P-437 - Identification of the transcriptional landscape of the geminiviral infection in tomato using single-cell RNA sequencing

Geminiviruses are insect-transmitted plant viruses with circular single-stranded DNA genomes that cause severe crop diseases worldwide. Viral infection reshapes the plant transcriptome; however, previous analyses, primarily using whole organs, may not reflect the specific changes happening in infected cells. This inaccuracy is due to the low representation of infected cells in the total population and the frequent phloem-restricted nature of geminiviruses. In this work, we used high-throughput single-cell RNA sequencing (scRNA-seq) to profile over 30,000 cells from tomato leaves infected with tomato yellow leaf curl virus (TYLCV) or mock-inoculated controls. By examining global gene expression and cell-type-specific markers, we identified seven major cell types: mesophyll, epidermis, guard cells, bundle sheath, vasculature, proliferating cells, and distinct virus-responsive cells. Gene-signature scoring and differentially expressed gene (DEG) analysis revealed cell-type-specific responses to viral infection, particularly in the vasculature and virus-responsive cells. Additionally, pseudotime trajectory analysis of the vasculature uncovered TYLCV-induced alterations in the vascular cambium. Taken together, these findings unveil cell-autonomous and systemic transcriptional responses to the viral infection at a single-cell level, and offer a valuable resource for investigating plant-geminivirus interactions, potentially guiding the design of effective anti-viral strategies.