MALDI-MSI method for the detection of large biomolecules in plant leaf tissue

In this study we describe a method for the detection of biomolecules (in the polypeptide m/z range) directly from the surface of plant leaves by using Mass Spectrometry Imaging. The plant-pathogen interaction between Arabidopsis thaliana and the bacterium Xanthomonas campestris pv. campestris was analyzed by comparing infected and non-infected leaf discs submitted to mass spectrometry. The total surface area of ion distribution was calculated for both samples, revealing 23 ions, out of which 3 showed statistical significance. Although these ions were not identified, the results showed that this approach can be successfully applied for the detection of potential polypeptide biomarkers directly on leaf tissue, which is a major challenge in MALDI-Imaging studies.