Abstract
Background: The objectives of this study were to characterize Pseudomonas rhizospheric strains, that have a biocontrol activity, in rhizosphere soil in Hail province and study their ability to form biofilm.
Methods: Rhizosphere soil samples were collected from rhizosphere of soil plantation areas, to be used for bacteria isolation. The identified bacteria were qualitatively tested for their ability to produce slime and subsequently develop biofilm.
Results: The cultural and biochemical identification techniques, including morphological, biochemical and molecular methods revealed that the antagonistic bacteria- from the distinctive rhizosphere soil samples belong to Pseudomonas genus in particular, P. aeruginosa (PF1a, pf2a, PF-8) and P. putida (PF-7). These identified isolates inhibited Aspergillus niger development with percentage of parasitic growth inhibition greater than (48.095 +/- 2.182)% for P. aeruginosa (pf-8). In addition, these identified isolates were significantly shown to be able to produce exopolysaccharide and subsequently develop biofilm on polystyrene and glass surfaces.
Conclusion: Superior strains of these bio-control and plant growth promoting rhizobacteria will enable for better biological control of fungal and bacterial plant diseases and may reduce chemical pesticide usage. The indigenous strains isolated could potentially have a great impact on controlling plant diseases, in particular, those caused by microorganisms, and could be used as an alternative bio control agents instead of harmful chemical pesticides. Most of the tried microbes produced exopolysaccharides as well as formed biofilm on polystyrene and glass surfaces.