Azospirillum

Cloning of Azospirillum irakense genes encoding pectinolytic activity. 

In this study we have isolated and partially characterised the Azospirillum irakense genes that encode for pectate lyase and polygalacturonase activity. 

Establishment of inoculated Azospirillum spp. in the rhizosphere and in roots of field grown wheat and sorghum. Plant Soil 90 35-46. 

Halsall, D M., Gibson, A.H., 1985. Cellulose decomposition and associated nitrogen fixation by mixed cultures of Cellulomonas gelida and Azospirillum species or Bacillus maceratis. Appl. Environ. Microbiol 50 1021-1026. 

Khammas, K M. and Kaiser, P., 1991. Characterization of a pectinolytic activity in Azospirillum irakense. Plant and soil 137, 75-79. 

Khammas, K. M., Ageron, E., Grimont, P A D. and Kaiser, P., 1989. Azospirillum irakense sp. nov., a nitrogen-fixing bacterium associated with rice roots and rhizosphere soil. Res. Microbiol. 140, 679-693. 

Plazinski, J. and Rolfe, B.G.. 1985. Analysis of pectinolytic activity of Rhizohhim and Azospirillum strains isolated from Trifolium repens. J. Plant Physiol. 120, 181-187. 

Reinhold, B., Hurek, T., Fendrik, I., Pot, B., Gillis, M., Kersters, K., Thielemans, S. and De Ley, J. 1987. Azospirillum halopraeferans sp. nov., a nitrogen-fixing organism associated with roots of Kallar grass (Leplochloa fusca (L.) Kunth.). Int. J. Syst. Bacteriol 37 43-51. 

Tarrand, J.J, Krieg, NR and Dobereiner, J. 1978. A taxonomic study of the Spirillum Up(ferum group, with description of a new genus. Azospirillum gen. nov., and two species Azospirillum lipoferum (Beijerinck) sp. nov. and Azospitillum hrasilense sp. nov. Can. J. Microbiol. 24 967-980. 

Vanstockem,M., Michiels, K., Vanderleyden, J. and Van Gool, A., 1987 Transposon mutagenesis of Azospirillum hrasilense and Azospirillum lipoferum, physical analysis of Tn5 and lr 5-moh insertion mutants. Appl. Environ. Microbiol. 53 410-415. 

The presence of microorganisms in the rhizosphere has been shown to increa.se root exudation (58,61-65). This stimulation of exudation has been shown to occur in the pre.sence of free-living bacteria such as Azospirillum spp. and Azotobacter spp. (66,67) and in the presence of symbiotic organisms such as mycorrhizae (68,69). Increased root exudation has also been shown to be species-specific for example Meharg and Killham (65) found that metabolites produced by Pseudomonas aeru/ inosa stimulated a 12-fold increase in C-labeled exudates by perennial ryegrass. However, under the same conditions, metabolites from an Arthro-bacter species had no effect on root exudation. 

G. Lopez-de-Victoria and C. R. Lovell, Chemotaxis of Azospirillum species to aromatic compounds. Applied and Environmental Microbiology 59 2951 (1993). 

Y. Bashan and G. Holguin, Root-to-root travel of the beneficial bacterium Azospirillum brasilense, Applied and Environmental Microbiology 60 2120 (1994). 

Y. Bashan and G. Holguin, Azospirillum-p ant relationships Environmental and physiological advances (1990-1996), Canadian Journal of Microbiology 43 103 (1997). 

Y. Bashan, M. Singh, and H. Levanony, H. (1989). Contribution of Azospirillum brasilense Cd to growth of tomato seedlings is not through nitrogen fixation. Canadian Journal of Botany (57 1317. 

Azospirillum Capable of fixation, commonly associated with grasses... 

Condensation products of DHB (which usually is found also in the fermentation broth) with amino acids were reported, viz. with glycine ixom Bacillus subtilis (164) named subsequently itoic acid (282) with serine from Escherichia coli (261) and Klebsiella oxytoca (196) with threonine from Klebsiella oxytoca (196) and Rhizobium spp. (275, 327) with arginine from Pseudomonas stutzeri (62) with glycine and threonine from Rhizobium sp. (240) with threonine and lysine as well as with leucine and lysine from Azospirillum lipoferum (312, 320). In most cases the isolate (sometimes designated as being a siderophore) was hydrolyzed and the constituents were determined by paper chromatography. The relative amounts of the constituents, the chiralities of the amino acids and the molecular mass of the isolate have not been determined. Hence it is not known whether condensation products of the enterobactin type exist. 

Azospirillum brasilense under iron starvation produces spirilobactin. Hydrolysis yields DHB, ornithine, and serine of unknown chirality in a ratio of 1 1 1. The molecular mass was not determined and hence it is not known whether spirilobactin forms a (cyclic) trimer. Iron uptake was studied with the Fe " complex (70). 

Bachhawat AK, Ghosh S (1987) Iron Transport in Azospirillum brasiliense Role of the Siderophore Spirilobactin. J Gen Microbiol 133 1759... 

Saxena B, Modi M, Modi VV (1986) Isolation and Characterization of Siderophores from Azospirillum lipoferum D-2. J Gen Microbiol 132 2219... 

Shah S, Rao KK, Desai A (1993) Production of Catecholate Type of Siderophores by Azospirillum lipoferum M. Indian J Exp Biol 31 41... 

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