Abstract
Inter-root movement and dispersion of the beneficial bacterium Azospirillum brasilense were monitored in root systems of wheat seedlings growing in the field and in growth chamber soil trays. Two strains were used, a motile wild-type strain (Cd, mot+) and a motility deficient strain (mot−), which was derived from the Cd strain. Root colonization by two wild-type strains (Cd and Sp-245) was studied in 64 plant species growing in pots in the greenhouse. The two wild-type strains of A. brasilense were capable of colonizing all tested plant species. In soil trays and in the field, mot+ cells moved from inoculated roots to non-inoculated roots of either wheat plants or weeds growing in the same field plot, but the mot− strain did not move toward non-inoculated roots of either plant species. In the field, both mot+ and mot− strains of A. brasilense survived well in the rhizosphere of wheat for 30 days, but only mot+ moved between different weeds, regardless of the species, botanical family, or whether they were annuals or perennials. In plant-free, water-saturated soils, either in columns or in the field, both strains remained at the inoculation site and did not move.
It is proposed (a) that A. brasilense is not a plant-specific bacterium and that (b) colonization of the entire root system in soil is an active process determined by bacterial motility; it is not plant specific, but depends on the presence of plants.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Baldani VLD, Alvarez de B MA, Baldani JL, Döbereiner J (1986) Establishment of inoculated Azospirillum spp. in the rhizosphere and in roots of field grown wheat and sorghum. Plant Soil 90:35–46
Barak R, Nur I, Okon Y, Henis Y (1982) Aerotactic response of Azospirillum brasilense. J Bacteriol 152:643–649
Bashan Y (1986) Enhancement of wheat roots colonization and plant development by Azospirillum brasilense Cd. following temporary depression of the rhizosphere microflora. Appl Environ Microbiol 51:1067–1071
Bashan Y (1986) Alginate beads as synthetic inoculant carriers for the slow release of bacteria that affect plant growth. Appl Environ Microbiol 51:1089–1098
Bashan Y (1986) Significance of timing and level of inoculation with rhizosphere bacteria on wheat plants. Soil Biol Biochem 18:297–301
Bashan Y, Harrison SK, Whitmoyer RE (1990) Enhanced growth of wheat and soybean plants inoculated with Azospirillum brasilense is not necessarily due to general enhancement of mineral uptake. Appl Environ Microbiol 56:769–775
Bashan Y, Holguin G (1994) Root-to-root travel of the beneficial bacterium Azospirillum brasilense. Appl Environ Microbiol 60: 2120–2131
Bashan Y, Holguin G, Lifshitz R (1993) Isolation and characterization of Plant Growth-Promoting Rhizobacteria. In: Glick BR, Thompson JE, (eds) Methods in plant molecular biology and biotechnology. CRC Press, Boca Raton, Florida, pp 331–345
Bashan Y, Levanony H (1985) An improved selection technique and medium for the isolation and enumeration of Azospirillum brasilense. Can J Microbiol 31:947–952
Bashan Y, Levanony H (1987) Horizontal and vertical movement of Azospirillum brasilense Cd in the soil and along the rhizosphere of wheat and weeds in controlled and field environments. J Gen Microbiol 133:3473–3480
Bashan Y, Levanony H (1988) Adsorption of the rhizosphere bacterium Azospirillum brasilense Cd to soil, sand and peat particles. J Gen Microbiol 134:1811–1820
Bashan Y, Levanony H (1989) Wheat root tips as a vector for passive vertical transfer of Azospirillum brasilense Cd. J Gen Microbiol 135:2899–2908
Bashan Y, Levanony H (1990) Current status of Azospirillum as a challenge for agriculture. Can J Microbiol 36:591–608
Bashan Y, Levanony H, Ziv-Vecht O (1987) The fate of field-inoculated Azospirillum brasilense Cd in wheat rhizosphere during the growing season. Can J Microbiol 33:1074–1079
Bashan Y, Mitiku G, Whitmoyer RE, Levanony H (1991) Evidence that fibrillar anchoring is essential for Azospirillum brasilense Cd attachment to sand. Plant Soil 132:73–83
Bashan Y, Mitiku G, Ziv-Vecht O, Levanony H (1991) Estimation of minimal numbers of Azospirillum brasilense using time-limited liquid enrichment combined with enzyme-linked immunosorbent assay. Soil Biol Biochem 23:135–138
Bashan Y, Ream Y, Levanony H, Sade A (1989) Nonspecific responses in plant growth, yield, and root colonization of noncereal crop plants to inoculation with Azospirillum brasilense Cd. Can J Bot 67:1317–1324
Bashan Y, Singh M, Levanony H (1989) Contribution of Azospirillum brasilense Cd to growth of tomato seedlings is not through nitrogen fixation. Can J Bot 67:2429–2434
Bashan Y, Wolowelsky J (1987) Soil samplers for quantifying microorganisms. Soil Sci 143:132–138
