Coproporphyria excretion by Rhizobium meliloti

1969 ◽  
Vol 15 (2) ◽  
pp. 242-244 ◽  
Author(s):  
G. S. Hendry ◽  
D. C. Jordan
Keyword(s):  
Host Plant ◽  
Growth Medium ◽  
Rhizobium Meliloti ◽  
Root Nodules ◽  
Nitrogen Fixing ◽  
Active Nitrogen ◽  
Leguminous Host

Strains of Rhizobium meliloti were found to excrete coproporphyrin into the growth medium. Maximum excretion in a modified Dudman's medium containing arginine occurred at a shaker speed of at least 98 oscillations/min (2 in. travel) and at Fe3+ and biotin concentrations of 1 μg/ml and 1 μg/l respectively. No consistent differences in coproporphyrin excretion were noted among strains differing in their ability to form active, nitrogen-fixing root nodules on their leguminous host plant.

scholarly journals FrankiaDiversity in Host Plant Root Nodules Is Independent of Abundance or Relative Diversity ofFrankiaPopulations in Corresponding Rhizosphere Soils

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Seifeddine Ben Tekaya ◽  
Trina Guerra ◽  
David Rodriguez ◽  
Jeffrey O. Dawson ◽  
Dittmar Hahn
Keyword(s):  
Host Plant ◽  
Root Nodule ◽  
Root Nodules ◽  
Actinorhizal Plants ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Content Type ◽  
Rhizosphere Soils ◽  
Root Nodule Formation ◽  
Host Infection

ABSTRACTActinorhizal plants form nitrogen-fixing root nodules in symbiosis with soil-dwelling actinobacteria within the genusFrankia, and specificFrankiataxonomic clusters nodulate plants in corresponding host infection groups. In same-soil microcosms, we observed that some host species were nodulated (Alnus glutinosa,Alnus cordata,Shepherdia argentea,Casuarina equisetifolia) while others were not (Alnus viridis,Hippophaë rhamnoides). Nodule populations were represented by eight different sequences ofnifHgene fragments. Two of these sequences characterized frankiae inS. argenteanodules, and three others characterized frankiae inA. glutinosanodules. Frankiae inA. cordatanodules were represented by five sequences, one of which was also found in nodules fromA. glutinosaandC. equisetifolia, while another was detected in nodules fromA. glutinosa. Quantitative PCR assays showed that vegetation generally increased the abundance of frankiae in soil, independently of the target gene (i.e.,nifHor the 23S rRNA gene). Targeted Illumina sequencing ofFrankia-specificnifHgene fragments detected 24 unique sequences from rhizosphere soils, 4 of which were also found in nodules, while the remaining 4 sequences in nodules were not found in soils. Seven of the 24 sequences from soils represented >90% of the reads obtained in most samples; the 2 most abundant sequences from soils were not found in root nodules, and only 2 of the sequences from soils were detected in nodules. These results demonstrate large differences between detectableFrankiapopulations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specificFrankiapopulations in soils.IMPORTANCEThe nitrogen-fixing actinobacteriumFrankiaforms root nodules on actinorhizal plants, with members of specificFrankiataxonomic clusters nodulating plants in corresponding host infection groups. We assessedFrankiadiversity in root nodules of different host plant species, and we related specific populations to the abundance and relative distribution of indigenous frankiae in rhizosphere soils. Large differences were observed between detectableFrankiapopulations in soil and those in root nodules, suggesting that root nodule formation is not a function of the abundance or relative diversity of specificFrankiapopulations in soils but rather results from plants potentially selecting frankiae from the soil for root nodule formation. These data also highlight the necessity of using a combination of different assessment tools so as to adequately address methodological constraints that could produce contradictory data sets.

scholarly journals Determinants of Host Range Specificity in Legume-Rhizobia Symbiosis

2020 ◽  
Vol 11 ◽  
Author(s):  
Liam Walker ◽  
Beatriz Lagunas ◽  
Miriam L. Gifford
Keyword(s):  
Host Range ◽  
Host Plant ◽  
Molecular Mechanisms ◽  
High Efficiency ◽  
Current Knowledge ◽  
Root Nodules ◽  
Partner Choice ◽  
Nodule Development ◽  
Symbiotic Association ◽  
Nitrogen Fixing

Leguminous plants possess the almost unique ability to enter symbiosis with soil-resident, nitrogen fixing bacteria called rhizobia. During this symbiosis, the bacteria physically colonize specialized organs on the roots of the host plant called nodules, where they reduce atmospheric nitrogen into forms that can be assimilated by the host plant and receive photosynthates in return. In order for nodule development to occur, there is extensive chemical cross-talk between both parties during the formative stages of the symbiosis. The vast majority of the legume family are capable of forming root nodules and typically rhizobia are only able to fix nitrogen within the context of this symbiotic association. However, many legume species only enter productive symbiosis with a few, or even single rhizobial species or strains, and vice-versa. Permitting symbiosis with only rhizobial strains that will be able to fix nitrogen with high efficiency is a crucial strategy for the host plant to prevent cheating by rhizobia. This selectivity is enforced at all stages of the symbiosis, with partner choice beginning during the initial communication between the plant and rhizobia. However, it can also be influenced even once nitrogen-fixing nodules have developed on the root. This review sets out current knowledge about the molecular mechanisms employed by both parties to influence host range during legume-rhizobia symbiosis.

scholarly journals Draft Genome Sequence of the Nitrogen-Fixing and Hormogonia-Inducing CyanobacteriumNostoc cycadaeStrain WK-1, Isolated from the Coralloid Roots ofCycas revoluta

2018 ◽  
Vol 6 (7) ◽  
Author(s):  
Yu Kanesaki ◽  
Masaki Hirose ◽  
Yuu Hirose ◽  
Takatomo Fujisawa ◽  
Yasukazu Nakamura ◽  
...  
Keyword(s):  
Host Plant ◽  
Genome Sequence ◽  
Draft Genome ◽  
Draft Genome Sequence ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Nitrogen Fixing ◽  
Coralloid Roots ◽  
Cycas Revoluta

ABSTRACTWe report here the whole-genome sequence ofNostoc cycadaestrain WK-1, which was isolated from cyanobacterial colonies growing in the coralloid roots of the gymnospermCycas revoluta. It can provide valuable resources to study the mutualistic relationships and the syntrophic metabolisms between the cyanobacterial symbiont and the host plant,C. revoluta.

Induction of Pre-Infection Thread Structures in the Leguminous Host Plant by Mitogenic Lipo-Oligosaccharides of Rhizobium

Science ◽  
1992 ◽  
Vol 257 (5066) ◽  
pp. 70-72 ◽  
Author(s):  
A. A. N. van Brussel ◽  
R. Bakhuizen ◽  
P. C. van Spronsen ◽  
H. P. Spaink ◽  
T. Tak ◽  
...  
Keyword(s):  
Host Plant ◽  
Infection Thread ◽  
Leguminous Host

scholarly journals Development of the nitrogen-fixing and protein-synthesizing apparatus of bacteroids in pea root nodules

1979 ◽  
Vol 562 (3) ◽  
pp. 515-526 ◽  
Author(s):  
T. Bisseling ◽  
R.C. Van Den Bos ◽  
M.W. Weststrate ◽  
M.J.J. Hakkaart ◽  
A. Van Kammen
Keyword(s):  
Root Nodules ◽  
Nitrogen Fixing ◽  
Pea Root
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