Differential expression of hydrogen uptake (hup) genes in vegetative and symbiotic cells of Rhizobium leguminosarum

1990 ◽  
Vol 221 (3) ◽  
pp. 363-370 ◽  
Author(s):  
Jose M. Palacios ◽  
Jesús Murillo ◽  
Antonio Leyva ◽  
Gary Ditta ◽  
Tomás Ruiz-Argüeso
Keyword(s):  
Differential Expression ◽  
Rhizobium Leguminosarum ◽  
Hydrogen Uptake ◽  
Hup Genes

Organization and Expression of Hydrogen-Uptake (hup) Genes of Rhizobium Leguminosarum

1988 ◽  
pp. 175-181
Author(s):  
J. Palacios ◽  
A. Leyva ◽  
G. Ditta ◽  
T. Ruiz-Argüeso
Keyword(s):  
Rhizobium Leguminosarum ◽  
Hydrogen Uptake ◽  
Hup Genes

Genetic engineering in agriculture: hydrogen uptake (hup) genes

1980 ◽  
Vol 5 (6) ◽  
pp. 167-170 ◽  
Author(s):  
S.T. Lim ◽  
K. Andersen ◽  
R. Tait ◽  
R.C. Valentine
Keyword(s):  
Genetic Engineering ◽  
Hydrogen Uptake ◽  
Hup Genes

scholarly journals Genetic organization of the hydrogen uptake (hup) cluster from Rhizobium leguminosarum.

1990 ◽  
Vol 172 (3) ◽  
pp. 1647-1655 ◽  
Author(s):  
A Leyva ◽  
J M Palacios ◽  
J Murillo ◽  
T Ruiz-Argüeso
Keyword(s):  
Rhizobium Leguminosarum ◽  
Hydrogen Uptake ◽  
Genetic Organization

scholarly journals Host-Dependent Expression of Rhizobium leguminosarum bv. viciae Hydrogenase Is Controlled at Transcriptional and Post-Transcriptional Levels in Legume Nodules

2008 ◽  
Vol 21 (5) ◽  
pp. 597-604 ◽  
Author(s):  
Belén Brito ◽  
Annita Toffanin ◽  
Rosa-Isabel Prieto ◽  
Juan Imperial ◽  
Tomás Ruiz-Argüeso ◽  
...  
Keyword(s):  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Gene Promoter ◽  
Hydrogenase Activity ◽  
Transcription Analysis ◽  
Nickel Binding ◽  
Level Of Activity ◽  
Structural Subunit ◽  
Hup Genes ◽  
Related Proteins

The legume host affects the expression of Rhizobium leguminosarum hydrogenase activity in root nodules. High levels of symbiotic hydrogenase activity were detected in R. leguminosarum bacteroids from different hosts, with the exception of lentil (Lens culinaris). Transcription analysis showed that the NifA-regulated R. leguminosarum hydrogenase structural gene promoter (P1) is poorly induced in lentil root nodules. Replacement of the P1 promoter by the FnrN-dependent promoter of the fixN gene restored transcription of hup genes in lentil bacteroids, but not hydrogenase activity. In the PfixN-hupSL strain, additional copies of the hup gene cluster and nickel supplementation to lentil plants increased bacteroid hydrogenase activity. However, the level of activity in lentil still was significantly lower than in pea bacteroids, indicating that an additional factor is impairing hydrogenase expression inside lentil nodules. Immunological analysis revealed that lentil bacteroids contain reduced levels of both hydrogenase structural subunit HupL and nickel-binding protein HypB. Altogether, results indicate that hydrogenase expression is affected by the legume host at the level of both transcription of hydrogenase structural genes and biosynthesis or stability of nickel-related proteins HypB and HupL, and suggest the existence of a plant-dependent mechanism that affects hydrogenase activity during the symbiosis by limiting nickel availability to the bacteroid.

scholarly journals Nickel Availability and hupSL Activation by Heterologous Regulators Limit Symbiotic Expression of theRhizobium leguminosarum bv. Viciae Hydrogenase System in Hup− Rhizobia

2000 ◽  
Vol 66 (3) ◽  
pp. 937-942 ◽  
Author(s):  
Belén Brito ◽  
Jorge Monza ◽  
Juan Imperial ◽  
Tomás Ruiz-Argüeso ◽  
Jose Manuel Palacios
Keyword(s):  
Transcriptional Activation ◽  
Sinorhizobium Meliloti ◽  
Rhizobium Leguminosarum ◽  
Transcriptional Regulator ◽  
Hydrogen Uptake ◽  
Hydrogenase Activity ◽  
Structural Genes ◽  
Mesorhizobium Loti ◽  
Genes Expression ◽  
Relevant Factors

