Pedosphere 24(4): 461--468, 2014
ISSN 1002-0160/CN 32-1315/P
©2014 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Characterization of 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing Pseudomonas spp. in the rhizosphere of salt- stressed canola
A. R. AKHGAR1, M. ARZANLOU2, P. A. H. M. BAKKER3 and M. HAMIDPOUR1
1Department of Soil Science, Vali-e-Asr University of Rafsanjan, Rafsanjan (Iran)
2Department of Soil Science, University of Tabriz, Tabriz (Iran)
3Department of Biology, Plant-Microbe Interactions, Utrecht University, Utrecht (Netherlands)
ABSTRACT
      When exposed to biotic or abiotic stress conditions, plants produce ethylene from its immediate precursor 1-aminocyclopropane-1-carboxylate (ACC), leading to retarded root growth and senescence. Many plant growth-promoting rhizobacteria contain the enzyme ACC deaminase and this enzyme can cleave ACC to form α-ketobutyrate and ammonium, thereby lowering levels of ethylene. The aim of this study was to isolate and characterize ACC deaminase-producing bacteria from the rhizosphere of salt-stressed canola (Brassica napus L.). Out of 105 random bacterial isolates, 15 were able to utilize ACC as the sole source of nitrogen. These 15 isolates were also positive for indole acetic acid production. Phylogenetic analysis based on partial 16S rDNA sequences showed that all isolates belonged to fluorescent Pseudomonas spp. In the canola rhizosphere investigated in this study, Pseudomonas fluorescens was the dominant ACC deaminase-producing species. Cluster analysis based on BOX-A1R-based repetitive extragenic palindromic-polymerase chain reaction (BOX-PCR) patterns suggested a high degree of genetic variability in ACC deaminase-producing P. fluorescens strains. The presence of indigenous ACC-degrading bacteria in the rhizosphere of canola grown in saline soils indicates that these bacteria may contribute to salinity tolerance.
Key Words:  BOX-A1R-based repetitive extragenic palindromic-polymerase chain reaction (BOX-PCR), ethylene, indole acetic acid, phylogenetic analysis, plant growth-promoting rhizobacteria (PGPR), Pseudomonas fluorescens
Citation: Akhgar, A. R., Arzanlou, M., Bakker, H. M. and Hamidpour, M. 2014. Characterization of 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing Pseudomonas spp. in the rhizosphere of salt- stressed canola. Pedosphere. 24(4): 461-468.
View Full Text



Copyright © 2024 Editorial Committee of PEDOSPHERE. All rights reserved.
Address: P. O. Box 821, 71 East Beijing Road, Nanjing 210008, China    E-mail: pedosphere@issas.ac.cn
Technical support: Beijing E-Tiller Co.,Ltd.