A multimodal metabolomics approach using imaging mass spectrometry and liquid chromatography-tandem mass spectrometry for spatially characterizing monoterpene indole alkaloids secreted from roots

• Published in: Plant Biotechnology Vol. 38; no. 3; pp. 305 - 310
• Main Authors: Nakabayashi, Ryo, Takeda-Kamiya, Noriko, Yamada, Yutaka, Mori, Tetsuya, Uzaki, Mai, Nirasawa, Takashi, Toyooka, Kiminori, Saito, Kazuki
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese Society for Plant Biotechnology 25.09.2021; Japan Science and Technology Agency; Japanese Society for Plant Cell and Molecular Biology
• Subjects: Ajmalicine; Alkaloids; Chromatography; imaging mass spectrometry; Ions; Liquid chromatography; liquid chromatography-tandem mass spectrometry; Mass spectrometry; Mass spectroscopy; Metabolites; Metabolomics; Microorganisms; monoterpene indole alkaloid; Network analysis; Nitrogen isotopes; Original Paper; Roots; Scientific imaging; secretion; Serpentine; Soil microorganisms; Soils; Spectroscopy; Yohimbine
• ISSN: 1342-4580; 1347-6114
• DOI: 10.5511/plantbiotechnology.21.0504a

Plants release specialized (secondary) metabolites from their roots to communicate with other organisms, including soil microorganisms. The spatial behavior of such metabolites around these roots can help us understand roles for the communication; however, currently, they are unclear because soil-based studies are complex. Here, we established a multimodal metabolomics approach using imaging mass spectrometry (IMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to spatially assign metabolites under laboratory conditions using agar. In a case study using Catharanthus roseus, we showed that 58 nitrogen (N)-containing metabolites are released from the roots into the agar. For the metabolite assignment, we used 15N-labeled and non-labeled LC-MS/MS data, previously reported. Four metabolite ions were identified using authentic standard compounds as derived from monoterpene indole alkaloids (MIAs) such as ajmalicine, catharanthine, serpentine, and yohimbine. An alkaloid network analysis using dot products and spinglass methods characterized five clusters to which the 58 ions belong. The analysis clustered ions from the indolic skeleton-type MIAs to a cluster, suggesting that other communities may represent distinct metabolite groups. For future chemical assignments of the serpentine community, key fragmentation patterns were characterized using the 15N-labeled and non-labeled MS/MS spectra.