Nanoscale carbon quantum dots activate antiviral immune responses and modulate the heterogeneous nuclear...

Plant viruses threaten global food security by subverting host defenses, necessitating sustainable solutions. Carbon quantum dots (CQDs)-nanoscale materials with tunable optoelectronic properties and biocompatibility, offer promise in antiviral therapy, but their mechanisms in plant immunity remain unclear. This study comprehensively mapped CQDs-modulated transcriptional reprogramming of antiviral responses in association with the diversity and patterns of alternative splicing (AS) events in cotton leaf curl Multan virus CLCuMuV (DNA-A + β)-infected Nicotiana benthamiana. Transcriptomic analysis revealed that at 5 days post-inoculation (dpi) with CLCuMuV (DNA-A + β), the CQDs upregulated antiviral immunity-related genes (Ca⁺²/calmodulin-dependent protein kinase (CaMK), WRKY transcription factors, mitogen-activated protein kinase (MAPK), and serine/threonine protein kinases (STPKs) and stress-responsive immunity pathways. At 20 dpi, the transcriptional response shifted to reflect reduced virus-induced stress. Moreover, the CQDs differentially impacted AS patterns by increasing exon skipping and modulating intron retention, mainly at later stages of viral infection. Structural modeling revealed that the CQDs induced conformational changes in the RRM domain-containing heterogeneous nuclear ribonucleoprotein (hnRNP), enhancing protein druggability and binding capacity. These findings indicate the dynamic role of CQDs in the modulation of antiviral immune responses and the transcriptomic plasticity of plants during viral infection which is reflected by regulation of gene expression and alternative splicing. CQDs showed strong antiviral potential in alleviating symptoms of CLCuMuV via reprogramming transcriptional responses and differential AS events in N. benthamiana. These findings underscore CQDs as effective tools for enhancing plant resilience against viral pathogens. Future research should explore field efficacy of CQDs and their nanoscale interactions with viral proteins and their broader applications in sustainable crop protection.