Linked expression of nap and nos genes in a Bradyrhizobium japonicum 1 mutant with increased N 2 O reductase activity
نویسندگان
چکیده
13 To understand the mechanisms underlying the increased N2O reductase activity in the 14 Bradyrhizobium japonicum 5M09 mutant from enrichment culture under N2O respiration, we 15 analyzed the expression of genes encoding denitrification reductases and regulators. Our 16 results suggest a common regulation of nap (encoding periplasmic nitrate reductase) and nos 17 (encoding N2O reductase). 18
منابع مشابه
Linked expressions of nap and nos genes in a Bradyrhizobium japonicum mutant with increased N(2)O reductase activity.
To understand the mechanisms underlying the increased N2O reductase activity in the Bradyrhizobium japonicum 5M09 mutant from enrichment culture under N2O respiration, we analyzed the expression of genes encoding denitrification reductases and regulators. Our results suggest a common regulation of nap (encoding periplasmic nitrate reductase) and nos (encoding N2O reductase).
متن کاملSymbiotic Bradyrhizobium japonicum reduces N2O surrounding the soybean root system via nitrous oxide reductase.
N(2)O reductase activity in soybean nodules formed with Bradyrhizobium japonicum was evaluated from N(2)O uptake and conversion of (15)N-N(2)O into (15)N-N(2). Free-living cells of USDA110 showed N(2)O reductase activity, whereas a nosZ mutant did not. Complementation of the nosZ mutant with two cosmids containing the nosRZDFYLX genes of B. japonicum USDA110 restored the N(2)O reductase activit...
متن کاملMolybdate-dependent expression of the periplasmic nitrate reductase in Bradyrhizobium japonicum.
The napEDABC genes of Bradyrhizobium japonicum encode the periplasmic nitrate reductase, an Mo-containing enzyme which catalyses the reduction of nitrate to nitrite when oxygen concentrations are limiting. In this bacterium, another set of genes, modABC, code for a high affinity ABC-type Mo transport system. A B. japonicum modA mutant has been obtained that is not capable of growing anaerobical...
متن کاملAnaerobic Reduction of Nitrate to Nitrous Oxide Is Lower in Bradyrhizobium japonicum than in Bradyrhizobium diazoefficiens
When soil oxygen levels decrease, some bradyrhizobia use denitrification as an alternative form of respiration. Bradyrhizobium diazoefficiens (nos+) completely denitrifies nitrate (NO3-) to dinitrogen, whereas B. japonicum (nos-) is unable to reduce nitrous oxide to dinitrogen. We found that anaerobic growth with NO3- as the electron acceptor was significantly lower in B. japonicum than in B. d...
متن کاملThe complete denitrification pathway of the symbiotic, nitrogen-fixing bacterium Bradyrhizobium japonicum.
Denitrification is an alternative form of respiration in which bacteria sequentially reduce nitrate or nitrite to nitrogen gas by the intermediates nitric oxide and nitrous oxide when oxygen concentrations are limiting. In Bradyrhizobium japonicum, the N(2)-fixing microsymbiont of soya beans, denitrification depends on the napEDABC, nirK, norCBQD, and nosRZDFYLX gene clusters encoding nitrate-,...
متن کامل