Mass spectrometry imaging: principles and applications in plant research

Mass spectrometry imaging (MSI) is an advanced analytical technique that combines mass spectrometry with spatial mapping, enabling the direct, label-free detection and visualization of molecular distributions within biological tissues. This review comprehensively outlines the fundamental principles, major technological platforms, and recent applications of MSI in plant science. We detail key ionization techniques - matrix-assisted laser desorption/ionization (MALDI), desorption electrospray ionization (DESI), and secondary ion mass spectrometry (SIMS) - focusing on their ionization mechanisms and instrumental characteristics. We then highlight the transformative impact of MSI in plant research, specifically covering: plant metabolomics, localization of bioactive compounds in medicinal plants, elucidation of plant-microbe interaction mechanisms, and studies of plant responses to environmental stresses. Finally, we discuss current challenges and future directions for the technology. Due to its high sensitivity, spatial resolution, and label-free capability, MSI has become a pivotal tool for uncovering plant physiological processes and metabolic regulatory networks, demonstrating significant potential for broad application in plant science.