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タイトル A novel method for single-grain-based metabolic profiling of Arabidopsis seed
ジャーナル Metabolomics  02 May 2017  13()  75 
著者 Yuji Sawada, Hirokazu Tsukaya, Yimeng Li, Muneo Sato, Kensuke Kawade, Masami Yokota Hirai
抄録 Introduction In plant metabolomics, metabolite contents are often normalized by sample weight. However, accurate weighing of very small samples, such as individual Arabidopsis thaliana seeds (approximately 20 µg), is difficult, which may lead to irreproducible results. Objectives We aimed to establish alternative normalization methods for seed-grain-based comparative metabolomics of A. thaliana. Methods Arabidopsis thaliana seeds were assumed to have a prolate spheroid shape. Using a microscope image of each seed, the lengths of major and minor axes were measured by fitting a projected 2-dimensional shape of each seed as an ellipse. Metabolic profiles of individual diploid or tetraploid A. thaliana seeds were measured by our highly sensitive protocol (“widely targeted metabolomics”) that uses liquid chromatography coupled with tandem quadrupole mass spectrometry. Mass spectrometric analysis of 1 µL of solution extract identified more than 100 metabolites. The data were normalized by various seed-size measures, including seed volume (single-grain-based analysis). For comparison, metabolites were extracted from 4 mg of diploid and tetraploid A. thaliana seeds and their metabolic profiles were analyzed by normalization of weight (weight-based analysis). Results A small number of metabolites showed statistically significant differences in the single-grain-based analysis compared to weight-based analysis. A total of 17 metabolites showed statistically different accumulation between ploidy types with similar fold changes in both analyses. Conclusion Seed-size measures obtained by microscopic imaging were useful for data normalization. Single-grain-based analysis enables evaluation of metabolism of each seed and elucidates the metabolic profiles of precious bioresources by using small amounts of samples.

 シロイヌナズナ種子1粒のメタボローム分析

理研環境資源科学研究センター 代謝システム研究チーム 平井優美  投稿日時[2017-06-27 12:35:57]

メタボローム解析では多くの場合、試料の重さでデータをノーマライズするが、シロイヌナズナ種子1粒の分析にこの方法を適用するのは現実的ではない。本論文では、種子の顕微鏡画像を利用して計算した体積でノーマライズすることで、シロイヌナズナ種子1粒の代謝プロファイルを評価する方法を確立した。