Symbiotic Deficiencies Associated with a coxWXYZ Mutant of Bradyrhizobium japonicum
AUTOR(ES)
Surpin, Marci Ann
FONTE
American Society for Microbiology
RESUMO
The terminal oxidase complexes encoded by coxMNOP and coxWXYZ were studied by analysis of mutations in each of the two oxidases. Carbon monoxide difference spectra obtained from membranes of coxMNOP mutant bacteroids were like those obtained for the wild type, whereas bacteroid membranes of a coxWXYZ mutant were deficient in CO-reactive cytochrome b. Experiments involving cyanide inhibition of oxidase activity were consistent with the conclusion that the coxX mutant is deficient in a membrane-associated O2-binding component. The viable cell number (bacteria that could be recultured from crushed nodules) was 20 to 29% lower for the coxX mutant than for the wild-type or the CoxN− strain. In three separate greenhouse studies, nodules of a coxX mutant had significantly lower (28 to 34% less) acetylene reduction rates than the wild-type nodules did, and plants inoculated with a double mutant (coxMNOP coxWZYZ) had rates 30% lower than those of wild-type-inoculated plants.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=91028Documentos Relacionados
- Mutant Strain of Bradyrhizobium japonicum with Increased Symbiotic N2 Fixation Rates and Altered Mo Metabolism Properties †
- Conservation of symbiotic nitrogen fixation gene sequences in Rhizobium japonicum and Bradyrhizobium japonicum.
- Symbiotic Expression of Cosmid-Borne Bradyrhizobium japonicum Hydrogenase Genes †
- Enhanced Nitrogen Fixation in a Rhizobium etli ntrC Mutant That Overproduces the Bradyrhizobium japonicum Symbiotic Terminal Oxidase cbb3
- Isolation and Characterization of a Competition-Defective Bradyrhizobium japonicum Mutant