ABSTRACT A limited number of Rhizobium andBradyrhizobium strains possess a hydrogen uptake (Hup) system that recycles the hydrogen released from the nitrogen fixation process in legume nodules. To extend this ability to rhizobia that nodulate agronomically important crops, we investigated factors that affect the expression of a cosmid-borne Hup system from Rhizobium leguminosarum bv. viciae UPM791 in R. leguminosarumbv. viciae, Rhizobium etli, Mesorhizobium loti, and Sinorhizobium meliloti Hup− strains. After cosmid pAL618 carrying the entire hup system of strain UPM791 was introduced, all recipient strains acquired the ability to oxidize H2 in symbioses with their hosts, although the levels of hydrogenase activity were found to be strain and species dependent. The levels of hydrogenase activity were correlated with the levels of nickel-dependent processing of the hydrogenase structural polypeptides and with transcription of structural genes. Expression of the NifA-dependent hupSL promoter varied depending on the genetic background, while the hyp operon, which is controlled by the FnrN transcriptional regulator, was expressed at similar levels in all recipient strains. With the exception of theR. etli-bean symbiosis, the availability of nickel to bacteroids strongly affected hydrogenase processing and activity in the systems tested. Our results indicate that efficient transcriptional activation by heterologous regulators and processing of the hydrogenase as a function of the availability of nickel to the bacteroid are relevant factors that affect hydrogenase expression in heterologous rhizobia.

scholarly journals Engineering the Rhizobium leguminosarum bv. viciae Hydrogenase System for Expression in Free-Living Microaerobic Cells and Increased Symbiotic Hydrogenase Activity

2002 ◽  
Vol 68 (5) ◽  
pp. 2461-2467 ◽  
Author(s):  
B. Brito ◽  
J. M. Palacios ◽  
J. Imperial ◽  
T. Ruiz-Argüeso
Keyword(s):  
Time Course ◽  
Rhizobium Leguminosarum ◽  
Active Form ◽  
Hydrogen Uptake ◽  
Immunoblot Analysis ◽  
Living Cells ◽  
Culture Conditions ◽  
Hydrogenase Activity ◽  
Free Living ◽  
Cell Fractions

ABSTRACT Rhizobium leguminosarum bv. viciae UPM791 induces hydrogenase activity in pea (Pisum sativum L.) bacteroids but not in free-living cells. The symbiotic induction of hydrogenase structural genes (hupSL) is mediated by NifA, the general regulator of the nitrogen fixation process. So far, no culture conditions have been found to induce NifA-dependent promoters in vegetative cells of this bacterium. This hampers the study of the R. leguminosarum hydrogenase system. We have replaced the native NifA-dependent hupSL promoter with the FnrN-dependent fixN promoter, generating strain SPF25, which expresses the hup system in microaerobic free-living cells. SPF25 reaches levels of hydrogenase activity in microaerobiosis similar to those induced in UPM791 bacteroids. A sixfold increase in hydrogenase activity was detected in merodiploid strain SPF25(pALPF1). A time course induction of hydrogenase activity in microaerobic free-living cells of SPF25(pALPF1) shows that hydrogenase activity is detected after 3 h of microaerobic incubation. Maximal hydrogen uptake activity was observed after 10 h of microaerobiosis. Immunoblot analysis of microaerobically induced SPF25(pALPF1) cell fractions indicated that the HupL active form is located in the membrane, whereas the unprocessed protein remains in the soluble fraction. Symbiotic hydrogenase activity of strain SPF25 was not impaired by the promoter replacement. Moreover, bacteroids from pea plants grown in low-nickel concentrations induced higher levels of hydrogenase activity than the wild-type strain and were able to recycle all hydrogen evolved by nodules. This constitutes a new strategy to improve hydrogenase activity in symbiosis.

scholarly journals Conserved Plasmid Hydrogen-Uptake (hup)-Specific Sequences within Hup+Rhizobium leguminosarum Strains

1987 ◽  
Vol 53 (10) ◽  
pp. 2539-2543 ◽  
Author(s):  
Antonio Leyva ◽  
José M. Palacios ◽  
Tomás Ruiz-Argüeso
Keyword(s):  
Rhizobium Leguminosarum ◽  
Hydrogen Uptake ◽  
Specific Sequences
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