SE159:/DS1

Sample Set Information

ID	TSE1316
Title	Comprehensive flavonol profiling and transcriptome coexpression analysis leading to decoding gene-metabolite correlations in Arabidopsis.
Description	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.
Authors	Yonekura-Sakakibara K, Tohge T, Matsuda F, Nakabayashi R, Takayama H, Niida R, Watanabe-Takahashi A, Inoue E, Saito K.
Reference	Plant Cell. 2008 Aug;20(8):2160-76. doi: 10.1105/tpc.108.058040. Epub 2008 Aug 29.
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PubMed

Data Analysis Details Information

ID	DS1
Title	Data processing and analisys
Description	For comprehensive flavonol profiling, nonprocessed MS data were converted to NetCDF format by MassLynx software (Micromass MS Technologies). Data analyses including principal component analysis were performed by the Phenomenome Profiler (Phenomenome Discoveries). Flavonol glycoside standards were used for the identification of the peaks in the plant extracts based on retention times, UV-visible absorption spectra, and mass fragmentation by tandem MS analysis. Other flavonol peaks were annotated by comparing their UV-visible absorption spectra, elution times, m/z values, and MS2 fragmentation patterns with 85 reference flavonoid compounds and the reported data (Tohge et al., 2005, 2007; Routaboul et al., 2006; Yonekura-Sakakibara et al., 2007). The mass spectrum data of standard compounds (see Supplemental Data Set 2 online) were recorded in the MASSBANK Database (http://www.massbank.jp/index-e.html).
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