Acacia longifolia: A Host of Many Guests Even after Fire

Acacia longifolia is a worldwide invader that cause damage in ecosystems, expanding largely after wildfires, which promote germination of a massive seed bank. As a legume, symbiosis is determinant for adaptation. Our study aims to isolate a wider consortium of bacteria harboured in nodules, including both nitrogen and non-nitrogen fixers. Furthermore, we aim to evaluate the effects of fire in nodulation and bacterial diversity on young acacias growing in unburnt and burnt zones, one year after the fire. For this, we used molecular approaches, M13 fingerprinting and 16S rRNA partial sequencing, to identify species/genera involved and δ15N isotopic composition in leaves and plant nodules. Nitrogen isotopic analyses in leaves suggest that in unburnt zones, nitrogen fixation contributes more to plant nitrogen content. Overall, A. longifolia seems to be promiscuous and despite Bradyrhizobium spp. dominance, Paraburkholderia spp. followed by Pseudomonas spp. was also found. Several species not previously reported as nitrogen-fixers were identified, proposing other functions besides ammonia acquisition. Our study shows that bacterial communities are different in nodules after fire. Fire seems to potentiate nodulation and drives symbiosis towards nitrogen-fixers. Taken together, a multifunctional community inside nodules is pointed out which potentiate A. longifolia invasiveness and adaptation.

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A Peptidoglycan-Remodeling Enzyme Is Critical for Bacteroid Differentiation in Bradyrhizobium spp. During Legume Symbiosis

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-03-16-0052-r ◽

2016 ◽

Vol 29 (6) ◽

pp. 447-457 ◽

Cited By ~ 17

Author(s):

Djamel Gully ◽

Daniel Gargani ◽

Katia Bonaldi ◽

Cédric Grangeteau ◽

Clémence Chaintreuil ◽

...

Keyword(s):

Immune Responses ◽

Essential Role ◽

Morphological Changes ◽

Large Fraction ◽

Morphological Differentiation ◽

Capsular Polysaccharides ◽

Cell Enlargement ◽

Legume Symbiosis ◽

Bradyrhizobium Spp ◽

Peptidoglycan Layer

In response to the presence of compatible rhizobium bacteria, legumes form symbiotic organs called nodules on their roots. These nodules house nitrogen-fixing bacteroids that are a differentiated form of the rhizobium bacteria. In some legumes, the bacteroid differentiation comprises a dramatic cell enlargement, polyploidization, and other morphological changes. Here, we demonstrate that a peptidoglycan-modifying enzyme in Bradyrhizobium strains, a DD-carboxypeptidase that contains a peptidoglycan-binding SPOR domain, is essential for normal bacteroid differentiation in Aeschynomene species. The corresponding mutants formed bacteroids that are malformed and hypertrophied. However, in soybean, a plant that does not induce morphological differentiation of its symbiont, the mutation does not affect the bacteroids. Remarkably, the mutation also leads to necrosis in a large fraction of the Aeschynomene nodules, indicating that a normally formed peptidoglycan layer is essential for avoiding the induction of plant immune responses by the invading bacteria. In addition to exopolysaccharides, capsular polysaccharides, and lipopolysaccharides, whose role during symbiosis is well defined, our work demonstrates an essential role in symbiosis for yet another rhizobial envelope component, the peptidoglycan layer.

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Time of Application of Nitrogen Fertilizer to Maize at Samaru, Nigeria

Experimental Agriculture ◽

10.1017/s0014479700005573 ◽

1973 ◽

Vol 9 (2) ◽

pp. 113-120 ◽

Cited By ~ 26

Author(s):

M. J. Jones

Keyword(s):

Nitrogen Nutrition ◽

N Uptake ◽

Rainfall Distribution ◽

Total N ◽

Plant Nitrogen ◽

Yield Increase ◽

Time Of Application ◽

Nitrate N ◽

One Year

SUMMARYMaize was grown for three years at three levels of nitrogen, 56, 112 and 224 kg. N ha.−1, involving altogether nine different timing and splitting treatments. Measurements were made of grain yield, plant nitrogen status and total-N-uptake, and, in one year, movement of nitrate-N in control plot soils. Where only 56 kg. N ha.−1was applied, its time of application made very little difference to yield; at higher rates of nitrogen an unsplit application as late as seven weeks was very inefficient, but only at the highest rate did a split application give any appreciable yield increase over an unsplit application to the seed bed. Consideration of the soil nitrate-N data and the long-term pattern of rainfall distribution leads to the conclusion that leaching is unlikely to be a serious problem in the nitrogen nutrition of early-planted maize.

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Bacterial Diversity of Diabetic Foot Ulcers: Current Status and Future Prospectives

Journal of Clinical Medicine ◽

10.3390/jcm8111935 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1935 ◽

Cited By ~ 6

Author(s):

Fatemah Sadeghpour Heravi ◽

Martha Zakrzewski ◽

Karen Vickery ◽

David G. Armstrong ◽

Honghua Hu

Keyword(s):

Diabetic Foot ◽

Bacterial Communities ◽

High Sensitivity ◽

Current Status ◽

Foot Ulcers ◽

High Morbidity ◽

Diabetic Foot Ulcers ◽

Bacterial Identification ◽

Molecular Approaches ◽

The Impact

Diabetic foot ulcers (DFUs) and diabetic foot infections (DFIs) are associated with reduced patient quality of life, lower-extremity amputation, hospitalization, and high morbidity and mortality. Diverse bacterial communities have been identified in DFUs/DFIs, playing a significant role in infection prognosis. However, due to the high heterogeneity of bacterial communities colonized in DFUs/DFIs, culture-based methods may not isolate all of the bacterial population or unexpected microorganisms. Recently, high sensitivity and specificity of DNA (metagenomics) and RNA (metatranscriptomics) technologies have addressed limitations of culture-based methods and have taken a step beyond bacterial identification. As a consequence, new advances obtained from DNA- and RNA-based techniques for bacterial identification can improve therapeutic approaches. This review evaluated the current state of play in aetiology of DFUs/DFIs on culture and molecular approaches, and discussed the impact of metagenomic and metatranscriptomic methods in bacterial identification approaches.

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The challenge of remobilisation in plant nitrogen economy. A survey of physio-agronomic and molecular approaches

Annals of Applied Biology ◽

10.1111/j.1744-7348.2001.tb00086.x ◽

2001 ◽

Vol 138 (1) ◽

pp. 69-81 ◽

Cited By ~ 129

Author(s):

CELINE MASCLAUX ◽

ISABELLE QUILLERE ◽

ANDRE GALLAIS ◽

BERTRAND HIREL

Keyword(s):

Plant Nitrogen ◽

Nitrogen Economy ◽

Molecular Approaches

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Spatio-temporal dynamics of bacterial communities associated with two plant species differing in organic acid secretion: A one-year microcosm study on lupin and wheat

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2008.02.018 ◽

2008 ◽

Vol 40 (7) ◽

pp. 1772-1780 ◽

Cited By ~ 35

Author(s):

Laure Weisskopf ◽

Renée-Claire Le Bayon ◽

Florian Kohler ◽

Valérie Page ◽

Maryline Jossi ◽

...

Keyword(s):

Acid Secretion ◽

Organic Acid ◽

Plant Species ◽

Bacterial Communities ◽

Temporal Dynamics ◽

Microcosm Study ◽

Organic Acid Secretion ◽

Spatio Temporal ◽

One Year

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Effect of organic mulches on soil bacterial communities one year after application

Biology and Fertility of Soils ◽

10.1007/s00374-003-0639-9 ◽

2003 ◽

Vol 38 (5) ◽

pp. 273-281 ◽

Cited By ~ 46

Author(s):

Yoo-Jeong Yang ◽

Robert S. Dungan ◽

A. Mark Ibekwe ◽

Cesar Valenzuela-Solano ◽

David M. Crohn ◽

...

Keyword(s):

Bacterial Communities ◽

Soil Bacterial Communities ◽

Soil Bacterial ◽

One Year

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Comparison of Microbial Populations in Saliva and Feces from Healthy and Celiac Adolescents with Conventional and Molecular Approaches after Cultivation on Gluten-Containing Media: An Exploratory Study

Microorganisms ◽

10.3390/microorganisms9112375 ◽

2021 ◽

Vol 9 (11) ◽

pp. 2375

Author(s):

Tilen Senicar ◽

Andraz Kukovicic ◽

Valerija Tkalec ◽

Aleksander Mahnic ◽

Jernej Dolinsek ◽

...

