Revertible hydrogen uptake-deficient mutants of Rhizobium japonicum

Lepo, J. E.; Hickok, Ruth E.; Cantrell, Michael A.; Russell, Sterling A.; Evans, Harold J.

doi:10.1128/jb.146.2.614-620.1981

Cited by 56 publications

(31 citation statements)

References 30 publications

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“…Significant increases in plant dry weight and nitrogen content (total Kjeldahls of N per plant) have been reported in legumes inoculated with Rhizobium strains with uptake hydrogenase activity (Hup+) when compared with those lacking uptake hydrogenase (Hup-) (1,21,22,24). Recently, similar results were found in more rigorous studies of soybean and mungbean with Huprevertible mutants of Hup+ Rhizobium strains (11,16).…”

supporting

confidence: 53%

Uptake hydrogenase activity and ATP formation in Rhizobium leguminosarum bacteroids

Nelson¹,

Salminen²

1982

J Bacteriol

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The role of uptake hydrogenase was studied in Rhizobium leguminosarum bacteroids from the nodules of Pisum sativum L. cv. Homesteader. Uptake hydrogenase activity, measured by the 3H2 uptake method, was dependent on C( consumption and was similar to H2 uptake measured by gas chromatography. z Km for 02 of 0.0007 atm (0.0709 kPa) and a Km for H2 of 0.0074 atm (0.7498, kPa) were determined. H2 increased the rate of endogenous respiration by isolates with uptake hydrogenase (Hup+) but had no effect on an isolate lacking uptake hydrogenase (Hup-). A survey of 14 Hup+ isolates indicated a wide range of H2 uptake activities. Four of the isolates tested had activities similar to or higher than those found in two Hup+ Rhizobium japonicum strains. H2 uptake was strongly coupled to ATP formation in only 5 of the 14 isolates. H2 increased the optimal 02 level for C2H2 reduction by 0.01 atm and permitted enhanced C2H2 reduction at 02 levels above the optimum in both a coupled and an uncoupled isolate. At suboptimal 02 concentrations a small enhancement of C2H2 reduction by H2 was seen in two out of three isolates in which H2 oxidation was coupled to ATP formation. Thus, the main function of uptake hydrogenase in R. leguminosarum appears to be in the protection of nitrogenase from 02 damage.

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supporting

confidence: 53%

Uptake hydrogenase activity and ATP formation in Rhizobium leguminosarum bacteroids

Nelson¹,

Salminen²

1982

J Bacteriol

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“…Some Hup-mutants have already been mentioned above. The first Hup-mutants of R. japonicum were described by Lepo et al [91] and Maier [92], both authors using the ability for chemoautotrophic growth as a selection method. Hup mutants of R. japonicum have been isolated, which spontaneously revert to the parent type with a frequency, indicating a single-point mutation [91].…”

Section: The Hydrogenase Genesmentioning

confidence: 99%

Hydrogen metabolism and energy costs of nitrogen fixation

Stam

1987

FEMS Microbiology Letters

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SUMMARYThe high energy costs of biological nitrogen fixation are partly caused by hydrogen production during the reduction of dinitrogen to ammonia. Some nitrogen-fixing organisms can recycle the evolved hydrogen via a membrane-bound uptake hydrogenase. The energetic aspects of hydrogen metabolism and nitrogen fixation are discussed.Studies on both isolated nitrogenase proteins and nitrogen-fixing chemostat cultures show that energy limitation will result in a high hydrogen production by nitrogenase. In plant-Rhizobium symbiosis, the supply of oxygen or photosynthetate is the limiting factor for nitrogen fixation. In both cases, nitrogen fixation is energy-limited, and it is concluded that a large amount of hydrogen is produced during nitrogen fixation in these symbioses.Hydrogen reoxidation yields less energy than the oxidation of endogenous substrates, and therefore expression of hydrogenase under oxygenlimited conditions is energetically unfavourable. Moreover, hydrogen reoxidation can never com-

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“…The 5.9kb hybridization band was observed only in the case of strains NIAES 3135, NIAES 3178, J1B70, 11,12,13,14 and 19). PJ17 contains a single point mutation that lacks H 2 -uptake capacity and is derived from USDA 122 (Lepo et al 1981), and PJ17-1 is a revertant of PJ17 (Drevon et al 1982). Thus, with respect to hup structural genes, both PJ17 and PJ17-1 ought to possess almost the same sequences as USDA 122, although PJ17 is phenotypically a Hup" strain.…”

Section: Resultsmentioning

confidence: 99%

“…e USDA; U.S. Department of Agriculture, NIAES; National Institute of Agro-Environmental Science (Tsukuba, Japan), TFAC; Tokachi Federation of Agricultural Cooperatives (Tokachi, Japan). f Lepo et al (1981), Drevon et al (1982).…”

Section: Methodsmentioning

confidence: 99%

Division of Rhizobitoxine-Producing and Hydrogen-Uptake Positive Strains of <italic>Bradyrhizobium japonicum</italic> by <italic>nifDKE</italic> Sequence Divergence

Minamisawa

1990

Plant and Cell Physiology

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Genomic digests from 25 strains of Bradyrhizobium japonicum, for which the phenotypes have been determined with respect to production of rhizobitoxine, hydrogen uptake (Hup) and composition of extracellular polysaccharide (EPS), were hybridized with probe DNAs of the nifDK and nifE genes of B. japonicum USDA 110. The degree of the estimated base substitution in and around nifDKE clearly divided the strains of B. japonicum into two markedly divergent groups, which were designated as genotype I and II. Moreover, a strict correlation was observed between these genotypes, production of rhizobitoxine and EPS composition. The genotype I strains produced no rhizobitoxine and an EPS composed of glucose, mannose, galactose, 4-Omethyl galactose and galacturonic acid, whereas the genotype II strains produced rhizobitoxine and an EPS composed of rhamnose and 4-O-methyl glucuronic acid. Hup + strains were confined exclusively to the genotype I. Hind III digests of genomic DNAs from the 25 strains were hybridized with probe DNA of structural genes for the uptake hydrogenase from B. japonicum. In 23 wild-type strains, Hup + strains generated a 5.9-kb band that hybridized to the probe under high-stringency conditions, while Hup" strains did not generate the band. These results suggest that the genotypes I and II are two highly divergent evolutionary lines that define a marked division of various phenotypes, such as production of rhizobitoxine, EPS composition and hydrogen uptake.

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Revertible hydrogen uptake-deficient mutants of Rhizobium japonicum

Abstract: We have developed mutants of Rhizobium japonicum which are deficient in H2 uptake capacity (Hup-) and which spontaneously revert to the parent type at a frequency consistent with that of a single-point mutation (ca. 1.0 x 10-9). The

Cited by 56 publications

References 30 publications

Uptake hydrogenase activity and ATP formation in Rhizobium leguminosarum bacteroids

Uptake hydrogenase activity and ATP formation in Rhizobium leguminosarum bacteroids

Hydrogen metabolism and energy costs of nitrogen fixation

Division of Rhizobitoxine-Producing and Hydrogen-Uptake Positive Strains of <italic>Bradyrhizobium japonicum</italic> by <italic>nifDKE</italic> Sequence Divergence

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