First Report of Soft Rot Disease of Papaya Caused by Klebsiella variicola in Bangladesh

Twelve bacteria were isolated from soft rotten papaya collected from markets of different locations of Gazipur district, Bangladesh. Among these, five isolates (CP01-CP05) cased soft rot symptoms on potato slices. The isolates also produced dark brown to blackish characteristics soft rot symptoms on papaya fruit by artificial inoculation. The isolates were Gram-negative and also negative in oxidase, methyl red, arginine dihydrolase, gelatin liquefaction and indole tests. All of the isolates were positive in catalase, oxidative fermentative, nitrate reduction, acetoin and urease production tests. The isolates grew well at 41°C and 5% of salt concentration. They utilized lactose, glucose, rhamnose, sucrose, melibiose, arabinose, mannitol, inositol, sorbitol and citrate but not adonitol as sole sources of carbon. Phylogenetic analysis based on 16 S rRNA gene sequence indicated that an isolate CP03 was closely related with K. variicola. These results suggested that the isolates from the diseased papaya were K. variicola. This study reports for the first time K. variicola causing soft rot of papaya in Bangladesh.