Identification of Begomovirus Genomic Components and Stress-specific Metabolic Markers in Mungbean Leaf Apoplast

Plant viruses exert control over the host metabolism to enhance their survival, but the specific sites where altered metabolites take effect remain enigmatic. This study focuses on the apoplastic region of symptomatic mungbean leaves infected with mungbean yellow mosaic India virus (MYMIV) to gain new insights into metabolite changes during infection. Leveraging NMR-based metabolome fingerprinting, we identified several stress-associated metabolites. Notably, proline and 2-Hydroxybutyrate were found to be up-regulated in the apoplast region, while down-regulated in the cytosol. Additionally, aspartate was found to be upregulated in the cytosolic region but absent in the apoplast. Importantly, our molecular analysis of the apoplast suggests the presence of MYMIV genomic components. Moreover, we characterized two distinct populations of extracellular vesicles (EVs) using ultracentrifugation, transmission electron microscopy, dynamic light scattering, and fluorometric assays. The data revealed alterations in the size and count of EVs, suggesting their potential role in facilitating the transport of viral components for long-distance cell-to-cell movement during infection. These findings provide valuable insights into the apoplasts role and the significance of EVs in MYMIV infection, contributing to a better understanding of virus-host interactions and potentially informing new virus defense strategies.