id: Q9SIV0 gene_symbol: SUR1 product_type: PROTEIN status: COMPLETE taxon: id: NCBITaxon:3702 label: Arabidopsis thaliana description: SUR1 (SUPERROOT1; also ALF1/HLS3/RTY1, At2g20610) is the pyridoxal 5'-phosphate-dependent C-S lyase of core glucosinolate biosynthesis. It belongs to the class-I (tyrosine aminotransferase-like) fold of PLP enzymes but has diverged to cleave the C-S bond of S-(alkylacetohydroximoyl)-L-cysteine conjugates, derived from the glutathione conjugates of aldoxime-derived aci-nitro/nitrile oxide intermediates, releasing the thiohydroximate that UGT74 enzymes then S-glucosylate. It is a major cytosolic enzyme of the Arabidopsis pathway. Loss-of-function mutants accumulate C-S lyase substrates and have severe glucosinolate defects, but residual indolic glucosinolate formation demonstrates additional C-S lyase capacity. Because indole-3-acetaldoxime is then shunted into indole-3-acetic acid, sur1 mutants overproduce auxin and show the pleiotropic "superroot" phenotype (excess adventitious and lateral roots, epinastic cotyledons, no apical hook, sterility), so SUR1 indirectly buffers auxin homeostasis at the IAOx branch point. alternative_products: - name: '1' id: Q9SIV0-1 - name: '2' id: Q9SIV0-2 sequence_note: VSP_041760, VSP_041761 existing_annotations: - term: id: GO:0001560 label: regulation of cell growth by extracellular stimulus evidence_type: IMP original_reference_id: PMID:15851402 qualifier: acts_upstream_of_or_within review: summary: Hypocotyl growth study in which sur1 (hls3) was used as an auxin-overproducing mutant to analyse auxin/ethylene/brassinosteroid interactions in hypocotyl elongation and apical hook formation. action: MARK_AS_OVER_ANNOTATED reason: The growth effect of sur1 is a downstream consequence of IAA overproduction after IAOx is diverted from the blocked glucosinolate pathway; SUR1 does not execute any step of growth regulation by an extracellular stimulus. The phenotype is real (abstract-only cache, so not removed) but does not describe SUR1 function. supported_by: - reference_id: PMID:15851402 supporting_text: our results indicate that HLS1, SUR1/HLS3/RTY1/ALF1 and AMP1/HPT/COP2/HLS2/PT act on the auxin-ethylene interaction - reference_id: PMID:14871316 supporting_text: This suggests that the "high-auxin" phenotype of sur1 is caused by accumulation of endogenous C-S lyase substrates as well as aldoximes, including indole-3-acetaldoxime (IAOx) that is channeled into the main auxin indole-3-acetic acid (IAA). - term: id: GO:0004838 label: L-tyrosine:2-oxoglutarate transaminase activity evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: enables supporting_entities: - AGI_LocusCode:AT5G36160 - AGI_LocusCode:AT5G53970 - FB:FBgn0030558 - MGI:MGI:98487 - PANTHER:PTN000202983 - RGD:3820 - UniProtKB:P17735 - WB:WBGene00009628 review: summary: Tyrosine aminotransferase activity propagated from the PTN000202983 node of the PTHR45744 tyrosine aminotransferase family (donors include human TAT and Arabidopsis TAT7/AT5G53970). SUR1 sits in its own subfamily (PTHR45744:SF15, S-alkyl-thiohydroximate lyase SUR1). action: MARK_AS_OVER_ANNOTATED reason: SUR1 has neofunctionalized to a C-S lyase acting on S-alkylthiohydroximate cysteine conjugates; no tyrosine transaminase activity has been reported for SUR1, and the closely related SUR1-like C-S lyase from Taraxacum showed no in vitro TyrAT activity. Residual transamination by this PLP fold cannot be excluded (the Taraxacum homolog has alanine aminotransferase activity), so this is marked as over-annotation rather than removed. propagation_review: root_cause: PROPAGATION_BAD failure_modes: - FUNCTIONAL_DIVERGENCE source_entities: - source_id: PANTHER:PTN000202983 source_label: PTN000202983 source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: Tyrosine aminotransferase function is well supported for the donor TATs (human TAT, Arabidopsis TAT7), but SUR1 lies in the neofunctionalized