3D Mass Spectrometry Imaging as a Novel Screening Method for Evaluating Biocontrol Agents

The aim of this study was to evaluate innovative mass spectrometry imaging (MSI) for determining the metabolic potential of selected soil bacteria from the genera <i>Bacillus</i> and <i>Priestia</i> in the presence of the phytopathogen <i>Fusarium</i>. This research marks the first application of direct 3D MSI that to visualize interactions between potential biocontrol agents and plant pathogens on agar medium. The LARAPPI/CI-3D-MSI (Laser-Assisted Remote Atmospheric Pressure Imaging/Chemical Ionization-3D Mass Spectrometry Imaging) setup provided valuable insights into the compounds produced by the tested microorganisms, revealing their spatial distributions and their ability to diffuse into the agar medium. Subsequently, a Pathway Impact Analysis of Metabolites was conducted. Ion images based on ultrahigh resolution mass spectrometry data were obtained, including for potentially bioactive compounds. Statistical analysis of the entire MS data set showed that the metabolites identified for <i>Bacillus licheniformis</i> samples were distinctly separated from the <i>Priestia megaterium</i> samples and could be helpful tools for screening biocontrol strains. The LARAPPI/CI MSI technique offers significant advantages over existing MSI methods. Further research using this technology could help validate the effectiveness of various biopreparations and contribute to enhancing the quality of biological plant protection products available on the market.