
SMILES	C/C=C(\C)C1=CC(OC)=C(C)C(=O)O1
Stereochemistry	fully defined
Cross-references	npatlas:NPA033440, pubchem:5358550

Filing pathway

Polyketides — computed by NPClassifier npclassifier.gnps2.org@2026-09-07, which is why it is pinned rather than recomputed. The gene cluster's asserted class is pks, from MIBiG.

Producer organisms 1

A claim that this taxon makes the compound. The basis says what the evidence addressed — a knockout and a database assertion are not the same claim.

Taxon	Basis	Cluster	Evidence
Pyricularia oryzae 70-15 NCBITaxon:242507	BGC_CHARACTERIZED	mibig:BGC0002155	DOI:10.1016/s0040-4039(00)72224-6

Occurrences 3

Somebody found the compound in this organism and cited it. That is not a claim that the organism makes it, and nothing here promotes one to the other.

Taxon	Source	Reference
Magnaporthe oryzae NCBITaxon:318829	CHEBI	PMID:30443971
Nalanthamala vermoesenii NCBITaxon:64489	LOTUS	DOI:10.1016/0031-9422(92)80225-4
Nalanthamala vermoesenii NCBITaxon:64489	LOTUS	DOI:10.1016/0031-9422(92)83704-3

Biosynthetic gene clusters 1

Accession	Host	Locus evidence	Genome
mibig:BGC0002155	Pyricularia oryzae 70-15 NCBITaxon:242507	CLUSTER_DEMONSTRATED	genbank:CM001235.1

A locus claim and a taxon claim are different questions. Heterologous expression settles the first and leaves the second where the isolation report left it.

Biosynthesis curated

Written by a curator with claim-level evidence on each step; not derived from a source. This is what the rest of the record exists to support.

Step	Enzyme	Reaction	Substrate → product	Evidence
1	NEC2 O-methyltransferase UniProtKB:G4NEA9	RHEA:58748	CHEBI:142640 → CHEBI:142639	DOI:10.1002/cbic.201800620

Step 1: NEC2 methylates desmethylnectriapyrone to the 4-O-methyl 2-pyrone nectriapyrone; this single step records the NEC2/RHEA:58748 tailoring reaction and leaves upstream NEC1 polyketide assembly and downstream hydrolysis to nectriapyrone D unexpanded.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 3 nodes, 2 edges

Pyricularia oryzae 70-15 NEC2 O-methylates desmethylnectriapyrone to form nectriapyrone.

Subject	Predicate	Object	Notes	Evidence
desmethylnectriapyrone	is O-methylated by	NEC2	NEC2 uses SAM to methylate the desmethylnectriapyrone oxygen and RHEA records this step as RHEA:58748.	DOI:10.1002/cbic.201800620 https://mibig.secondarymetabolites.org/repository/BGC0002155.3/BGC0002155.gbk https://www.uniprot.org/uniprotkb/G4NEA9 https://www.rhea-db.org/rhea/58748 reference DOI:10.1002/cbic.201800620 evidence type PRIMARY_EXPERIMENT snippet The nectriapyrone biosynthetic gene cluster consists of a polyketide synthase gene (NEC1) and an O-methyltransferase gene (NEC2). notes Motoyama et al. assigned the Pyricularia oryzae 70-15 nectriapyrone cluster and showed that NEC1 plus NEC2 overexpression induced overproduction of nectriapyrone and nectriapyrone analogues. reference https://mibig.secondarymetabolites.org/repository/BGC0002155.3/BGC0002155.gbk evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes MIBiG BGC0002155.3 places NEC2 locus tag MGG_14657 at GenBank CM001235.1 with protein_id EHA48592.1 in the Pyricularia oryzae 70-15 nectriapyrone BGC. reference https://www.uniprot.org/uniprotkb/G4NEA9 evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes Reviewed UniProtKB:G4NEA9 resolves to the 265 aa Pyricularia oryzae strain 70-15 O-methyltransferase NEC2 / MGG_14657 gene product, cross-references EMBL CM001235 protein EHA48592.1, and annotates catalytic activity RHEA:58748. reference https://www.rhea-db.org/rhea/58748 evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes RHEA:58748 is the desmethylnectriapyrone plus S-adenosyl-L-methionine to nectriapyrone plus S-adenosyl-L-homocysteine plus H(+) reaction; Rhea maps the master reaction to UniProtKB:G4NEA9 in Swiss-Prot.
NEC2	forms	nectriapyrone	NEC2 is the MGG_14657 O-methyltransferase in the BGC0002155 Pyricularia oryzae 70-15 cluster.	DOI:10.1002/cbic.201800620 https://mibig.secondarymetabolites.org/repository/BGC0002155.3/BGC0002155.gbk https://www.uniprot.org/uniprotkb/G4NEA9 https://www.rhea-db.org/rhea/58748 reference DOI:10.1002/cbic.201800620 evidence type PRIMARY_EXPERIMENT snippet The nectriapyrone biosynthetic gene cluster consists of a polyketide synthase gene (NEC1) and an O-methyltransferase gene (NEC2). notes Motoyama et al. assigned the Pyricularia oryzae 70-15 nectriapyrone cluster and showed that NEC1 plus NEC2 overexpression induced overproduction of nectriapyrone and nectriapyrone analogues. reference https://mibig.secondarymetabolites.org/repository/BGC0002155.3/BGC0002155.gbk evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes MIBiG BGC0002155.3 places NEC2 locus tag MGG_14657 at GenBank CM001235.1 with protein_id EHA48592.1 in the Pyricularia oryzae 70-15 nectriapyrone BGC. reference https://www.uniprot.org/uniprotkb/G4NEA9 evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes Reviewed UniProtKB:G4NEA9 resolves to the 265 aa Pyricularia oryzae strain 70-15 O-methyltransferase NEC2 / MGG_14657 gene product, cross-references EMBL CM001235 protein EHA48592.1, and annotates catalytic activity RHEA:58748. reference https://www.rhea-db.org/rhea/58748 evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes RHEA:58748 is the desmethylnectriapyrone plus S-adenosyl-L-methionine to nectriapyrone plus S-adenosyl-L-homocysteine plus H(+) reaction; Rhea maps the master reaction to UniProtKB:G4NEA9 in Swiss-Prot.

Every edge carries its own citation; an uncited edge is refused by the corpus tests.

Explore across X-Mech

AntibioticMech (nectriapyrone) ↗ MediaIngredientMech (CHEBI:142639) ↗ TaxonMech: Pyricularia oryzae 70-15 (NCBITaxon:242507) ↗ PathwayMech (mibig:BGC0002155) ↗

Provenance

Source concept	Source	Version
BGC0002155	MIBIG	3
CHEBI:142639	CHEBI	3-star

This page is generated from data/natural_products/polyketides/nectriapyrone.yaml, which is generated from the committed inventories. Neither is edited by hand.