Cooperative Action of Rhizobium meliloti Nodulation and Infection Mutants during the Process of Forming Mixed Infected Alfalfa Nodules.
Plant Cell
; 2(2): 139-151, 1990 Feb.
Article
em En
| MEDLINE
| ID: mdl-12354955
ABSTRACT
Alfalfa plants co-inoculated with Rhizobium meliloti nodulation (Nod-) and infection mutants deficient in exopolysaccharide production (Inf-EPS-) formed mixed infected nodules that were capable of fixing atmospheric nitrogen. The formation of infected nodules was dependent on close contact between the inoculation partners. When the partners were separated by a filter, empty Fix- nodules were formed, suggesting that infection thread formation in alfalfa is dependent on signals from the nodulation and infection genes. In mixed infected nodules, both nodulation and infection mutants colonized the plant cells and differentiated into bacteroids. The formation of bacteroids was not dependent on cell-to-cell contact between the mutants. Immunogold/silver staining revealed that the ratio of the two mutants varied considerably in colonized plant cells following mixed inoculation. The introduction of an additional nif/fix mutation into one of the inoculation partners did not abolish nitrogen fixation in mixed infected nodules. The expression of nif DlacZ fusions additionally demonstrated that mutations in the nodulation and infection genes did not prevent the nif genes from being expressed in the mutant bacteroids.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Plant Cell
Assunto da revista:
BOTANICA
Ano de publicação:
1990
Tipo de documento:
Article