Nitrogen Fixation by Pulse Crops and the Use of Nitrogen Isotopic Techniques to Measure the Fixation Capacity

2018 ◽  
pp. 21-38
Author(s):  
Minh-Long Nguyen
Keyword(s):  
Nitrogen Fixation ◽  
Pulse Crops ◽  
Fixation Capacity

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2

2021 ◽  
Author(s):  
Yunfa Qiao ◽  
Shujie Miao ◽  
Jian Jin ◽  
Ulrike Mathesius ◽  
Caixian Tang
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
Medicago Truncatula ◽  
N2 Fixation ◽  
Sink Strength ◽  
Wild Type ◽  
Total N ◽  
Autoregulation Of Nodulation ◽  
Nodulation Mutants ◽  
Fixation Capacity

Abstract Background and Aims Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. ‘Autoregulation of nodulation’ mutants super-nodulate and are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. Methods We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 μmol mol -1). Nodule formation and N2 fixation were assessed in soil-grown plants at 18 and 42 days after sowing. Key results Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed-N per plant of all genotypes increased with increasing CO2 concentration and reached the maximum around 700 μmol mol -1. While the sunn-4 mutant showed strong growth-retardation compared to wild-type plants, elevated CO2 increased shoot biomass and total N content of rdn1-1 mutant up to two-fold. This was accompanied by a four-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. Conclusions These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 on plant growth and N2 fixation.

scholarly journals Improvement in nitrogen fixation capacity could be part of the domestication process in soybean

Heredity ◽  
2016 ◽  
Vol 117 (2) ◽  
pp. 84-93 ◽  
Author(s):  
N Muñoz ◽  
X Qi ◽  
M-W Li ◽  
M Xie ◽  
Y Gao ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Fixation Capacity ◽  
Domestication Process

Phoma medicaginis colonizes Medicago truncatula root nodules and affects nitrogen fixation capacity

2014 ◽  
Vol 141 (2) ◽  
pp. 375-383 ◽  
Author(s):  
Saif-Allah Chihaoui ◽  
Naceur Djébali ◽  
Moncef Mrabet ◽  
Fathi Barhoumi ◽  
Ridha Mhamdi ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Truncatula ◽  
Root Nodules ◽  
Phoma Medicaginis ◽  
Fixation Capacity

scholarly journals Biological nitrogen fixation by pulse crops on the semiarid Canadian Prairie

2016 ◽  
Author(s):  
Zakir Hossain ◽  
Xiaoyu Wang ◽  
Chantal Hamel ◽  
J. Diane Knight ◽  
Malcolm John Morrison ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Canadian Prairie ◽  
Pulse Crops ◽  
Biological Nitrogen

Evaluation of Biological Nitrogen Fixation Capacity in Arachis Species and the Possible Role of Polyploidy1

1994 ◽  
Vol 21 (1) ◽  
pp. 55-60 ◽  
Author(s):  
H. T. Stalker ◽  
M. L. Nickum ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis
Keyword(s):  
Nitrogen Fixation ◽  
Arachis Hypogaea ◽  
Cover Crops ◽  
Biological Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Diploid Species ◽  
Dry Matter Accumulation ◽  
Arachis Species ◽  
Fixation Capacity ◽  
Biological Nitrogen

Abstract Arachis species have potential for enhancing cultivated peanut (Arachis hypogaea L.) germplasm as forages and cover crops. This study's objective was to evaluate a range of Arachis species for biological nitrogen fixation capacity. Several Arachis species are tetraploids, and it has been shown that tetraploidy may play an important role in nodule initiation. Species were first tested under natural field conditions and then in the greenhouse using three Bradyrhizobium strains that had been previously shown to be effective on peanut. Nodule number, nodule weight, nitrogenase activity determined by acetylene reduction, and shoot dry weight were measured as indicators of nitrogen fixation capacity. In the field, tetraploid species produced significantly more nodules than the diploids, but total dry matter accumulation was independent of the number of nodules or rate of fixation. In the greenhouse, no significant differences were observed among the bradyrhizobial strains. Arachis hypogaea and A. monticola showed significantly higher measures of nitrogen fixation capacity for all measured traits than the diploid species. However, autotetraploid plants of A. villosa did not have significantly more nodules than diploids of the same accession; the autotetraploids consistently had higher nitrogenase activity. Arachis pusilla never formed a symbiotic relationship with the bradyrhizobial strains used.

Characterisation of dry and mucoid colonies isolated from Australian rhizobial inoculant strains for Medicago species

2005 ◽  
Vol 45 (3) ◽  
pp. 151 ◽  
Author(s):  
A. McInnes ◽  
P. Holford ◽  
J. E. Thies
Keyword(s):  
Nitrogen Fixation ◽  
Sinorhizobium Meliloti ◽  
Dry Weight ◽  
Sequence Element ◽  
Shoot Dry Weight ◽  
Single Colony ◽  
Agar Media ◽  
Fixation Capacity ◽  
Medicago Species ◽  
K Antigen

The presence of dry and mucoid colonies in cultures of rhizobial strains used in the production of commercial Australian inoculants is of concern for quality assurance because of the possibility of altered capacity for nodulation and nitrogen fixation by the different colony types. In this study, single colony isolates obtained from dry and mucoid colonies present in commercial cultures of Sinorhizobium meliloti were investigated to identify stability in culture, genetic identity and changes in exopolysaccharide (EPS) production, nodulation and nitrogen fixation. The 2 strains studied were WSM688 and WSM826 (Australian inoculant strains for annual and perennial medics, respectively), both of which produced only mucoid colonies on agar media when originally isolated from nodules. Dry and mucoid single colony isolates from the ‘mother cultures’ of the 2 strains exhibited stable colony phenotypes during successive subculturing in our laboratory and were shown to be most closely related to S. meliloti using 16S rRNA partial sequencing. All isolates produced at least 1 of 3 exopolysaccharides (succinoglycan, EPS II and K antigen) that are required for successful nodulation of Medicago species by S. meliloti strains, as indicated by nodulation of host legumes. Strain WSM826 isolates probably produce succinoglycan, as shown by similarity to the succinoglycan-producing strain Rm1021 in a calcofluor binding assay. In contrast to published work, there was no evidence that loss of mucoidy in dry colony isolates of either strain was associated with the presence of an insertion sequence element in the expR gene that inhibits EPS II production. For strain WSM688, dry and mucoid isolates were identical by PCR fingerprinting and showed a similar capacity to nodulate and fix nitrogen with the target host legume M. truncatula in glasshouse tests. In contrast, strain WSM826 mucoid isolates produced PCR fingerprints that were different from each other and from the WSM826 dry colony isolates. Dry and mucoid colonies may have arisen from substantial genetic change or through contamination of cultures by other S. meliloti strains. One WSM826 mucoid isolate (826-3) produced significantly lower shoot dry weight when inoculated onto both the target host M. sativa and non-target host M. truncatula, even though the capacity to nodulate both hosts was retained. This suggests that this isolate was affected in its nitrogen fixation capacity. Further research is required to identify the origin and extent of colony variation in commercial S. meliloti cultures.

Symbiogenetics and breeding of a macrosymbiont for increased nitrogen fixation capacity with special reference to the pea (Pisum sativum L.)

2011 ◽  
Vol 1 (1) ◽  
pp. 73-87 ◽  
Author(s):  
K. K. Sidorova ◽  
V. K. Shumny ◽  
E. Yu. Vlasova ◽  
M. N. Glyanenko ◽  
T. M. Mishchenko ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Pisum Sativum ◽  
Special Reference ◽  
Pisum Sativum L ◽  
Fixation Capacity
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