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Sample Set Information

ID TSE1326
Title Omics-based approaches to methionine side chain elongation in Arabidopsis: characterization of the genes encoding methylthioalkylmalate isomerase and methylthioalkylmalate dehydrogenase.
Description Glucosinolates (GSLs) are secondary metabolites in Brassicaceae plants synthesized from amino acids. Methionine-derived GSLs (Met-GSLs) with diverse side chains of various lengths are the major GSLs in Arabidopsis. Methionine chain elongation enzymes are responsible for variations in chain length in Met-GSL biosynthesis. The genes encoding methionine chain elongation enzymes are considered to have been recruited from the leucine biosynthetic pathway in the course of evolution. Among them, the genes encoding methylthioalkylmalate synthases and aminotransferases have been identified; however, the remaining genes that encode methylthioalkylmalate isomerase (MAM-I) and methylthioalkylmalate dehydro-genase (MAM-D) remain to be identified. In a previous study based on transcriptome co-expression analysis, we identified candidate genes for the large subunit of MAM-I and MAM-D. In this study, we confirmed their predicted functions by targeted GSL analysis of the knockout mutants, and named the respective genes MAM-IL1/AtleuC1 and MAM-D1/AtIMD1. Metabolic profiling of the knockout mutants of methionine chain elongation enzymes, conducted by means of widely targeted metabolomics, implied that these enzymes have roles in controlling metabolism from methionine to primary and methionine-related secondary metabolites. As shown here, an omics-based approach is an efficient strategy for the functional elucidation of genes involved in metabolism.
Authors Sawada Y, Kuwahara A, Nagano M, Narisawa T, Sakata A, Saito K, Hirai MY.
Reference Plant Cell Physiol. 2009 Jul;50(7):1181-90. doi: 10.1093/pcp/pcp079. Epub 2009 Jun 3.

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Sample Information

Title Arabidopsis thaliana
Organism - Scientific Name Arabidopsis thaliana
Organism - ID NCBI taxonomy:3702
Compound - ID
Compound - Source
Preparation As knockout mutants of AtLeuC1 and AtIMD1, two allelic lines of the respective genes [SALK_029510 (atleuc1-1) and SALK_065789 (atleuc1-2) for AtLeuC1, and SALK_063423 (atimd1-1) and SALK_ 069991 (atimd1-2) for AtIMD1] were used. In atleuc1-1, atimd1-1 and atimd1-2, expression of the corresponding gene was almost completely repressed. In atleuc1-2, transcript levels for AtLeuC1 were reduced but not completely repressed (Supplementary Fig. S1B). Knockout lines of AtBCAT4 (SALK_013627, bcat4-1) have already been reported (Schuster et al. 2006). As MAM1, MAM3 and AtLeuD1 knockout lines, SALK_012677 (mam1), SALK_004536 (mam3) and SALK_048320 (atleud1-1) were used. Homozygous lines of the T-DNA insertion mutants were selected by genomic PCR according to the T-DNA Express: Arabidopsis iSect Tool manual ( Wild-type Arabidopsis thaliana (accession Colombia) and mutants (T-DNA insertion lines) were grown in a pre-fabricated room-type chamber at 22°C and a 16 h photoperiod in soil (PRO-MIX BX, Premier Horticulture, Rivière-du-Loup, QC, Canada) for seed collection, or on agar-solidified 1/2 Murashige–Skoog medium containing 1% sucrose for GSL analysis and widely targeted metabolomics.
Sample Preparation Details ID

Analytical Method Information

Method Details ID MS2
Sample Amount

Analytical Method Details Information

Title UPLC-TQD (Widely targeted metabolomics)
Instrument UPLC-TQD system (Waters)
Instrument Type UPLC-QTOF-MS
Ionization ESI
Ion Mode Positive and Negative
Description Approximately 50–100 mg of leaves (3 weeks after germination for mam1 and mam3, and 4 weeks after germination for atleuc1 and atimd1) of wild-type and mutant Arabidopsis lines were used for widely targeted metabolomics using UPLC-TQD (Waters) as previously described (Sawada et al. 2009). Analytical conditions for UPLC-TQD are released in our data repository and distribution site DROP Met at our website PRIMe (

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Data Analysis Information

Title Data processing (UPLC-TQD)
Data Analysis Details ID DS1
Recommended decimal places of m/z

Data Analysis Details Information

Title Data processing (Widely targeted metabolomics)
Description Metabolites were annotated based on the retention time and multiple reaction monitoring conditions of authentic compounds. The metabolites whose accumulation levels significantly changed were identified by Welch’s t-test using the Microsoft Excel (Microsoft, Redmond, WA, USA) function (TTEST, Tails = 2, Type = 3).
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