Spatially resolved analysis of small molecules by matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI)

• Published in: The New phytologist Vol. 193; no. 3; pp. 806 - 815
• Main Authors: Peukert, Manuela, Matros, Andrea, Lattanzio, Giuseppe, Kaspar, Stephanie, Abadía, Javier, Mock, Hans‐Peter
• Format: Journal Article
• Language: English
• Published: Oxford, UK New Phytologist Trust 01.02.2012; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: Adaptation; Barley; barley grains; Cryoultramicrotomy; Desorption; Distribution patterns; Grains; Hordeum; Hordeum - metabolism; Hordeum vulgare; image analysis; Imaging; Imaging spectrometers; Imaging techniques; Imaging, Three-Dimensional; Imaging, Three-Dimensional - methods; Ionization; Ions; Lasers; MALDI‐MSI; Mass spectrometers; mass spectrometry; Mass spectroscopy; Medicinal plants; metabolism; Methods; Nicotiana - metabolism; Nicotiana tabacum; Optimization; Plant tissues; Plants; proteins; Reproducibility of Results; roots; Sample preparation; Sectioning; small molecules; Spatial analysis; Spatial discrimination; Spatial distribution; Spatial resolution; Spectrometry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Statistics as Topic; Tissue; Tobacco; tobacco roots
• ISSN: 0028-646X; 1469-8137; 1469-8137
• DOI: 10.1111/j.1469-8137.2011.03970.x

Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) of tissues provides the means to analyse the spatial distributions of small molecules and proteins within tissues. This imaging technique is commonplace in medicinal and pharmaceutical research, but its application in plant science is very recent. Broader introduction requires specific adaptations for plant tissues. Sample preparation is of paramount importance in order to obtain high-quality spectra providing sufficient spatial resolution for compounds. Optimization is required for sectioning, choice of matrix and means of matrix deposition. Here, we present our current protocols for the detection of small molecules in cryodissected immature barley (Hordeum vulgare) grains and tobacco (Nicotiana tabacum) roots. Examples of MALDI-MSI measurements are provided, and the level of reproducibility across biological replicates is addressed. Furthermore, our approaches for the validation of distribution patterns and for the identification of molecules are described. Finally, we discuss how MALDI-MSI can contribute to applied plant research.