title: High resolution mass spectrometry imaging of plant tissues: towards a plant metabolite atlas.
abstract: Mass spectrometry (MS) imaging provides spatial and molecular information for a wide range of compounds. This tool can be used to investigate metabolic changes in plant physiology and environmental interactions. A major challenge in our study was to prepare tissue sections that were compatible with high spatial resolution analysis and therefore dedicated sample preparation protocols were established and optimized for the physicochemical properties of all major plant organs. We combined high spatial resolution (5 μm), in order to detect cellular features, and high mass accuracy (<2 ppm root mean square error), for molecular specificity. Mass spectrometry imaging experiments were performed in positive and negative ion mode. Changes in metabolite patterns during plant development were investigated for germination of oilseed rape. The detailed localization of more than 90 compounds allowed assignment to metabolic processes and indicated possible functions in plant tissues. The 'untargeted' nature of MS imaging allows the detection of marker compounds for the physiological status, as demonstrated for plant-pathogen interactions. Our images show excellent correlation with optical/histological examination. In contrast to previous MS imaging studies of plants, we present a complete workflow that covers multiple species, such as oilseed rape, wheat seed and rice. In addition, different major plant organs and a wide variety of compound classes were analyzed. Thus, our method could be used to develop a plant metabolite atlas as a reference to investigate systemic and local effects of pathogen infection or environmental stress.
authors.affiliation: Justus Liebig University Giessen, Institute of Inorganic and Analytical Chemistry, Schubertstrasse 60, Building 16, 35392 Giessen, Germany.
authors.forename: Dhaka Ram
authors.initials: DR
authors.lastname: Bhandari
authors.affiliation: Justus Liebig University Giessen, Department of Plant Breeding, IFZ, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany. Sven.Gottwald@agrar.uni-giessen.de.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Justus Liebig University Giessen, Department of Plant Breeding, IFZ, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany. Sven.Gottwald@agrar.uni-giessen.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Friedt
authors.affiliation: Justus Liebig University Giessen, Institute of Inorganic and Analytical Chemistry, Schubertstrasse 60, Building 16, 35392 Giessen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Spengler
authors.affiliation: Justus Liebig University Giessen, Department of Plant Breeding, IFZ, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany. Sven.Gottwald@agrar.uni-giessen.de.
authors.forename: Sven
authors.initials: S
authors.lastname: Gottwald
authors.affiliation: Justus Liebig University Giessen, Institute of Inorganic and Analytical Chemistry, Schubertstrasse 60, Building 16, 35392 Giessen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Römpp
mesh_terms: D005670:Fusarium / Q000302:isolation & purification; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D012275:Oryza / Q000378:metabolism* / Q000648:ultrastructure; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism / Q000648:ultrastructure; D018547:Plant Stems / Q000378:metabolism* / Q000648:ultrastructure; D012639:Seeds / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014908:Triticum / Q000378:metabolism* / Q000382:microbiology / Q000648:ultrastructure