Comparative genomic analysis of Agrobacterium salinitolerans provides insights into genetic diversity and pathogenic potential.

Agrobacterium spp. are widespread plant pathogens, particularly associated with crown gall disease, and their genomic features and ecological adaptations underlie complex plant-microbe interactions. Agrobacterium salinitolerans, a relatively understudied member of this genus, exhibits distinct genomic traits that may contribute to its pathogenicity and environmental persistence, yet its genetic architecture and adaptive mechanisms remain poorly characterized. In this study, we conducted a comparative genomic analysis of A. salinitolerans strain YN6, isolated from crown gall tissue of Rosa spp., alongside 14 publicly available A. salinitolerans genomes. Pan-genome analysis, supported by average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), revealed an open pan-genome structure indicative of high genetic diversity. This diversity is primarily driven by mobile genetic elements (MGEs) and horizontal gene transfer (HGT), while most core and accessory genes are maintained under purifying selection. We identified numerous virulence factors and antibiotic resistance genes linked to macromolecular secretion systems, underscoring the strain's genomic features associated with plant-pathogenic interactions. Additionally, a rich repertoire of carbohydrate-active enzyme (CAZyme) genes was detected, suggesting broad metabolic versatility and enhanced survival across diverse ecological niches. This study provides a comprehensive genomic characterization of A. salinitolerans, revealing its high genetic plasticity, evolutionary dynamics, and multifaceted ecological adaptations. The findings highlight the species genetic repertoire linked to host colonization and environmental survival strategies, laying a critical foundation for future functional genomic investigations.