title: Involvement of nitric oxide in the inhibition of nitrogenase activity by nitrate in Lotus root nodules.
abstract: Nitrogenase activity, as acetylene-reduction activity (ARA), in Lotus root nodules was clearly inhibited 27h after the addition of nitrate. Nitric oxide (NO) production was detected at that time in nitrate-supplied root nodules using the NO-reactive fluorescent probe diaminofluorescein-2 diacetate. The involvement of NO production in the inhibition of nitrogenase activity by nitrate was investigated using the NO donor sodium nitroprusside (SNP) and the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO). SNP inhibited ARA at 1mM, and c-PTIO suppressed the inhibition of ARA by nitrate. These results suggest that NO is involved in the inhibition of nitrogenase activity by nitrate in Lotus root nodules.
authors.affiliation: Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi 981-8555, Japan. kazukato@alumni.tohoku-university.jp
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Kato
authors.forename: Koki
authors.initials: K
authors.lastname: Kanahama
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kanayama
mesh_terms: D000070116:Lotus / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D009591:Nitrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D053204:Root Nodules, Plant / Q000378:metabolism*
chemical_list: D009566:Nitrates; D009569:Nitric Oxide; D009591:Nitrogenase