title: Unbiased profiling of volatile organic compounds in the headspace of Allium plants using an in-tube extraction device.
abstract: BACKGROUND
  Plants produce and emit important volatile organic compounds (VOCs), which have an essential role in biotic and abiotic stress responses and in plant-plant and plant-insect interactions. In order to study the bouquets from plants qualitatively and quantitatively, a comprehensive, analytical method yielding reproducible results is required.
  
  
  RESULTS
  We applied in-tube extraction (ITEX) and solid-phase microextraction (SPME) for studying the emissions of Allium plants. The collected HS samples were analyzed by gas chromatography-time-of-flight-mass spectrometry (GC-TOF-MS), and the results were subjected to multivariate analysis. In case of ITEX-method Allium cultivars released more than 300 VOCs, out of which we provisionally identified 50 volatiles. We also used the VOC profiles of Allium samples to discriminate among groups of A. fistulosum, A. chinense (rakkyo), and A. tuberosum (Oriental garlic). As we found 12 metabolite peaks including dipropyl disulphide with significant changes in A. chinense and A. tuberosum when compared to the control cultivar, these metabolite peaks can be used for chemotaxonomic classification of A. chinense, tuberosum, and A. fistulosum.
  
  
  CONCLUSIONS
  Compared to SPME-method our ITEX-based VOC profiling technique contributes to automatic and reproducible analyses. Hence, it can be applied to high-throughput analyses such as metabolite profiling.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan. kusano.miyako.fp@u.tsukuba.ac.jp.|RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan. kusano.miyako.fp@u.tsukuba.ac.jp.
authors.forename: Miyako
authors.initials: M
authors.lastname: Kusano
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan. kobamako@riken.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan. yiizuka5@gmail.com.|Department of Genome System Science, Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa, Japan. yiizuka5@gmail.com.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Iizuka
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan. atsushi.fukushima@riken.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukushima
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan. kazuki.saito@riken.jp.|Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Chiba, Japan. kazuki.saito@riken.jp.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
mesh_terms: D000490:Allium / Q000737:chemistry / Q000145:classification* / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D055442:Metabolome / Q000502:physiology*; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000295:instrumentation* / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D055549:Volatile Organic Compounds / Q000145:classification / Q000302:isolation & purification*
chemical_list: D010936:Plant Extracts; D055549:Volatile Organic Compounds