Screening and characterization of Rhizobacteria antagonistic to Pseudomonas syringae causing bacterial canker of stone fruits in Punjab and KPK

摘要

Several bacteria colonize plant roots but few of them promote plant growth directly or indirectly are termed as plant growth-promoting rhizobacteria (PGPR). Current study was conducted to isolate rhizobacterial isolates antagonistic to Pseudomonas syringae causing bacterial canker of the stone fruits(apricot, peach and plum) growing in the areas of Punjab and Khyber Pakhtoonkhwa (KPK) provinces of Pakistan. A total of 80 (later pooled to get 16) soil samples were collected from the rhizosphere of apricot, peach and plum and 185 isolates were obtained. Out of 185 rhizobacterial isolates, 10 isolates showed greater potential ( 20 mm zone of inhibition) during in vitro antagonistic activity against P. syringae, and were selected for their morphological and biochemical characterization. Among antagonistic isolates, 6 responded negatively and 4 positively to Gram’s straining. All the antagonistic isolates possessed one or more growth promoting character(s) such as siderophore production, phosphate solubilization, ammonia production and hydrogen cyanide (HCN) production. Six isolates were positive to fluorescence production. Enzymatic activity was exhibited by 8 isolates, during their catalase and lipase activity. Therefore present study suggested that isolates having antagonistic potential as well as plant growth promoting characteristics can be used as bio-protectant/bio-fertilizer to enhance plant growth in stone fruits.