Competitive fitness and stability of ammonium-excreting Azotobacter vinelandii strains in the soil.
Appl Microbiol Biotechnol
; 108(1): 378, 2024 Jun 18.
Article
em En
| MEDLINE
| ID: mdl-38888816
ABSTRACT
Non-symbiotic N2-fixation would greatly increase the versatility of N-biofertilizers for sustainable agriculture. Genetic modification of diazotrophic bacteria has successfully enhanced NH4+ release. In this study, we compared the competitive fitness of A. vinelandii mutant strains, which allowed us to analyze the burden of NH4+ release under a broad dynamic range. Long-term competition assays under regular culture conditions confirmed a large burden for NH4+ release, exclusion by the wt strain, phenotypic instability, and loss of the ability to release NH4+. In contrast, co-inoculation in mild autoclaved soil showed a much longer co-existence with the wt strain and a stable NH4+ release phenotype. All genetically modified strains increased the N content and changed its chemical speciation in the soil. This study contributes one step forward towards bridging a knowledge gap between molecular biology laboratory research and the incorporation of N from the air into the soil in a molecular species suitable for plant nutrition, a crucial requirement for developing improved bacterial inoculants for economic and environmentally sustainable agriculture. KEY POINTS ⢠Genetic engineering for NH4+ excretion imposes a fitness burden on the culture medium ⢠Large phenotypic instability for NH4+-excreting bacteria in culture medium ⢠Lower fitness burden and phenotypic instability for NH4+-excreting bacteria in soil.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Microbiologia do Solo
/
Azotobacter vinelandii
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Compostos de Amônio
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Alemanha