Host-Specific Adaptations and Global Transmission Potential of a Mexican ToBRFV Isolate: Insights from Genomic Analysis

The tomato brown rugose fruit virus (ToBRFV) poses a severe global threat to tomato and pepper production due to its high transmissibility and genetic adaptability. This study provides an in-depth characterization of a Mexican ToBRFV isolate, integrating genomic variability analysis, host-specific investigations, and seed transmission studies to better understand the viruss adaptability and dissemination pathways. Phylogenetic analysis places this Mexican isolate in close genetic proximity to strains from Israel and China, suggesting cross-regional transmission potentially facilitated by agricultural trade. Genomic comparison with 100 ToBRFV isolates revealed a notable balance between genomic stability and host-specific adaptations, particularly within the 126-kDa replicase domain proteins critical for viral replication. Specific single nucleotide variants (SNVs) were identified in these regions, exhibiting host-dependent patterns; Solanum lycopersicum (tomato) isolates maintained consistent profiles, whereas isolates from Capsicum annuum (pepper) and Citrullus lanatus (watermelon) displayed unique substitutions. These variations suggest distinct selection pressures across hosts, potentially optimizing viral replication and survival in specific plant environments. Experimental bioassays confirmed that the Mexican isolate could infect additional species, including Physalis ixocarpa, and Solanum melongena, thereby expanding the known host range of ToBRFV. Seed transmission studies conducted on N. rustica revealed a 30% reduction in germination rates for infected seeds compared to healthy controls, highlighting the viruss impact on seed viability and underscoring the necessity of stringent biosecurity protocols. This comprehensive analysis enhances our understanding of the Mexican ToBRFV isolate genetic diversity, host specificity, and transmission dynamics.