scholarly journals Corrigendum: A GMC Oxidoreductase GmcA Is Required for Symbiotic Nitrogen Fixation in Rhizobium leguminosarum bv. viciae

2021 ◽  
Vol 12 ◽  
Author(s):  
Qian Zou ◽  
Sha Luo ◽  
Hetao Wu ◽  
Donglan He ◽  
Xiaohua Li ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Gmc Oxidoreductase

scholarly journals Antioxidant ability of glutaredoxins and their role in symbiotic nitrogen fixation in Rhizobium leguminosarum bv. viciae 3841

2020 ◽  
Author(s):  
Qian Zou ◽  
Yanlin Zhou ◽  
Guojun Cheng ◽  
Yang Peng ◽  
Sha Luo ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Quantitative Proteomics ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Proteome Analysis ◽  
Wild Type ◽  
Triple Mutant ◽  
Antioxidant Proteins ◽  
Mixed Disulfides ◽  
Nodule Symbiosis

Glutaredoxins (Grx) are redoxin family proteins that reduce disulfides and mixed disulfides between glutathione and proteins. Rhizobium leguminosarum bv. Viciae 3841 contains three genes coding for glutaredoxins: RL4289 (grxA) codes for a dithiolic glutaredoxin, RL2615 (grxB) codes for a monothiol glutaredoxin, while RL4261 (grxC) codes for a glutaredoxin-like NrdH protein. We generated mutants interrupted in one, two, or three glutaredoxin genes. These mutants had no obvious differences in growth phenotypes from the wild type RL3841. However, while a mutant of grxC did not affect the antioxidant or symbiotic capacities of R. leguminosarum, grxA-derived or grxB mutants decreased antioxidant and nitrogen fixation capacities. Furthermore, grxA mutants were severely impaired in rhizosphere colonization, and formed smaller nodules with defects of bacteroid differentiation, whereas nodules induced by grxB mutants contained abnormally thick cortices and prematurely senescent bacteroids. The grx triple mutant had the greatest defect in antioxidant and symbiotic capacities of R. leguminosarum and quantitative proteomics revealed it had 56 up-regulated and 81 down-regulated proteins relative to wildtype. Of these proteins, twenty-eight are involved in transporter activity, twenty are related to stress response and virulence, and sixteen are involved in amino acid metabolism. Overall, R. leguminosarum glutaredoxins behave as antioxidant proteins mediating root nodule symbiosis. IMPORTANCE Glutaredoxin catalyzes glutathionylation/deglutathionylation reactions, protects SH-groups from oxidation and restores functionally active thiols. Three glutaredoxins exist in R. leguminosarum and their properties were investigated in free-living bacteria and during nitrogen-fixing symbiosis. All the glutaredoxins were necessary for oxidative stress defense. Dithiol GrxA affects nodulation and nitrogen fixation of bacteroids by altering deglutathionylation reactions, monothiol GrxB is involved in symbiotic nitrogen fixation by regulating Fe-S cluster biogenesis, and GrxC may participate in symbiosis by an unknown mechanism. Proteome analysis provides clues to explain the differences between the grx triple mutant and wild-type nodules.

scholarly journals Succinate Transport Is Not Essential for Symbiotic Nitrogen Fixation by Sinorhizobium meliloti or Rhizobium leguminosarum

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Michael J. Mitsch ◽  
George C. diCenzo ◽  
Alison Cowie ◽  
Turlough M. Finan
Keyword(s):  
Nitrogen Fixation ◽  
Carbon Source ◽  
Sinorhizobium Meliloti ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Sequencing Analysis ◽  
Wild Type ◽  
Content Type ◽  
Transcriptional Changes ◽  
Symbiotic Properties

ABSTRACTSymbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for the generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, and malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using genetic and systems-level analyses. Expression of a malate-specific transporter (MaeP) inSinorhizobium melilotiRm1021dctmutants unable to transport C4-dicarboxylates resulted in malate import rates of up to 30% that of the wild type. This was sufficient to support SNF withMedicago sativa, with acetylene reduction rates of up to 50% those of plants inoculated with wild-typeS. meliloti.Rhizobium leguminosarumbv. viciae 3841dctmutants unable to transport C4-dicarboxylates but expressing themaePtransporter had strong symbiotic properties, withPisum sativumplants inoculated with these strains appearing similar to plants inoculated with wild-typeR. leguminosarum. This was despite malate transport rates by the mutant bacteroids being 10% those of the wild type. An RNA-sequencing analysis of the combinedP. sativum-R. leguminosarumnodule transcriptome was performed to identify systems-level adaptations in response to the inability of the bacteria to import succinate or fumarate. Few transcriptional changes, with no obvious pattern, were detected. Overall, these data illustrated that succinate and fumarate are not essential for SNF and that, at least in specific symbioses,l-malate is likely the primary C4-dicarboxylate provided to the bacterium.IMPORTANCESymbiotic nitrogen fixation (SNF) is an economically and ecologically important biological process that allows plants to grow in nitrogen-poor soils without the need to apply nitrogen-based fertilizers. Much research has been dedicated to this topic to understand this process and to eventually manipulate it for agricultural gains. The work presented in this article provides new insights into the metabolic integration of the plant and bacterial partners. It is shown that malate is the only carbon source that needs to be available to the bacterium to support SNF and that, at least in some symbioses, malate, and not other C4-dicarboxylates, is likely the primary carbon provided to the bacterium. This work extends our knowledge of the minimal metabolic capabilities the bacterium requires to successfully perform SNF and may be useful in further studies aiming to optimize this process through synthetic biology approaches. The work describes an engineering approach to investigate a metabolic process that occurs between a eukaryotic host and its prokaryotic endosymbiont.

VARIABILITY AND INTERACTION IN THE Pisum sativum L. — Rhizobium leguminosarum SYMBIOSIS

1983 ◽  
Vol 63 (3) ◽  
pp. 591-599 ◽  
Author(s):  
S. L. A. HOBBS ◽  
J. D. MAHON
Keyword(s):  
Nitrogen Fixation ◽  
Pisum Sativum ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Correlation Coefficients ◽  
Bacterial Strains ◽  
Plant Genotype ◽  
Pisum Sativum L ◽  
Performance Response ◽  
The Stability

Symbiotic nitrogen fixation was examined in 36 plant genotype-bacterial strain combinations produced by growing six genotypes of Pisum sativum L. and six strains of Rhizobium leguminosarum in all combinations. Both genotypes and strains had effects not only on nitrogen fixation but also on characters associated with plant growth and photosynthesis. However, relationships between characters differed markedly depending on whether genotype or strain means were used to calculate correlation coefficients. Genotype × strain (G × S) interactions also affected the expression of several of the characters. Using nitrogen fixation as an example, statistical methods analogous to those developed for the analysis of genotype × environment interactions were used to study this interaction. From this analysis it was apparent that the G × S variability was mainly caused by differences in the magnitude of the response of plant genotypes or bacterial strains to changes in the complementary symbiont with little difference in the stability of this response. An examination of different indicators of performance, response, and stability of that response, suggests that both plant genotypes and bacterial strains could be selected for relatively uniform fixation over a range of symbiotic partners, or that specific combinations could be selected for maximum symbiotic effectiveness.Key words: Genotype × strain, N2 fixation, photosynthesis, respiration, growth

scholarly journals Introduction of H2-Uptake Hydrogenase Genes Into Rhizobial Strains Improves Symbiotic Nitrogen Fixation in Vicia sativa and Lotus corniculatus Forage Legumes

2021 ◽  
Vol 3 ◽  
Author(s):  
Mariana Sotelo ◽  
Ana Claudia Ureta ◽  
Socorro Muñoz ◽  
Juan Sanjuán ◽  
Jorge Monza ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Lotus Corniculatus ◽  
Vicia Sativa ◽  
Uptake Hydrogenase ◽  
Forage Crops ◽  
Mesorhizobium Loti

Biological nitrogen fixation by the Rhizobium-legume symbiosis allows the conversion of atmospheric nitrogen into ammonia within root nodules mediated by the nitrogenase enzyme. Nitrogenase activity results in the evolution of hydrogen as a result of a side reaction intrinsic to the activity of this enzyme. Some rhizobia, and also other nitrogen fixers, induce a NiFe uptake hydrogenase (Hup) to recycle hydrogen produced by nitrogenase, thus improving the efficiency of the nitrogen fixation process. In this work we report the generation and symbiotic behavior of hydrogenase-positive Rhizobium leguminosarum and Mesorhizobium loti strains effective in vetch (Vicia sativa) and birsfoot trefoil (Lotus corniculatus) forage crops, respectively. The ability of hydrogen recycling was transferred to these strains through the incorporation of hup minitransposon TnHB100, thus leading to full recycling of hydrogen in nodules. Inoculation of Vicia and Lotus plants with these engineered strains led to significant increases in the levels of nitrogen incorporated into the host legumes. The level of improvement of symbiotic performance was dependent on the recipient strain and also on the legume host. These results indicate that hydrogen recycling has the potential to improve symbiotic nitrogen fixation in forage plants.

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