Virulence Groups and Molecular Diversity of Ralstonia solanacearum Strains Affecting Solanaceous Crops

Abstract

Ralstonia solanacearum is a highly destructive soil-borne bacterial pathogen responsible for bacterial wilt disease in a wide range of solanaceous crops, causing severe economic losses in tropical and subtropical agricultural regions. The present study investigated the virulence groups and molecular diversity of R. solanacearum strains collected from infected solanaceous crops to better understand pathogen variability and epidemiology. Diseased plant samples exhibiting characteristic wilt symptoms were collected from major crop-growing regions, and bacterial isolates were obtained using standard isolation and purification techniques. Pathogenicity assays were conducted on susceptible host plants to evaluate differences in virulence and disease severity among strains. Based on symptom development and aggressiveness, isolates were categorized into distinct virulence groups. Molecular characterization was performed using polymerase chain reaction (PCR)-based analyses and sequencing of conserved genomic regions to assess genetic diversity and phylogenetic relationships among the strains. The results revealed substantial variation in pathogenicity, with certain strains inducing rapid wilting and severe vascular browning in host plants. Molecular analysis demonstrated high genetic diversity within the pathogen population, indicating the presence of multiple genetically distinct lineages associated with different host crops and geographical regions. Phylogenetic clustering suggested possible adaptation of specific strains to particular environmental conditions and host species. The coexistence of diverse virulence groups and genetically variable populations highlights the complex epidemiology of bacterial wilt disease in solanaceous cropping systems. The findings provide valuable insights into pathogen evolution, host-pathogen interactions, and disease dissemination patterns. This study contributes to the development of effective resistance breeding programs and integrated disease management strategies aimed at minimizing bacterial wilt incidence and sustaining crop productivity.