Study of ACC deaminase activity of Rhizobacteria isolated from soils of northern Iran

Abstract

IntroductionPlant growth promoting rhizobacteria with ACC deaminase activity can be used for stimulating plant growth under tension situations. This study held to surveyed native bacteria having ACC deaminase activity. Materials and methods: 8 (none) rhizospherial soils were cultured by preparing serial dilution in selective media. The isolates screened by semi quantity assay of determining ACC deaminase in which diagonal colony after inoculation and incubation was measured in first, second and fifth day. The ability of these strains in accdeaminase production was investigated by optical density of bacterial growth in 504nm. ACC deaminase activity was assayed by measuring the production of α-KB. The selected strains recognized by biochemical and microbiological tests and the best strain in production of ACCD was identified by PCR amplification and sequencing of 16s rRNA.. Results: 445 stains were isolated. Then, 17 stains were selected by semi quantity assay. Then, 9 strains belong to Bacillus and Pseudomonas genera and Actinomycete group, were selected based on their abilities in the enzymes production. The study of Acc deaminase activity showed Pseudomonas brassicacearum strain KOT12 belonged to the fluorescent pseudomonad group had highest activity (826/4369 nmol kb/mg pr/h). Discussion and conclusion: Based on high production of ACCD in the selected isolate in comparison with other strains, this strain can be used for PGPR inoculums in the field by optimizing enzyme production and formulation.

Keywords

• Accdeaminase
• ACC
• Selected strains