Taxonomic group: plant / Streptophyta
(Phylum: Streptophyta)
Organ / tissue: flower
Publication DOI: 10.1105/tpc.108.058040Journal NLM ID: 9208688Publisher: Rockville, MD: American Society of Plant Physiologists
Correspondence: ksaito
faculty.chiba-u.jp
Institutions: RIKEN Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan, Graduate School of Pharmaceutical Sciences, Chiba University, Inage-ku, Chiba 263-8522, Japan
To complete the metabolic map for an entire class of compounds, it is essential to identify gene-metabolite correlations of a metabolic pathway. We used liquid chromatography-mass spectrometry (LC-MS) to identify the flavonoids produced by Arabidopsis thaliana wild-type and flavonoid biosynthetic mutant lines. The structures of 15 newly identified and eight known flavonols were deduced by LC-MS profiling of these mutants. Candidate genes presumably involved in the flavonoid pathway were delimited by transcriptome coexpression network analysis using public databases, leading to the detailed analysis of two flavonoid pathway genes, UGT78D3 (At5g17030) and RHM1 (At1g78570). The levels of flavonol 3-O-arabinosides were reduced in ugt78d3 knockdown mutants, suggesting that UGT78D3 is a flavonol arabinosyltransferase. Recombinant UGT78D3 protein could convert quercetin to quercetin 3-O-arabinoside. The strict substrate specificity of UGT78D3 for flavonol aglycones and UDP-arabinose indicate that UGT78D3 is a flavonol arabinosyltransferase. A comparison of flavonol profile in RHM knockout mutants indicated that RHM1 plays a major role in supplying UDP-rhamnose for flavonol modification. The rate of flavonol 3-O-glycosylation is more affected than those of 7-O-glycosylation by the supply of UDP-rhamnose. The precise identification of flavonoids in conjunction with transcriptomics thus led to the identification of a gene function and a more complete understanding of a plant metabolic network.
Structure type: monomer ; 465
Location inside paper: Figure 3
Trivial name: f16
Contained glycoepitopes: IEDB_142488,IEDB_146664,IEDB_983931,SB_192
Methods: 1H NMR, ESI-TOF-MS, enzymatic assay, ESI-TOF-MS/MS, genetic manipulations, UPLC-PDA-ESI/Q-TOF/MS
Enzymes that release or process the structure: UGT78D2
Related record ID(s): 60898, 60899, 60900, 60901, 60902, 60903, 60904, 60905, 60906, 60907, 60909, 60910, 60911, 60912, 60913, 60914, 60915, 60916, 60917, 60918, 60919, 60920, 62231
NCBI Taxonomy refs (TaxIDs): 3702
Show glycosyltransferases
There is only one chemically distinct structure:
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