Characterization and diversity of Indian isolates of Ralstonia solanacearum inciting bacterial wilt of tomato

Tomato (Solanum lycopersicum L.) a native of South America is a source of vitamins, minerals and antioxidant lycopene, and considered as protective food. In India, the crop is grown under the area of about 0.458 M ha with production of 7.277 M mt and productivity of 15.9 mt/ha. Biotic factors play a role in low productivity of the crops in India. Among various diseases, bacterial wilt disease incited by Ralstonia solanacearum (Smith) Yabuuchi et al. (1996) is a devastating bacterium causing damage to the crop ranging from 2 to 95% depending on the seasons and cultivars. In India, majority of the isolates of R. solanacearum infecting tomato crop belonged to biovar 3, race 1 and phylotype I. However, less than 10% isolates of the bacteria belonged to biovar 4 particularly in the states of Jharkhand and Himachal Pradesh. The genetic diversity of R. solanacearum has been studied by using methods such as random amplified polymorphic DNA (RAPD), PCR—RFLP (PCR—Restriction Length Fragment Polymorphism) of hrp gene, Repetitive element palindromic-polymerase chain reaction (Rep-PCR) and multilocus sequence typing (MLST). The genetic diversity was recorded in Indian R. solanacearum isolates irrespective of their occurrence in different agro-climatic conditions. © 2021, Indian Phytopathological Society.