SUR1 subfamily (PTHR45744:SF15) with demonstrated C-S lyase activity and no reported TAT activity. supported_by: - reference_id: PMID:23073363 supporting_text: It is homologous to tyrosine and alanine aminotransferases (AlaATs) as well as to an Arabidopsis thaliana carbon-sulfur lyase (C-S lyase) (SUR1) - reference_id: PMID:23073363 supporting_text: However, we detected no in vitro tyrosine aminotransferase (TyrAT) activity - reference_id: PMID:14871316 supporting_text: We report characterization of SUPERROOT1 (SUR1) as the C-S lyase in glucosinolate biosynthesis. - term: id: GO:0005515 label: protein binding evidence_type: IPI original_reference_id: PMID:32612234 qualifier: enables supporting_entities: - UniProtKB:F4K773 review: summary: Binary Y2H interaction with At5g37478 (F4K773) from a systems-level phytohormone interactome map. action: REMOVE reason: Generic protein binding is uninformative about SUR1 function; no functional consequence of the interaction is known. Removal does not imply the interaction is false. supported_by: - reference_id: PMID:32612234 supporting_text: we experimentally generated a systems-level map of the Arabidopsis phytohormone signalling network, consisting of more than 2,000 binary protein-protein interactions - term: id: GO:0005737 label: cytoplasm evidence_type: ISM original_reference_id: GO_REF:0000122 qualifier: located_in review: summary: The supported cytoplasmic compartment is the cytosol. action: MODIFY reason: Refine the true general cytoplasm location to cytosol, already supported elsewhere in this review. This refinement does not exclude distinct secondary compartments reported under other terms. supported_by: - reference_id: PMID:25293756 supporting_text: Applying this approach to the crude cytosolic fraction of Arabidopsis thaliana leaves using size exclusion chromatography, we identified hundreds of cytosolic proteins proposed_replacement_terms: - id: GO:0005829 label: cytosol - term: id: GO:0005739 label: mitochondrion evidence_type: HDA original_reference_id: PMID:28887381 qualifier: located_in review: summary: The microsome experiment does not independently establish mitochondrion localization. action: MARK_AS_OVER_ANNOTATED reason: Full-text inspection of PMID:28887381 shows that washed microsomes were profiled by chromatography and sucrose gradients, while subcellular labels were taken from SUBAcon and prior GFP data. The authors explicitly report that no organelle occupied a single gradient cluster. Detection or membrane association is meaningful, but assigning SUR1 specifically to mitochondrion exceeds the spatial resolution of this experiment. This is not a claim that the detected protein is absent or that all additional localization is impossible; the unsupported compartment assignment, rather than the proteomic observation, is marked as over-annotated. supported_by: - reference_id: PMID:28887381 supporting_text: The proteins with known localizations had scattered distributions across the entire gradient and no organelle fell in a single cluster. - reference_id: PMID:28887381 supporting_text: We used SUBAcon localization predictions to analyze oligomerization as a function of subcellular localization (Fig. 7C). - term: id: GO:0005829 label: cytosol evidence_type: HDA original_reference_id: PMID:25293756 qualifier: located_in review: summary: Detected in size-exclusion profiling of the crude leaf cytosolic fraction. action: ACCEPT reason: Consistent with the cytosolic location of the core glucosinolate pathway and with the IBA; cytosol is the location of SUR1 activity. supported_by: - reference_id: PMID:25293756 supporting_text: Applying this approach to the crude cytosolic fraction of Arabidopsis thaliana leaves using size exclusion chromatography, we identified hundreds of cytosolic proteins - term: id: GO:0005829 label: cytosol evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: is_active_in supporting_entities: - AGI_LocusCode:AT5G36160 - PANTHER:PTN005243493 review: summary: Phylogenetic inference of cytosolic activity within the plant TAT/SUR1 clade. action: ACCEPT reason: Consistent with the HDA cytosol data and with cytosolic localization of the Taraxacum SUR1 homolog. supported_by: - reference_id: PMID:23073363 supporting_text: TbCSL is in vivo localized in the cytosol - term: id: GO:0006520 label: amino acid metabolic process evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: involved_in supporting_entities: - InterPro:IPR005958 review: summary: InterPro2GO mapping from the tyrosine/nicotianamine aminotransferase signature (IPR005958). action: MARK_AS_OVER_ANNOTATED reason: The mapping reflects the ancestral aminotransferase family, not SUR1's role. SUR1 cleaves S-substituted cysteine conjugates in glucosinolate biosynthesis; this is better described by glucosinolate biosynthetic process. supported_by: - reference_id: PMID:14871316 supporting_text: We report characterization of SUPERROOT1 (SUR1) as the C-S lyase in glucosinolate biosynthesis. - term: id: GO:0006572 label: L-tyrosine catabolic process evidence_type: IBA original_reference_id: GO_REF:0000033 qualifier: involved_in supporting_entities: - AGI_LocusCode:AT5G36160 - AGI_LocusCode:AT5G53970 - FB:FBgn0030558 - MGI:MGI:98487 - PANTHER:PTN000202983 - UniProtKB:P17735 review: summary: A tyrosine-catabolic role is not established for specialized glucosinolate C-S lyase SUR1. action: MARK_AS_OVER_ANNOTATED reason: The target has a directly demonstrated glucosinolate-pathway role, whereas the inherited tyrosine-catabolism claim relies on its broader PLP-enzyme lineage. Comparator Taraxacum assays do not establish loss of every possible transaminase activity in Arabidopsis SUR1. Retain this as an unsupported physiological extension, without claiming that lack of a reported phenotype proves evolutionary loss. propagation_review: root_cause: PROPAGATION_BAD failure_modes: - FUNCTIONAL_DIVERGENCE source_entities: - source_id: PANTHER:PTN000202983 source_label: PTN000202983 source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: Tyrosine aminotransferase function is well supported for the donor TATs (human TAT, Arabidopsis TAT7), but SUR1 lies in the neofunctionalized SUR1 subfamily (PTHR45744:SF15) with demonstrated C-S lyase activity and no reported TAT activity. supported_by: - reference_id: PMID:14871316 supporting_text: The abolishment of glucosinolates in sur1 indicates that the SUR1 function is not redundant and thus SUR1 constitutes a single gene family. - reference_id: PMID:23073363 supporting_text: However, we detected no in vitro tyrosine aminotransferase (TyrAT) activity - term: id: GO:0008483 label: transaminase activity evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables supporting_entities: - InterPro:IPR005958 review: summary: InterPro2GO transfer of transaminase activity from the aminotransferase fold signature. action: MODIFY reason: The essence (a PLP-dependent enzyme of the aminotransferase fold) is right, but SUR1's demonstrated activity is C-S bond cleavage of S-alkylthiohydroximate cysteine conjugates; the informative term is S-alkylthiohydroximate lyase activity. proposed_replacement_terms: - id: GO:0080108 label: S-alkylthiohydroximate lyase activity supported_by: - reference_id: PMID:14871316 supporting_text: C-S lyase activity of recombinant SUR1 heterologously expressed in Escherichia coli was demonstrated using the C-S lyase substrate djenkolic acid. - term: id: GO:0009684 label: indoleacetic acid biosynthetic process evidence_type: IMP original_reference_id: PMID:8589625 qualifier: acts_upstream_of_or_within review: summary: sur1 mutants have elevated free and conjugated IAA and an auxin-overproduction phenotype. action: MARK_AS_OVER_ANNOTATED reason: SUR1 performs no step of IAA biosynthesis; loss of SUR1 increases IAA because the upstream glucosinolate intermediate IAOx is redirected