In Vivo Identification and Spatial Distribution of Crown Gall Disease Biomarkers in Grapevine.

Grapevine crown gall is caused by the tumorigenic bacterium Allorhizobium vitis. The fight against this disease is a major challenge in viticulture since this pathogen can systemically colonize the plant host, persisting in vineyards once infected. Understanding the dynamics of the plant-pathogen relationship not only improves our knowledge of plant biology but also could lead to innovative strategies for sustainable agricultural practices. In this way, this study aimed to gain insights into metabolic changes occurring in the tumor induced by A. vitis, using two techniques, Water-Assisted Laser Desorption/Ionization Mass Spectrometry (WALDI) and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI MSI). We highlighted compounds such as phenolics alongside specific lipids acting as stress signaling regulators. Moreover, vitopine, produced after plant cell transformation by A. vitis and exclusively found in infected plants, was successfully identified by real time detection by SpiderMass and localized for the first time through MSI. We illustrate here the effectiveness of SpiderMass and MSI in identifying biomarkers of grapevine crown gall, enhancing our understanding of plant responses to bacterial infection. These techniques allow for real-time analysis and spatial distribution mapping of metabolites, paving the way for future research and potential applications in diagnostics.