Bacillus polymyxa and Rahnella aquatilis, the dominant N2-fixing bacteria associated with wheat roots in French soils
| Autor: | Heulin, Thierry, Berge, Odile, Mavingui, Patrick, Gouzoux, L., Hebbar, K.P., Balandreau, Jacques |
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| Přispěvatelé: | Centre National de la Recherche Scientifique (CNRS), ProdInra, Migration |
| Jazyk: | angličtina |
| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | European Journal of Soil Biology European Journal of Soil Biology, Elsevier, 1994, 30, pp.35-42 |
| ISSN: | 1164-5563 |
| Popis: | International audience; In a study of adaptive traits of rhizosphere inhabiting N2-fixing bacteria, 56 strains representative for the diazotrophic population were isolated from the rhizosphere of three week old spring wheat plants (cv. Castan). For the isolation procedure, a medium was used which contained the exudates of sterile plantlets of wheat (the ''spermosphere model''). N2-fixing Bacillus polymyxa and Bacillus circulans were dominant in three out of four French soils studied. The dominant N2-fixing microflora of the fourth soil was a population of Rahnella aquatilis, an enteric bacterium closely related to Enterobacter agglomerans and Erwinia herbicola. The sizes of these N2-fixing populations were between 1 and 5 x 10(5) cfu g-1 dry weight of rhizosphere soil. These two rhizosphere populations differed markedly by two important characters: (1) when associated with plants under gnotobiotic conditions, the average acetylene reduction activity was much higher in Bacillus than in R. aquatilis strains; (2) in vitro, 90% of Bacillus isolates exhibited a clear antagonistic activity against Gaeumannomyces graminis var. tritici (Ggt), the causative agent of the take-all disease of wheat, whereas none of the 25 strains of R. aquatilis tested showed any antogonistic activity. |
| Databáze: | OpenAIRE |
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