into auxin. The mutant phenotype therefore reflects metabolic shunting (SUR1 acting, if anything, to limit IAA production), not participation. Abstract-only cache and experimental code, so marked as over-annotation rather than removed. supported_by: - reference_id: PMID:8589625 supporting_text: Analysis by gas chromatography coupled to mass spectrometry indicated increased levels of both free and conjugated indole-3-acetic acid. - reference_id: PMID:14871316 supporting_text: This suggests that the "high-auxin" phenotype of sur1 is caused by accumulation of endogenous C-S lyase substrates as well as aldoximes, including indole-3-acetaldoxime (IAOx) that is channeled into the main auxin indole-3-acetic acid (IAA). - term: id: GO:0016846 label: carbon-sulfur lyase activity evidence_type: IDA original_reference_id: PMID:14871316 qualifier: enables review: summary: SUR1 is the substrate-specific S-alkylthiohydroximate C-S lyase. action: MODIFY reason: Refine the general carbon-sulfur lyase class to the specific activity already annotated. The original study combines in vivo labeled-precursor accumulation with recombinant C-S lyase activity on djenkolic acid; it is not represented as a purified native Cys-Gly-conjugate assay. supported_by: - reference_id: PMID:14871316 supporting_text: C-S lyase activity of recombinant SUR1 heterologously expressed in Escherichia coli was demonstrated using the C-S lyase substrate djenkolic acid. proposed_replacement_terms: - id: GO:0080108 label: S-alkylthiohydroximate lyase activity - term: id: GO:0019761 label: glucosinolate biosynthetic process evidence_type: IMP original_reference_id: PMID:14871316 qualifier: acts_upstream_of_or_within review: summary: sur1 is completely devoid of aliphatic and indole glucosinolates, and in vivo feeding of p-hydroxyphenylacetaldoxime leads to accumulation of the C-S lyase substrate. action: ACCEPT reason: Core process; SUR1 catalyzes the C-S cleavage step of the core glucosinolate pathway. A recent report that sur1 retains some indolic glucosinolate suggests a minor additional C-S lyase for indolic substrates, but does not alter SUR1's role. supported_by: - reference_id: PMID:14871316 supporting_text: This is evidenced by selective metabolite profiling of sur1, which is completely devoid of aliphatic and indole glucosinolates. - reference_id: PMID:41819465 supporting_text: sur1 plants are still able to accumulate significant indolic GL amounts as compared with wild type plants, indicating that additional C-S lyase is involved in the biosynthesis of these specialized metabolites - term: id: GO:0030170 label: pyridoxal phosphate binding evidence_type: IEA original_reference_id: GO_REF:0000002 qualifier: enables supporting_entities: - InterPro:IPR004839 - InterPro:IPR005958 review: summary: PLP binding inferred from the class-I aminotransferase domain; UniProt records PLP as cofactor. action: ACCEPT reason: C-S lyases of this fold are PLP-dependent; cofactor binding is correct and mechanistically required, though not a standalone function. supported_by: - reference_id: PMID:23073363 supporting_text: We isolated a novel pyridoxal-5-phosphate-dependent l-cystine lyase from the dandelion Taraxacum brevicorniculatum. - term: id: GO:0048830 label: adventitious root development evidence_type: TAS original_reference_id: PMID:16377752 qualifier: acts_upstream_of_or_within review: summary: Proteomic comparison of sur1-3 and other adventitious-rooting mutants; sur1 spontaneously forms adventitious roots because it overproduces auxin. action: MARK_AS_OVER_ANNOTATED reason: Excess adventitious rooting is an indirect consequence of auxin overproduction in the absence of SUR1's glucosinolate-pathway activity; SUR1 does not function in root development per se. supported_by: - reference_id: PMID:16377752 supporting_text: The auxin overproducers sur1-3 and sur2-1 spontaneously develop adventitious roots on the hypocotyl - reference_id: PMID:14871316 supporting_text: This suggests that the "high-auxin" phenotype of sur1 is caused by accumulation of endogenous C-S lyase substrates - term: id: GO:0050832 label: defense response to fungus evidence_type: IDA original_reference_id: PMID:32213638 qualifier: acts_upstream_of_or_within review: summary: The cited paper (Liu et al. 2020, ODR1/bHLH57 control of ABA biosynthesis and seed dormancy) is about seed dormancy. Its full text (PMC7268807, now cached locally via the publication pipeline as publications/PMID_32213638.md, HTML extraction) does not mention SUR1/SUPERROOT1, At2g20610, glucosinolates, fungi or any pathogen assay. action: REMOVE reason: This is not a case of an abstract foregrounding another gene. The whole cached article (Results, Methods and the accession-number list) contains no SUR1 genotype and no fungal or defense experiment, so it cannot support an IDA for defense response to fungus. The Accession Numbers section lists every gene studied (ODR1, ABI3, bHLH57, NCEDs, CYP707As, ABI4, DREB2C, TTG1, MYB5, DOG1, RDO5 and the PP2A reference) and At2g20610 is not among them. A QuickGO query for PMID:32213638 (recorded in SUR1-notes.md) returns this single annotation and nothing for ODR1 or bHLH57, which points to a mis-keyed reference in the TAIR record rather than a SUR1 experiment in the paper. The row is removed as unsupported by its reference. This does not deny that SUR1-dependent indole glucosinolates contribute to antifungal defense; that role would be indirect, via SUR1's metabolic products, and should be re-annotated from a paper that tests it. supported_by: - reference_id: PMID:32213638 supporting_text: we report the characterization of two ABA-related seed dormancy regulators in Arabidopsis - reference_id: PMID:32213638 supporting_text: 'Sequence data from this investigation can be found in the Arabidopsis Genome Initiative or GenBank/EMBL databases under the following accession numbers: ODR1 (At1g27461), ABI3 (At3g24650), bHLH57 (At4g01460), NCED2 (At4g18350) NCED3 (At3g14440), NCED5 (At1g30100), NCED6 (At3g24220), NCED9 (At1g78390), CYP707A1 (At4g19230), CYP707A2 (At2g29090), CYP707A3 (At5g45340), CYP707A4 (At3g19270), ABI4 (At2g40220), DREB2C (At2g40340), TTG1 (At5g24520), MYB5 (At3g13540), DOG1 (At5g45830), RDO5 (At4g11040), and PP2A (At1g13320).' source_defects: - defect_type: WRONG_REFERENCE resource: TAIR slot: DB:Reference requested_change: CHECK asserted_value: PMID:32213638 cause: UNKNOWN confidence: CONFIRMED explanation: This SUR1 (At2g20610, Q9SIV0) IDA for defense response to fungus (GO:0050832) is keyed to PMID:32213638 (Liu et al. 2020, ODR1/bHLH57 and seed dormancy). The full text (PMC7268807) contains no SUR1 genotype and no fungal or pathogen assay. Its accession list omits At2g20610, and QuickGO shows this as the paper's only annotation. The reference appears to be mis-keyed. Please identify the intended paper, or delete the row. supported_by: - reference_id: PMID:32213638 supporting_text: we report the characterization of two ABA-related seed dormancy regulators in Arabidopsis - term: id: GO:0080108 label: S-alkylthiohydroximate lyase activity evidence_type: IMP original_reference_id: PMID:14871316 qualifier: enables review: summary: Core molecular function. sur1 accumulates the C-S lyase substrate after feeding labeled p-hydroxyphenylacetaldoxime, lacks glucosinolates, and recombinant SUR1 has C-S lyase activity. action: ACCEPT reason: Combined in vivo substrate accumulation and in vitro C-S lyase activity establish SUR1 as the S-alkylthiohydroximate C-S lyase of glucosinolate biosynthesis. supported_by: - reference_id: PMID:14871316 supporting_text: Furthermore, following in vivo feeding with radiolabeled p-hydroxyphenylacetaldoxime to the sur1 mutant, the corresponding C-S lyase substrate accumulated. core_functions: - description: PLP-dependent S-alkylthiohydroximate C-S lyase in glucosinolate core formation, producing