Relationship between in vitro enhanced nitrogenase activity of an Azospirillum brasilense Sp7 mutant and its growth-promoting activities in situ.
Curr Microbiol
; 53(1): 43-7, 2006 Jul.
Article
en En
| MEDLINE
| ID: mdl-16775786
ABSTRACT
In this work, we further analyzed an Azospirillum brasilense Sp7 mutant (Sp7Tn5-33) showing a pleiotrophic phenotype due to a Tn5 insertion into an open reading frame of 840 bp (orf280). The deduced amino acid sequence of this region has high similarity to a family of universal stress proteins. Because the most interesting property exhibited by the Sp7Tn5-33 mutant was an enhanced in vitro nitrogen fixation activity, we addressed the question of whether it could benefit the host plant. We found that the increased nitrogenase activity at the free-living state of the mutant bacterium was correlated with an increased production of the nitrogenase reductase protein (NifH), in amounts approximately 1.5 times higher than the wild type. The mutant strain exhibited the same level of auxin production and the same colonization pattern of wheat roots as the wild type. We also observed that Sp7Tn5-33 increased the total plant dry weight, although the N content did not differ significantly between wheat plants inoculated with mutant or wild-type strains.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Azospirillum brasilense
/
Nitrogenasa
País/Región como asunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Curr Microbiol
Año:
2006
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA