scholarly journals Divulging diazotrophic bacterial community structure in Kuwait desert ecosystems and their N2-fixation potential

2019 ◽  
Author(s):  
M. K. Suleiman ◽  
A. M. Quoreshi ◽  
N. R. Bhat ◽  
A. J. Manuvel ◽  
M. T. Sivadasan
Keyword(s):  
Plant Species ◽  
Root Nodules ◽  
Rrna Gene ◽  
Limited Information ◽  
Native Plant ◽  
Rhizospheric Soil ◽  
Nitrogen Fixing ◽  
Free Living ◽  
Nitrogen Fixers ◽  
Haloxylon Salicornicum

AbstractKuwait is a semi-arid region with harsh climatic conditions with poor available soil nutrient essential for the growth of plants. Kuwait’s ecosystem is relatively N-poor ecosystem when compared to the other ecosystems. Biological nitrogen fixation (BNF) is a spontaneous process in which diazotrophic bacteria fixes the atmospheric nitrogen directly in to the bionetwork. At present, there is limited information on free-living and root associated nitrogen-fixing bacteria, their potential to fix nitrogen to aid natural plant communities in the desert of Kuwait. In this study, free-living N2-fixing bacteria were enriched and isolated from the rhizospheric soil of three keystone native plant species of Kuwait; such as Rhanterium epapposum, Farsetia aegyptia, and Haloxylon salicornicum. Root associated bacteria were directly isolated from the root nodules of Vachellia pachyceras. In this study, a number of free-living and root associated dizotrophs were isolated from various rhizospheric soils of three native shrubs and root nodules from one tree species. The screened isolates were assessed for nitrogen-fixing ability and identified using Acetylene Reduction Assay (ARA) and 16s rRNA gene sequencing, respectively. Our study successfully identified all the 50 nitrogen-fixers isolated initially and out of that, 78% were confirmed as nitrogen-fixers using ARA. Among the identified nitrogen fixers, the genus Rhizobium is dominant in rhizospheric soil of Rhanterium epapposum, whereas Pseudomonas and Rhizobium are dominant in the rhizospheric soil of Farsetia aegyptia, and Haloxylon salicornicum respectively. The species Agrobacterium tumefaciens is found dominant in the root nodules of V. pachyceras. The current results indicate that plant species and their rhizospheric effects are important drivers for specificity of microbial diversity in arid soils. To our knowledge, this study is the first investigation of culture-based isolation, molecular identification, and evaluation of N2-fixing ability of diazotrophs from Kuwait desert environment.

NON-SYMBIOTIC NITROGEN FIXATION IN SOME QUEBEC SOILS

1965 ◽  
Vol 11 (1) ◽  
pp. 29-38 ◽  
Author(s):  
P-C. Chang ◽  
R. Knowles
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Soil Types ◽  
Anaerobic Incubation ◽  
Nitrogen Fixing ◽  
Free Living ◽  
Aerobic Conditions ◽  
Bacterial Counts ◽  
Facultatively Anaerobic ◽  
Nitrogen Fixers

The occurrence of free-living nitrogen fixers, the potential for nitrogen fixation, and the correlation between the nitrogen-fixing capacities of the soils and bacterial counts were studied using representative Quebec soils.Clostridium occurred more frequently than did Azotobacter. Studies with N15showed that nitrogen fixation was more frequent under anaerobic than under aerobic conditions in all the soil types studied in their unamended state. The addition of glucose stimulated nitrogen fixation. During anaerobic incubation, nitrogen fixation was found to be correlated significantly with the increase in numbers of both total aerobes and Clostridia. The results suggested that facultatively anaerobic nitrogen fixers, and aerobic nitrogen fixers other than Azotobacter, were present.

scholarly journals Methylobacterium nodulans sp. nov., for a group of aerobic, facultatively methylotrophic, legume root-nodule-forming and nitrogen-fixing bacteria

2004 ◽  
Vol 54 (6) ◽  
pp. 2269-2273 ◽  
Author(s):  
Philippe Jourand ◽  
Eric Giraud ◽  
Gilles Béna ◽  
Abdoulaye Sy ◽  
Anne Willems ◽  
...  
Keyword(s):  
Carbon Source ◽  
16S Rrna ◽  
Root Nodule ◽  
Root Nodules ◽  
Phenotypic Characterization ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Protein Patterns ◽  
Gene Encoding

Data on 72 non-pigmented bacterial strains that specifically induce nitrogen-fixing root nodules on the legume species Crotalaria glaucoides, Crotalaria perrottetii and Crotalaria podocarpa are reviewed. By SDS-PAGE analysis of total protein patterns and by 16S rRNA PCR-RFLP, these strains form a homogeneous group that is separate from other legume root-nodule-forming bacteria. The 16S rRNA gene-based phylogeny indicates that these bacteria belong to the genus Methylobacterium. They can grow on C1 compounds such as methanol, formate and formaldehyde but not methylamine as sole carbon source, and carry an mxaF gene, encoding methanol dehydrogenase, which supports their methylotrophic metabolism. Presence of a nodA nodulation gene, and ability to nodulate plants of Crotalaria species and to fix nitrogen are features that separate the strains currently included in this group from other members of the genus Methylobacterium. The present study includes additional genotypic and phenotypic characterization of this novel Methylobacterium species, i.e. nifH gene sequence, morphology, physiology, enzymic and carbon source assimilation tests and antibiotic resistance. The name Methylobacterium nodulans sp. nov. (type strain, ORS 2060T=CNCM I 2342T=LMG 21967T) is proposed for this group of root-nodule-forming bacteria.

scholarly journals Rhizobium-Linked Nutritional and Phytochemical Changes Under Multitrophic Functional Contexts in Sustainable Food Systems

2021 ◽  
Vol 4 ◽  
Author(s):  
Dennis M. W. Ochieno ◽  
Edwin M. Karoney ◽  
Edward K. Muge ◽  
Evans N. Nyaboga ◽  
Danstone L. Baraza ◽  
...  
Keyword(s):  
Plant Species ◽  
Food Systems ◽  
Host Plants ◽  
Root Nodules ◽  
Trophic Levels ◽  
Free Living ◽  
Sustainable Food Systems ◽  
Sustainable Food ◽  
Beneficial Effects ◽  
Leguminous Host

Rhizobia are bacteria that exhibit both endophytic and free-living lifestyles. Endophytic rhizobial strains are widely known to infect leguminous host plants, while some do infect non-legumes. Infection of leguminous roots often results in the formation of root nodules. Associations between rhizobia and host plants may result in beneficial or non-beneficial effects. Such effects are linked to various biochemical changes that have far-reaching implications on relationships between host plants and the dependent multitrophic biodiversity. This paper explores relationships that exist between rhizobia and various plant species. Emphasis is on nutritional and phytochemical changes that occur in rhizobial host plants, and how such changes affect diverse consumers at different trophic levels. The purpose of this paper is to bring into context various aspects of such interactions that could improve knowledge on the application of rhizobia in different fields. The relevance of rhizobia in sustainable food systems is addressed in context.

scholarly journals From roots to leaves: the capacity of Micromonospora to colonize different legume tissues

2021 ◽  
Author(s):  
Patricia Benito ◽  
Lorena Carro ◽  
Rodrigo Bacigalupe ◽  
Maite Ortuzar ◽  
Martha E. Trujillo
Keyword(s):  
16S Rrna ◽  
Pisum Sativum ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Root Nodules ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Rrna Gene Sequence ◽  
Plant Model ◽  
Plant Polymer

An important number of Micromonospora strains have been reported from nitrogen fixing root nodules of legume and actinorhizal plants. However, the question of whether this bacterium can also be found in other parts of these plants remains unanswered. Over 150 strains were recovered from different Lupinus angustifolius and Pisum sativum tissues including leaves, stems, roots, and nodules. Ninety-seven percent of the isolates were identified by 16S rRNA gene sequence in the target genus and were associated with 27 different Micromonospora species. Plant-polymer degrading enzymes are suspected to play a role in the colonization of plants. To this end, bacterial enzymatic activity assays for amylases, cellulases, chitinases, pectinases and xylanases were determined. All strains produced xylanases and pectinases, while 98.6%, 98%, and 94.6% of them produced amylases, cellulases, and chitinases, respectively. The most productive strains included seven isolates from P. sativum and one from L. angustifolius. Strain Micromonospora lupini ML01-gfp was used to determine its capacity to reach and colonize different plant organs using P. sativum as the plant model. Stem and leaf samples were monitored by optical and fluorescence microscopy to locate the tagged strain. These results strongly suggest that Micromonospora is able, not only to infect nitrogen-fixing nodules, but also of reaching other parts of the host plant, especially the leaves.

Diversity of Indigenous Symbiotic Nitrogen Fixing Bacteria from Blackgram [Vigna mungo (L.) Hepper] Cultivated in Rice Fallows

2020 ◽  
Author(s):  
T. Satyanandam ◽  
K. Babu ◽  
B. Yellamanda ◽  
K. Vijaya Kumar ◽  
G. Rosaiah ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Root Nodules ◽  
Pcr Amplification ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
High Genetic Diversity ◽  
Microbiological Methods

Background: Legume nodulating bacteria (LNB), also known as rhizobia produce root nodules on leguminous plants where in nitrogen fixation takes place. In agriculture, this symbiotic relationship is significant as it provides nitrogenous fertilizers to the leguminous crops. Traditionally rhizobia were exclusively members of the Rhizobiaceae family in the Alphaproteobacteria class of bacteria. Several reports revealed that large number of diazotrophs have the ability to nodulate and fix atmospheric N2 in legumes in addition to rhizobia which are outside the Alphaproteobacteria class. Relatively less information is available on the genetic diversity of indigenous rhizobia nodulating blackgram cultivated in rice fallows. Hence the present study was carried out to know the diversity of symbiotic native nitrogen fixing bacteria isolated from the root nodules of blackgram grown in rice fallows using partial 16S rRNA sequencing.Methods: Nitrogen fixing microsymbionts (Rhizobium strains) from root nodules of blackgram were isolated on yeast extract mannitol agar (YEMA) medium. The pure cultures were maintained at 28±2°C for 48 h. Identification of Rhizobium isolates was done by using various tests and Morphological characterization of isolates was also done by using standard microbiological methods. The PCR amplification and sequencing of 16S rRNA gene of isolates were carried out to identify the isolates.Result: In the present study four strains of Rhizobium designated as VM-2, VM-8, VM-9 and VM-15 were isolated. Morphologically colonies of all strains are round, transparent, entire, convex and smooth. They are Gram-ve and rod shaped. Mucilage production is noticed in VM-2, VM-8 and VM-9. The 16S rRNA gene sequences revealed that the strain VM-2 showed a close relation with Rhizobium, VM-8 and VM-9 with Bradyrhizobium where as VM-15 with Achromobater. It was concluded that the symbiotic nitrogen fixing bacteria isolated from the root nodules of blackgram cultivated in rice fallows exhibited high genetic diversity. 

scholarly journals Biochemical and Molecular Phylogenetic Study of Agriculturally Useful Association of a Nitrogen-Fixing Cyanobacterium and NoduleSinorhizobiumwithMedicago sativaL.

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
E. V. Karaushu ◽  
I. V. Lazebnaya ◽  
T. R. Kravzova ◽  
N. A. Vorobey ◽  
O. E. Lazebny ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Bacterial Consortium ◽  
Biochemical Properties ◽  
Nostoc Muscorum ◽  
Phylogenetic Study ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Molecular Phylogenetic Study ◽  
Molecular Phylogenetic

Seed inoculation with bacterial consortium was found to increase legume yield, providing a higher growth than the standard nitrogen treatment methods. Alfalfa plants were inoculated by mono- and binary compositions of nitrogen-fixing microorganisms. Their physiological and biochemical properties were estimated. Inoculation by microbial consortium ofSinorhizobium melilotiT17 together with a new cyanobacterial isolateNostocPTV was more efficient than the single-rhizobium strain inoculation. This treatment provides an intensification of the processes of biological nitrogen fixation by rhizobia bacteria in the root nodules and an intensification of plant photosynthesis. Inoculation by bacterial consortium stimulates growth of plant mass and rhizogenesis and leads to increased productivity of alfalfa and to improving the amino acid composition of plant leaves. The full nucleotide sequence of the rRNA gene cluster and partial sequence of the dinitrogenase reductase (nifH) gene ofNostocPTV were deposited to GenBank (JQ259185.1, JQ259186.1). Comparison of these gene sequences ofNostocPTV with all sequences present at the GenBank shows that this cyanobacterial strain does not have 100% identity with any organisms investigated previously. Phylogenetic analysis showed that this cyanobacterium clustered with high credibility values withNostoc muscorum.

scholarly journals Rhizobial microsymbionts of the narrowly endemic Oxytropis species growing in Kamchatka possess a set of genes that are associated with T3SS and T6SS secretion systems and can affect the development of symbiosis

2020 ◽  
Author(s):  
P. Guro ◽  
V. Safronova ◽  
A. Sazanova ◽  
I. Kuznetsova ◽  
A. Belimov ◽  
...  
Keyword(s):  
Host Specificity ◽  
Root Nodules ◽  
Kamchatka Peninsula ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Symbiotic Genes ◽  
Secretion Systems ◽  
Legume Symbiosis ◽  
Microbe Interactions ◽  
Different Strains

A collection of rhizobial strains isolated from root nodules of the narrowly endemic legume species Oxytropis erecta, O. anadyrensis, O. kamtschatica and O. pumilio growing on the Kamchatka Peninsula (Russian Federation) was obtained. Analysis of the 16S rRNA gene sequence showed a significant diversity of isolates belonging to the families Rhizobiaceae (Rhizobium), Phyllobacteriaceae (Mesorhizobium, Phyllobacterium) and Bradyrhizobiaceae (Bosea, Tardiphaga). Pairs of taxonomically different strains in various combinations were isolated from some nodules of Oxytropis plants. Plant nodulation assays showed that only strains belonging to the genus Mesorhizobium (M. jarvisii, M. loti and M. huakuii) could form nitrogen-fixing nodules. The nitrogen-fixing activity of the strains was more associated with the host plant than with the species of strains. The whole genome sequences analysis showed that the strains M. loti 582 and M. huakuii 583 possessed symbiotic genes necessary for the formation of effective symbiosis and grouped into Sym-clusters. In contrast, the strain T. robiniae 581 had only a reduced number of fix genes, while the strains Phyllobacterium sp. 628 and R. lusitanum 629 possesed only individual symbiotic genes, which obviously did not participate in the formation of nodules. It was also stated that the strains M. loti 582 and M. huakuii 583 had a significantly larger set of genes related to the secretion systems T3SS and T6SS that can affect the host specificity of strains, compared with 6 commercial strains used as reference. These two strains formed nodules of two types (typical elongated and atypical rounded) on Oxytropis plants. We suggest that a possible cause of the observed phenomenon is the availability of different nodulation strategies in these strains (dependent and independent of Nod-factors). Thus, as a result of studying the collection of strains isolated from the narrow endemic species of Kamchatka Oxytropis, interesting objects were selected to study the functions of the T3SS and T6SS genes, and their role in the development of rhizobia-legume symbiosis. The prospects of using strains with gene systems for both symbiotic and non-symbiotic nodulation to enhance the efficiency of plant-microbe interactions by expanding the host specificity and increasing the efficiency of nodulation are discussed.

Native plant species field evaluation in salt desert: good materials, bad situation

2015 ◽  
Vol 16 (2) ◽  
pp. 87-95 ◽  
Author(s):  
N. Grant-Hoffman ◽  
S. Parr ◽  
T. Blanke
Keyword(s):  
Plant Species ◽  
Field Evaluation ◽  
Native Plant ◽  
Native Plant Species ◽  
Salt Desert

Ten-year persistence of native plant species on a green roof in Northeast US

2017 ◽  
Vol 18 (3) ◽  
pp. 227-234
Author(s):  
Jessica D Lubell ◽  
Bryan Connolly ◽  
Kristina N Jones
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Native Plant ◽  
Native Plant Species ◽  
Northeast Us
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