Population Density and Identification of Fluorescent Pseudomonads Associated with Rhizosphere of Wheat

Document Type : Research Paper

Authors

1 PhD student of Soil Science at Tarbiat Modares Univ

2 Prof. at Mazandaran Univ

3 Members of Scientific Staff at Soil and Water Research Institute

4 Prof. at Tarbiat Modares Univ

5 Members of Scientific Staff at Soil and Water Research Institute, respectively

Abstract

During the last decade, much research has been directed towards the potential use of plant growth-promoting rhizobacteria (PGPR). Among the non-symbiotic rhizobacteria, much attention has been given to fluorescent pseudomonas spp., from which many effective inoculants have been prepared. Fluorescent pseudomonads with respect to their ability to produce siderophores and other plant growth promoting characteristics are of first priority for researchers. In order to isolate and identify native pseudomonas strains, 52 soil samples were collected from different locations representing rhizosphere of wheat and were assessed in terms of pseudomonas bacteria. Two hundred and one strains were isolated with King'B medium as fluorescent pseudomonads. The populations of these bacteria ranged between 1.51*105 to 6*108 cfu (colony forming unit) per gram soil. To evaluate protein pattern, the isolates were compared by electrophoresis of soluble proteins on polyacrylamide gel. The isolates were classified into 16 electrophoretic protein-polymorphic types based on their protein patterns in SDS-PAGE. The results of physiological and biochemical tests showed that Pseudomonas putida making up 52.73% of the total strains was the dominant genus in the wheat rhizosphere while 44.27 and 3 % of isolates consisted of P. fluorescens and P. aeruginosa, respectively. Therefore, owing to effective colonization of putida and fluorescens strains on wheat rhizosphere, the isolates may be good candidates for making PGPR inoculants.

Keywords


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