Factors Affecting the Efficiency of Symbiotic Nitrogen Fixation by Rhizobium
نویسندگان
چکیده
منابع مشابه
Nitrate reduction and nitrogen fixation in symbiotic association Rhizobium-legumes.
The inhibitory effect of nitrate on nitrogenase activity in root nodules of legume plants has been known for a long time. The major factor inducing changes in nitrogenase activity is the concentration of free oxygen inside nodules. Oxygen availability in the infected zone of nodule is limited, among others, by the gas diffusion resistance in nodule cortex. The presence of nitrate may cause chan...
متن کاملSymbiotic Nitrogen Fixation.
Biosphere nitrogen is subjected to rapid turnover, and because it is eventually lost as nitrogen into the atmosphere, its maintenance requires continuous replenishment with reduced nitrogen from atmospheric nitrogen. Biological reduction of nitrogen to ammonia can be performed only by some prokaryotes and is a highly oxygen-sensitive process. The most efficient nitrogen fixers establish a symbi...
متن کاملA phosphate transport system is required for symbiotic nitrogen fixation by Rhizobium meliloti.
The bacterium Rhizobium meliloti forms N2-fixing root nodules on alfalfa plants. The ndvF locus, located on the 1,700-kb pEXO megaplasmid of R. meliloti, is required for nodule invasion and N2 fixation. Here we report that ndvF contains four genes, phoCDET, which encode an ABC-type transport system for the uptake of Pi into the bacteria. The PhoC and PhoD proteins are homologous to the Escheric...
متن کاملThe cin quorum sensing locus of Rhizobium etli CNPAF512 affects growth and symbiotic nitrogen fixation.
Rhizobium etli CNPAF512 produces an autoinducer that inhibits growth of Rhizobium leguminosarum bv. viciae 248 and activates the Agrobacterium tumefaciens tra reporter system. Production of this compound in R. etli is dependent on two genes, named cinR and cinI, postulated to code for a transcriptional regulator and an autoinducer synthase, respectively. NMR analysis of the purified molecule in...
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ژورنال
عنوان ژورنال: Pakistan Journal of Biological Sciences
سال: 2002
ISSN: 1028-8880
DOI: 10.3923/pjbs.2002.1277.1293