Localization of small molecules in plant tissues visualized by an imaging mass spectrometer

Abstract

Imaging mass spectrometry (IMS) is a new tool to map the spatial distribution of molecules on the biological materials. Recently, we applied IMS to intact plant tissues or thin slices by using a combination of manufactured apparatus and commercial mass spectrometers. The present work is concerned with the refinement of MALDI/laser desorption/ionization (LDI)-Fourier transform ion cyclotron resonance (FTICR)-MS incorporating certain specific features namely, ultra-high mass resolution (>100,000), ultra-high molecular mass accuracy (<1 ppm) and high spatial resolution (<10 μm) for imaging MS of plant tissues. The IMS analysis succeeded in visualizing of cellular localization of small molecules of intact Arabidopsis thaliana roots and Catharanthus roseus stem tissues glued to a small conductive glass with and without a matrix substance. The images of various small metabolites representing their two-dimensional distribution on the dried intact tissues were obtained.