thiohydroximates downstream of glutathione-conjugate processing. Its assignment combines in vivo precursor accumulation with recombinant model-substrate C-S lyase activity; the exact native Cys-Gly versus cysteine-conjugate substrate handoff remains qualified. SUR1 is a major pathway enzyme, but residual indolic glucosinolates in sur1 mutants demonstrate additional C-S lyase capacity. molecular_function: id: GO:0080108 label: S-alkylthiohydroximate lyase activity directly_involved_in: - id: GO:0019761 label: glucosinolate biosynthetic process locations: - id: GO:0005829 label: cytosol supported_by: - reference_id: PMID:14871316 supporting_text: We report characterization of SUPERROOT1 (SUR1) as the C-S lyase in glucosinolate biosynthesis. - reference_id: PMID:14871316 supporting_text: C-S lyase activity of recombinant SUR1 heterologously expressed in Escherichia coli was demonstrated using the C-S lyase substrate djenkolic acid. - reference_id: PMID:21712415 - reference_id: PMID:41819465 references: - id: GO_REF:0000002 title: Gene Ontology annotation through association of InterPro records with GO terms findings: - statement: InterPro2GO transfers aminotransferase-family terms (transaminase activity, amino acid metabolism) and PLP binding; only PLP binding reflects SUR1's actual biochemistry. - id: GO_REF:0000033 title: Annotation inferences using phylogenetic trees findings: - statement: PAINT IBA from the tyrosine aminotransferase node transfers TAT activity and tyrosine catabolism to SUR1, a neofunctionalized C-S lyase subfamily member; cytosol IBA is appropriate. - id: GO_REF:0000122 title: AtSubP analysis findings: - statement: Predicts cytoplasmic localization. - id: PMID:14871316 title: Arabidopsis mutants in the C-S lyase of glucosinolate biosynthesis establish a critical role for indole-3-acetaldoxime in auxin homeostasis. findings: - statement: SUR1 is the glucosinolate C-S lyase; sur1 lacks aliphatic and indole glucosinolates, accumulates C-S lyase substrate, and its high-auxin phenotype arises from IAOx diversion into IAA. supporting_text: We report characterization of SUPERROOT1 (SUR1) as the C-S lyase in glucosinolate biosynthesis. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Abstract-only cache; defining paper for SUR1 function. - id: PMID:15851402 title: 'Auxin, ethylene and brassinosteroids: tripartite control of growth in the Arabidopsis hypocotyl.' findings: - statement: Uses sur1/hls3 among hormone mutants to dissect hypocotyl growth; relevant only to the indirect auxin phenotype. reference_review: relevance: LOW correctness: VERIFIED review_notes: Abstract-only; source of the growth-regulation IMP. - id: PMID:16377752 title: Proteomic analysis of different mutant genotypes of Arabidopsis led to the identification of 11 proteins correlating with adventitious root development. findings: - statement: sur1-3 is used as an auxin overproducer that spontaneously forms adventitious roots. reference_review: relevance: LOW correctness: VERIFIED review_notes: Source of the TAS adventitious root development annotation; phenotype is indirect. - id: PMID:23073363 title: A novel C-S lyase from the latex-producing plant Taraxacum brevicorniculatum displays alanine aminotransferase and l-cystine lyase activity. findings: - statement: A SUR1-homologous PLP C-S lyase from Taraxacum is cytosolic, has L-cystine lyase and AlaAT but no TyrAT activity. supporting_text: However, we detected no in vitro tyrosine aminotransferase (TyrAT) activity reference_review: relevance: MEDIUM correctness: VERIFIED review_notes: Homolog evidence informing the aminotransferase-family IBA/IEA assessments. - id: PMID:25293756 title: A proteomic strategy for global analysis of plant protein complexes. findings: - statement: Detection in the crude leaf cytosolic fraction. reference_review: relevance: LOW correctness: VERIFIED review_notes: High-throughput localization dataset. - id: