Isolation, identification and molecular characterization of Ralstonia solanacerum isolates collected from Southern Karnataka

Abstract

Bacterial wilt caused by Ralstonia solanacearum, is the major threat to tomato cultivation in all tomato growing areas of Karnataka. R. solanacearum was isolated from the infected host plants collected from different locations of southern Karnataka. The identity of the isolates was established using morphological, biochemical, and molecular analysis using species specific PCR primers. The race and biovar specificity of pathogen was determined through pathogenicity test on different host plants and the ability of isolates to use carbohydrates, respectively. Phylotype classification was done by phylotype specific multiplex PCR using phylotype specific primers. All the bacterial isolates showed the characteristic creamy white fluidal growth with pink centre on the Tetrazolium chloride medium. Further, the isolates amplified at 280 bp, which confirmed the identity of pathogen as Ralstonia solanacearum. Our results showed that all isolates belonged to Race 1 of the pathogen. Among different isolates obtained, four isolates each were identified to be Biovar III and Biovar IIIA, repectively, while two isolates were identified as Biovar IIIB. All the ten isolates were affiliated to Phylotype I of Ralstonia solanaceraum species complex. These findings may help in devising the management practices for bacterial wilt of tomato in southern Karnataka.

Managingtomato bacterial wilt by suppressing Ralstonia solanacearum population in soil and enhancing host resistance through fungus-derived furoic acid compound

“…Several studies have reported the difficulties of managing R. solanacearum because of its endogenous growth in plants, soil persistency in deeper layers, and water dispersal and its link with weeds ( Nion and Toyota, 2015 ). Teli et al. (2018) also reported that management strategies such as crop rotation, field sanitation, and the use of disease-resistant cultivars have mostly failed to control R. solanacearum .…”

“…Several studies have reported the difficulties of managing R. solanacearum because of its endogenous growth in plants, soil persistency in deeper layers, and water dispersal and its link with weeds (Nion and Toyota, 2015). Teli et al (2018) also reported that management strategies such as crop rotation, field sanitation, and the use of disease-resistant cultivars have mostly failed to control R. solanacearum. Although synthetic chemicals have shown some effective results, they are linked with soil, underground water and air pollution, biodiversity loss, and residual toxicity impacts (Hassan and Chang, 2017;Fan et al, 2019;Malerba and Cerana, 2019).…”