Genetic Fingerprinting of Antimicrobial Fluorescent Pseudomonads Associated with Banana Rhizosphere

In recent years, fluorescent pseudomonads are well recognized for their plant growth promoting and bio-control activities. This study was design to study the distribution of potential antimicrobial fluorescent pseudomonads associated with banana rhizosphere by using ERIC and BOX-PCR fingerprinting. For this purpose, 32 fluorescent pseudomonads were isolated from banana rhizosphere collected from three different major grown banana locations and screened against three fungal phytopathogens. Promising isolates were selected for genetic fingerprinting by using ERIC and BOX-PCR to establish clonal relationship among the antifungal fluorescent pseudomonads. ERIC-PCR fingerprinting was found to be a potential tool to differentiate among the fluorescent and non fluorescent bacterial isolates as compare to BOX-PCR fingerprinting. A subset of 25 antagonistic fluorescent pseudomonads were characterized by ERIC and BOX-PCR and showed a high degree of DNA heterogeneity. Four groups were identified based on ERIC-PCR and three of them showed homogeneity containing fluorescent pseudomonas with a group of non fluorescent bacillus sp (PF 7). A unique band of 450 bp was generated by ERIC-PCR profiling among all the fluorescent isolates, which can be used as a diagnostic tool, whereas non fluorescent bacteria will have an adjacent band of 430 bp, which was absent in all identified fluorescent pseudomonas isolates. Further, 16S rDNA based identification of randomly selected isolates proved that ERIC-PCR fingerprinting is better DNA based tool to differentiate fluorescent pseudomonas with other bacterial isolates. We conclude and recommend ERIC-PCR banding pattern could be potential tool to differentiate among fluorescent and non fluorescent group of bacteria.