Isolation and Characterization of Phylloplane Bacteria from Papaya Plant for the Biocontrol of post-harvest Diseases in Papaya

Abstract

Papaya is one of the most significant crops cultivated in tropical and subtropical countries all over the world. Post-harvest diseases are the major threat to papaya fruit yield leading to huge losses. This study focuses on controlling the fungal pathogens of papaya fruit by isolating the disease control bacteria from the phylloplane of the papaya plant and screening them for antagonism towards the pathogens. The fungal pathogens chosen for this study were Colletotrichum, Fusarium and Rhizopus. The three bacterial isolates showing the maximum diameter for the zone of inhibition against these pathogens were selected for morphological and biochemical characterization. In studies, the isolates were found to be Bacillus and Pseudomonas. Consortium study was conducted between Bacillus and Pseudomonas which showed more efficiency in controlling the growth of fungal pathogens when combined. Fruit assay was then performed to establish these bacterial isolates as biocontrol agents. Papaya fruits were inoculated with fungal pathogens and fungal pathogens along with bacterial isolates. It was observed that the papayas inoculated with bacterial isolates showed a better shelf life than those without. The present study reports the biocontrol ability of the bacteria which can be used as disease control agents.