MALDI‐imaging mass spectrometry – An emerging technique in plant biology

Abstract

Recent advances in instrumentation and sample preparation have facilitated the mass spectrometric (MS) imaging of a large variety of biological molecules from small metabolites to large proteins. The technique can be applied at both the tissue and the single-cell level, and provides information regarding the spatial distribution of specific molecules. Nevertheless, the use of MS imaging in plant science remains far from routine, and there is still a need to adapt protocols to suit specific tissues. We present an overview of MALDI-imaging MS (MSI) technology and its use for the analysis of plant tissue. Recent methodological developments have been summarized, and the major challenges involved in using MALDI-MSI, including sample preparation, the analysis of metabolites and peptides, and strategies for data evaluation are all discussed. Some attention is given to the identification of differentially distributed compounds. To date, the use of MALDI-MSI in plant research has been limited. Examples include leaf surface metabolite maps, the characterization of soluble metabolite translocation in planta, and the profiling of protein/metabolite patterns in cereal grain cross-sections. Improvements to both sample preparation strategies and analytical platforms (aimed at both spectrum acquisition and post-acquisition analysis) will enhance the relevance of MALDI-MSI technology in plant research.

MALDI Mass Spectrometry Imaging for the Simultaneous Location of Resveratrol, Pterostilbene and Viniferins on Grapevine Leaves

“…For mass spectrometry imaging purpose, MALDI has already been used to map different metabolites on plant organs [28] such as lipids on leaf surface [29], flavonoids or glycoalkaloid in roots and root nodules [30,31], sugars within seed or stem sections [32,33]. Different matrices are described in the literature for MALDI MS analysis of vegetable material such as 1,5 diamino naphthalene (DAN) or 9-amino acridine (9-AA) in negative ion mode, and tri-hydroxy acetophenone (THAP), α-cyano-4-hydroxy cinamic acid (CHCA) or 2,5 dihydroxy-benzoic acid (DHB) in positive ion mode.…”

Spatio-Temporal Dynamics of Fructan Metabolism in Developing Barley Grains

“…The visualization of metabolites has been facilitated by MSI (Kaspar et al, 2011;Matros and Mock, 2013), while MALDI MSI has allowed for the analysis of certain key molecules with a high level of spatial resolution (Caprioli et al, 1997) and has been proven to be applicable to plant material (Matros and Mock, 2013, and references therein). The MS instrument creates an array of mass spectra, where each spot represents its own m/z profile.…”

The Use of Auxin Quantification for Understanding Clonal Tree Propagation

“…These techniques provide simultaneous high-resolution identification and imaging of compounds to visualize their distribution in plant tissue [144][145][146][147]. They have been applied extensively to study the distribution of drugs and their metabolites in human and animal tissues [145,148].…”