Cohen G (1966) Chemical control handbook. Sifriath Hassadeh Publishers, Tel Aviv, Israel (in Hebrew)
Crossman SM, Hill WA (1987) Inoculation of sweet potato with Azospirillum. HortScience 22:420–422
Del Gallo M, Fendrik I, Hofmann N, Neyra CA, Waschütza S (1991) First steps of interaction between Azospirillum spp. and wheat and rice seedling roots. In: Keel C, Koller B, Défago G (eds) Plant growth-promoting rhizobacteria progress and prospects. IOBC/WPRS Bulletin, Zurich, Switzerland, pp 355–358
De Weger LA, van der Vlugt CIM, Wijfjes AHM, Bakker PAHM, Schippers B, Lugtenberg B (1987) Flagella of a plant-growth-stimulating Pseudomonas fluorescens strain are required for colonization of potato roots. J Bacteriol 169:2769–2773
Fages J (1992) An industrial review of Azospirillum inoculants: formulation and application technology. Symbiosis 13:15–26
Gamo T (1991) Azospirillum spp. from crop roots: a promoter of plant growth. Jpn Agri Res Q 24:253–259
Gamo T, Ahn SB (1991) Growth-promoting Azospirillum spp. isolated from the roots of several non-gramineous crops in Japan. Soil Sci Plant Nut 37:455–461
Grishanin RN, Chalmina II, Zhulin IB (1991) Behavior of Azospirillum brasilense in a spatial gradient of oxygen and in a “redox” gradient of an artificial electron acceptor. J Gen Microbiol 137:2781–2785
Hadas R, Okon Y (1987) effect of Azospirillum brasilense inoculation on root morphology and respiration in tomato seedlings. Biol Fertil Soils 5:241–247
Hall PG, Krieg NR (1983) Swarming of Azospirillum brasilense on solid media. Can J Microbiol 29:1592–1594
Levanony H, Bashan Y (1991) Enumeration and identification of rhizosphere bacteria by advanced immuno techniques. In: Keel C, Koller B, Défago G (eds) Plant growth-promoting rhizobacteria progress and prospects. IOBC/WPRS Bulletin, Zürich, Switzerland, pp 231–237
Levanony H, Bashan Y, Kahana ZE (1987) Enzyme-linked immunosorbent assay for specific identification and enumeration of Azospirillum brasilense Cd. in cereal roots. Appl Environ Microbiol 53:358–364
Mascarua-Esparza MA, Villa-Gonzalez R, Caballero-Mellado J (1988) Acetylene reduction and indoleacetic acid production by Azospirillum isolates from Cactaceous plants. Plant Soil 106:91–95
Misaghi IJ, Olsen MW, Billotte JM, Sonoda RM (1992) The importance of rhizobacterial mobility in biocontrol of bacterial wilt of tomato. Soil Biol Biochem 24:287–293
Okon Y, Labandera-Gonzalez CA (1994) Agronomic application of Azospirillum. In: Ryder MH, Stephens PM, Bowen GD (eds) Improving plant productivity with rhizosphere bacteria. CSIRO Division of Soils, Adelaide, Australia, pp 274–278
Parke JL (1991) Root colonization by indigenous and introduced microorganisms. In: Keister DL, Cregan PB (eds) The rhizosphere and plant growth. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp 33–42
Puente ME, Bashan Y (1993) Effect of inoculation with Azospirillum brasilense strains on the germination and seedling growth of the giant columnar Cardon cactus (Pachycereus pringlei). Symbiosis 15:49–60
Rao PSK, Arunachalam V, Tilak KVBR (1990) Genotype-dependent response to Azospirillum treatment in yield and nitrogenase activity in Brassica juncea L. Curr Sci 59:607–609
Reinhold B, Hurek T, Fendrik I (1985) Strain-specific chemotaxis of Azospirillum spp. J Bacteriol 162:190–195
Sarig S, Kapulnik Y, Nur I, Okon Y (1984) Response of non-irrigated Sorghum bicolor Azospirillum inoculation. Exp Agri 20:59–66
Scher FM, Kloepper JW, Singleton CA (1985) Chemotaxis of fluorescent Pseudomonas spp. to soybean seed exudates in vitro and in soil. Can J Microbiol 31:570–574
Vande Broek A, Michiels J, Van Gool A, Vanderleyden J (1993) Spatial-temporal colonization patterns of Azospirillum brasilense on wheat root surface and expression of the bacteria nifH gene during association. Mol Plant-Microbe Int 6:592–600
Zaady E, Perevolotsky A, Okon Y (1993) Promotion of plant growth by inoculation with aggregated and single cell suspension of Azospirillum brasilense Cd. Soil Biol Biochem 25:819–823
Zhulin IB, Armitage JP (1992) The role of taxis in the ecology of Azospirillum. Symbiosis 13:199–206
Zhulin IB, Armitage JP (1993) Motility, chemokinesis, and methylation-independent chemotaxis in Azospirillum. J Bacteriol 175:952–958
Zohary M (1989) A new analytical flora of Israel. Am Oved Publishers, Tel Aviv, Israel, (in Hebrew)
Author information
Authors and Affiliations
Additional information
Correspondence to: Y. Bashan
Rights and permissions
About this article
Cite this article
Bashan, Y., Holguin, G. Inter-root movement of Azospirillum brasilense and subsequent root colonization of crop and weed seedlings growing in soil. Microb Ecol 29, 269–281 (1995). https://doi.org/10.1007/BF00164890
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00164890