RHIZOBIUM SP STRAIN-ORS571 AMMONIUM ASSIMILATION AND NITROGEN-FIXATION
RHIZOBIUM SP STRAIN-ORS571 AMMONIUM ASSIMILATION AND NITROGEN-FIXATION
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DOI：
10.1128/jb.158.3.1144-1151.1984
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发表时间：
1984-01-01
影响因子：
3.2
通讯作者：
LUDWIG, RA
中科院分区：
文献类型：
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作者：
DONALD, RGK;LUDWIG, RA
在所研究的根瘤菌中，只有根瘤菌菌株ORS 571在N2作为唯一N源上明确生长。在ORS 571中，只有谷氨酰胺合成酶（GS）-谷氨酸合成酶（GOGAT）途径同化NH 4+。ORS 571表现出该途径的2个独特的生理学方面：ORS 571仅具有GS I，而研究的所有其他根瘤菌科具有GS I和GS II，并且存在NADPH和NADH依赖性GOGAT活性。ORS 571 GS影响和NADPH-GOGAT影响的突变株在培养物和植物[长喙田菁]中的NH 4+同化（Asm-）和N2固定（Nif-）中有缺陷; NADH-GOGAT突变体为Asm-但Nif+。类杆菌GS活性基本为零，表明共生NH 4+输出。研究了谷氨酰胺、NH ~（4+）、蛋氨酸亚砜亚胺和重氮氧正亮氨酸对固氮酶诱导的生理效应，结果表明它们对胞内谷氨酰胺库具有调节作用。
Among rhizobia studied, only Rhizobium sp. strain ORS571 grew unambiguously on N2 as sole N source. In ORS571, only the glutamine synthetase (GS)-glutamate synthase (GOGAT) pathway assimilated NH4+. ORS571 exhibited 2 unique physiological aspects of this pathway: ORS571 had only GS I, whereas all other Rhizobiaceae studied had GS I and GS II, and NADPH- and NADH-dependent GOGAT activities were present. ORS571 GS-affected and NADPH-GOGAT-affected mutant strains were defective in NH4+ assimilation (Asm-) and N2 fixation (Nif-) in culture and in plants [Sesbania rostrata]; NADH-GOGAT mutants were Asm- but Nif+. Bacteroid GS activity was essentially nil, suggesting symbiotic NH4+ export. Physiological studies on effects of glutamine, NH4+, methionine sulfoximine and diazo-oxo-norleucine on nitrogenase induction in culture implied a regulatory role for the intracellular glutamine pool.