PMID:28887381 title: Global Analysis of Membrane-associated Protein Oligomerization Using Protein Correlation Profiling. findings: - statement: High-throughput membrane fraction profiling; source of HDA mitochondrion. reference_review: relevance: LOW correctness: VERIFIED review_notes: High-throughput localization dataset. - id: PMID:32213638 title: REVERSAL OF RDO5 1, a Homolog of Rice Seed Dormancy4, Interacts with bHLH57 and Controls ABA Biosynthesis and Seed Dormancy in Arabidopsis. findings: - statement: Seed dormancy/ABA paper; neither the abstract nor the cached full text mentions SUR1 or fungal defense, and At2g20610 is absent from its accession list. reference_review: relevance: NONE correctness: MISCITED review_notes: Full text cached (PMC7268807, HTML extraction, 2026-10-15). The paper is real and correctly identified, but it does not support the IDA defense response to fungus annotation keyed to it for SUR1; likely a mis-keyed reference in the TAIR record. - id: PMID:32612234 title: Extensive signal integration by the phytohormone protein network. findings: - statement: Large-scale Y2H phytohormone interactome; source of the protein binding IPI. reference_review: relevance: LOW correctness: VERIFIED review_notes: Interaction only; no functional consequence for SUR1. - id: PMID:41819465 title: SUPERROOT1 is not the only C-S lyase capable to contribute to glucosinolate biosynthesis in Arabidopsis thaliana. findings: - statement: sur1 retains significant indolic glucosinolates, implying an additional C-S lyase; elevated auxin in sur1 depends on MYB34. supporting_text: we show that elevated auxin production in the sur1 plant depends on the MYB34 transcription factor reference_review: relevance: HIGH correctness: VERIFIED review_notes: Abstract-only cache; refines the earlier single-gene conclusion. - id: PMID:8589625 title: Superroot, a recessive mutation in Arabidopsis, confers auxin overproduction. findings: - statement: Original superroot mutant description; sur1 has excess adventitious and lateral roots and elevated free and conjugated IAA. reference_review: relevance: MEDIUM correctness: VERIFIED review_notes: Abstract-only; phenotype is indirect to SUR1 enzymology. - id: PMID:21712415 title: Cytosolic γ-glutamyl peptidases process glutathione conjugates in the biosynthesis of glucosinolates and camalexin in Arabidopsis. findings: [] reference_review: relevance: MEDIUM correctness: VERIFIED review_notes: Cached identifier/title and the relevant abstract or available full text checked during the module-member audit. The scope of target-specific evidence is qualified in annotation reasons and notes; a cached abstract is not treated as full text. suggested_questions: - question: Which enzyme provides the residual C-S lyase activity for indolic glucosinolates in sur1 mutants, and is it a paralog in the PTHR45744 family? - question: Is the physiological SUR1 substrate the Cys-Gly or the Cys conjugate produced after GGP1 action, and does SUR1 retain any aminotransferase side activity? - question: How much of the sur1 lethality is due to auxin excess versus accumulation of toxic glucosinolate intermediates? - question: Which paper was intended for the GO:0050832 defense response to fungus IDA keyed to PMID:32213638? That reference is a seed-dormancy study (ODR1/bHLH57) that does not mention SUR1 or any pathogen assay, so the annotation appears mis-keyed in the TAIR record. suggested_experiments: - description: Assay recombinant SUR1 kinetically with synthetic S-(alkylacetohydroximoyl)-L-cysteine and -cysteinylglycine conjugates of methionine-, phenylalanine- and tryptophan-derived precursors, and with tyrosine/2-oxoglutarate, to define its native substrate and exclude residual transaminase activity. - description: Profile glucosinolates and intermediates in sur1 myb34 and sur1 combined with candidate PTHR45744 paralog mutants to identify the additional indolic C-S lyase.