Document Type : Research Paper

Authors

• M.H Rasouli Sadaghiani
• M.J Malakouti
• K Khavazi
• M Ghannadi Maragheh

Abstract

The objective of this investigation was to determine the potentials of some indigenous fluorescent Pseudomonads for siderophore production and their effects on ⁶⁵Zn absorption in 2005. For this purpose, 201 strains of Pseudomonas putida, P. fluorescens, and P. aeruginosa were isolated from different locations representing rhizosphere of wheat (Triticum aestivum L.). The potentials of these strains for siderophore production were evaluated by chrome azorel-S assay (CAS blue agar) through color change. High siderophore producing super-strains were selected for the extraction of siderophores. These isolates were grown in SSM (standard succinate medium) for 72 hrs at 28°C. The bacterial cells  
were removed by centrifugation (10000 g for 20 minutes) and the supernatant was filtered through filter membrane (0.22 μ) and used as the source of siderophore source. The evaluations of Zn uptake and translocation were carried out with the complexes of bacterial siderophores and ⁶⁵Zn compared with the standard siderophore Desferrioxamine in a randomized complete block design with three replications. This experiment was conducted on two wheat genotypes different in Zn-efficiency under hydroponic condition. The results revealed that among the three most effective siderophores producing strains considered, the P. putida produced a siderophore complex that showed efficiencies of 83% compared with the standard siderophore (DFOB) in the uptake of Zn and was statistically in the same group as the control. The effect of bacterial siderophores in the uptake of labeled ⁶⁵Zn by wheat was significant, indicating that the chemical structures of the siderophores from different strains were different. The effects of wheat variety on ⁶⁵Zn translocation to shoots was also significant, where the efficient Tabasi variety contained 46% more Zn in shoots than the inefficient Yavarous variety. It was concluded that the siderophore complex from P. putida was the most effective in translocation Zn to shoots, particularly in efficient Tabasi genotype. Siderophore effectiveness in Zn availability decreased in the order of Sid-DFOB> Sid-P. putida>Sid-P. fluorescens> Sid-P. aeruginosa. Due to the availability of P. putida in absorbing Zn, the siderophores of this group of bacteria can be named as zincophore.
 

Highlights

 

 

1. 18.              L. L. Barton, and B. C. Hemming “Iron chelation in plants and soil microorganisms,” Academic Press, USA (1993).

 

 

	29

 

 

1. 19.              G. R. Cline, C. P. Reid, P. E. Powell and P. J. Szaniszlo “Effects of a hydroxamate  siderophore on iron absorption by sunflower and sorghum,” Plant Physiol., 76: 36–39 (1984).

 

1. 20.              V. Romheld and H. Marschner “Genotypical differences among graminaceous species in release of phytosiderophores and uptake of iron phytosiderophores,” Plant and Soil, 123: 147-153 (1990).
2. 21.              A. Walter, V. Romheld, H. Marschner, and D. E. Crowley “Iron nutrition of cucumber and maize: Effect of Pseudomonas putida YC3 and its siderophore,” Soil Biol. Biochem.., 26: 1023-1031 (1994b).

 

1. 22.              H. Marschner “Mineral nutrition of higher plants,” Academic Press, London. (1995).

 

1. 23.              Z. Yehuda, M. Shenker, V. Romheld, H. Marschner, Y. Hadar, and Y. Chen “The role of ligand exchange in the uptake of iron from microbial siderophores by gramineous plants,” Plant Physiol., 112: 1273-1280 (1996).

 

1. 24.              A. Sharma, B. N. Johri, A. K. Sharma and B. R. Glick “Plant growth-promoting bacterium Pseudomonas sp. Strain GRP3 influences iron acquisition in Mung bean,” Soil Biol. Biochem., 35: 887-894 (2003).

 

1. 25.              N. W. Schaad “Laboratory guide for identification of plant phathogenic bacteria,” 3rd Ed. APS Press (2001).

 

1. 26.              D. B. Alexander and D. A. Zuberer “Use of chrome azurol S reagents to evaluate siderophore production by rhizosphere bacteria,” Biol. Fertil. Soils, 12: 39-45 (1991).

 

1. 27.              I. Tolay, B. Erenoglu, V. Romheld, H. J. Braun and I. Cakmak “Phytosiderophore release in Aegilops tauschii and Triticum species under zinc and iron deficiencies,” J. Exp. Bot., 52: 1093-1099 (2001).

 

1. 28.              G. A. Johnson., A. Lopez and N. V. Foster “Reduction and transport of Fe from siderophores,” Plant and Soil, 241: 27–33 (2002).

 

1. 29.              B. Schwyn, and J. B. Neilands “Universal chemical assay for the detection and determination of siderophores. Anal,” Biochem, 160: 47-56 (1987).

 

1. 30.              A. M. F. Milagres, A. Machuca, and D. Napoleao “Detection of siderophore production from several fungi and bacteria by a modificaction of chrome azurol S (CAS) agar plate assay,” J. Microbiol. Methods, 37: 1-6 (1999).

 

1. 31.              D. E., Crowley, C. P. P. Reid, and P. J. Szaniszlo “Utilization of microbial siderophores in iron acquisition by oat,” Plant Physiol., 87: 680-685 (1988).

 

1. 32.  M. Shenker, Y. Hader, and Y. Chen “Kinetics of iron complexing and exchange in solutions by rhizoferrin, a fungal siderophore,” Soil Sci. Soc. Am. J., 63: 1681-1687 (1999).

 

Keywords

• Plant Growth-Promoting Rhizobacteria (PGPR)
• Fluorescent Pseudomonads
• 65Zn
• Siderophore and Zincophore