الفهرس | Only 14 pages are availabe for public view |
Abstract The objectives of the present investigation were including five items: (a) Isolation and screening of antagonistic fluorescent pseudomonads from root samples of different crops. (b) Phenotypic characterization of antagonistic fluorescent pseudomonads by biochemical traits. (c) Functional traits (extracellular fungal cell wall degrading enzymes, secondary metabolites, plant growth promoting traits, genes that encode specific functions of antibiotic production). (d) Genetic characterization of antagonistic fluorescent pseudomonads by rpob. (e) Pot experiments were carried out to evaluate the role of the efficient Pseudomonas strains in promotion of bean plant growth and biocontrol of soil-borne pathogen. (t) Effect of different carrier material type (rock phosphate, perlite, bentonite, vermiculite, and their combination on populations of bacteria. A total of 200 strains of fluorescent pseudomonads were isolated from root samples of different crops. Thirty four strains showed a broadspectrum antifungal activity towards phytopathogenic fungi IRhizoctonia solani AG 2-2, Fusarium solani and Pythium arrhenomanes). Based on the antagonistic potential, twenty isolates of fluorescent pseudomonads were studied In detai 1. Antagonistic fluorescent pseudomonads were identified by molecular method to five major groups being group ] was formed by 3 strains of Pseudomonas palleroniana and 1 strain of Pseudomonas moraviensis, group 2 was formed by 1 strain Pseudomonas anguilliseptica, group 3 was formed by strains, representing the major group, 2 strains of Pseudomonas entomophila,l strain of Pseudomonas parafulva, 3 strains of Pseudomonas plecoglossicida, one strain of Pseudomonas mosselii and 5 strains of Pseudomonas putida, group 4 was formed by 1 strain of Pseudomonas argentinensis and group 5 was formed by 2 strains of Pseudomonas corrugate. Comparison of inoculated and non inoculated plants in infested soil showed that antagonistic fluorescent pseudo monads gave great support to host plants. Beans plants inoculated with antagonistic fluorescent pseudomonads were significantly higher than all treatments. The effect of different carrier material type on populations of bacteria appeared that vermiculite was the best carrier for Pseudomonas putida SAW19 strain. |