Vol. 11, Issue 12 (2022)

Author(s):
Pruthviraj, MK Naik, MY Sreenivasa, R Ganesha Naik, MS Nandish and B Gangadhara Naik

Abstract:
Bacterial wilt of tomato caused by Ralstonia solanacearum is one of the most destructive diseases of tomato in major tomato growing regions of our country. A research work was undertaken characterize the causal agent of bacterial wilt of tomato by bio-chemical and molecular characterization. R. solanacearum colonies on Nutrient Agar (NA) medium were dirty white, smooth, round and elevated. R. solanacearum colonies grown on TZC media were white with pink centers, while colonies grown on Casamino Peptone Glucose (CPG) medium were white or cream-colored, irregularly shaped, fluidal, and opaque. R. solanacearum was Gram negative, catalase positive, KOH positive and also gave positive reaction for starch hydrolysis, methyl red test and H2S production but gave negative reaction for gelation liquification. Molecular characterization of pathogen was carried out by using bacterial universal primers and showed amplification at 1500-bp. Sequence analysis reveled that that pathogen was R. solanacearum. Under glasshouse conditions, Koch's postulate was used to determine the test bacterium's pathogenicity, and it was shown to be pathogenic.