Keyword(s):

Bacterial Communities ◽

Intestinal Tract ◽

Short Chain Fatty Acid ◽

Amplicon Sequencing ◽

Molecular Profiling ◽

Microbial Populations ◽

Fecal Samples ◽

Operational Taxonomic Units ◽

Molecular Approaches ◽

Partial Overlap

Microbes capable of metabolizing gluten are common in various parts of the intestinal tract. In this study, saliva and fecal samples were obtained from 10 adolescents (13–18 years of age), five of which had celiac disease (CD) and five of which were healthy volunteers (HV). Culture-enriched saliva and fecal samples were compared with molecular profiling, and microorganisms displaying lysis zones on gluten-containing media (i.e., gluten-degrading microorganisms; GDMs) were isolated. In total, 45 gluten-degrading strains were isolated, belonging to 13 genera and 15 species, including Candida albicans and Veillonella. GDMs were more common in HVs compared to CD patients and more diverse in saliva compared to feces. In saliva, GDMs showed partial overlap between HVs and CD patients. Bacterial communities in fecal samples determined with amplicon sequencing significantly differed between CD patients and HVs. Overall, 7–46 of all operational taxonomic units (OTUs) per sample were below the detection limit in the fecal samples but were present in the cultivated samples, and mainly included representatives from Lactobacillus and Enterococcus. Furthermore, differences in fecal short-chain fatty-acid concentrations between CD patients and HVs, as well as their correlations with bacterial taxa, were demonstrated.

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Diverse key nitrogen cycling genes nifH, nirS and nosZ associated with mangrove rhizosphere soils of Pichavaram as revealed by culture dependent and independent analysis.

10.21203/rs.3.rs-262569/v1 ◽

2021 ◽

Author(s):

Baskaran Viswanathan ◽

Prabavathy vaiyapuri ramalingam

Keyword(s):

Sequence Analysis ◽

Nitrogen Cycling ◽

Bacterial Communities ◽

Pcr Analysis ◽

Diversity Analysis ◽

Rhizosphere Soils ◽

Nitrogen Fixers ◽

Independent Analysis ◽

Culture Dependent ◽

Positive Controls

Abstract PCR-DGGE and culturable diversity analysis of nitrogenase gene nifH and denitrifying genes nirS and nosZ affiliated with heterotrophic and unculturable bacterial communities associated with rhizosphere of A. marina, R. mucronata, S. maritima and S. brachiata revealed the dominance of gammaproteobacterial community across the rhizospheres. Sequence analysis of the PCR-DGGE profiles of nifH genes clustered to unculturables, while majority of the nirS and nosZ genes clustered with unculturables with few culturable groups viz., Pseudomonas sp. and Halomonas sp. Culturable analysis reflected the dominance of Gammaproteobacteria as both nitrogen fixers and denitrifiers while other groups like Firmicutes and Alphaproteobacteria were very less represented among nitrogen fixers, and denitrifiers respectively. A total of 16 different genera were identified as nitrogen fixers and denitrifiers. BOX-PCR analysis of Mangovibacter, Vibrio, Bacillus and Catenococcus isolated in this study showed varied fingerprinting patterns compared to their respective positive controls reported earlier from this ecosystem, indicating they may be novel.

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Molecular Analyses of the Distribution and Function of Diazotrophic Rhizobia and Methanotrophs in the Tissues and Rhizosphere of Non-Leguminous Plants

Plants ◽

10.3390/plants8100408 ◽

2019 ◽

Vol 8 (10) ◽

pp. 408 ◽

Cited By ~ 1

Author(s):

Yoneyama ◽

Terakado-Tonooka ◽

Bao ◽

Minamisawa

Keyword(s):

N2 Fixation ◽

Active Nitrogen ◽

Leguminous Plants ◽

Molecular Analyses ◽

Nitrogen Fixers ◽

Research Perspectives ◽

Enzymatic Reduction ◽

And Function ◽

Biological Nitrogen ◽

Bradyrhizobium Spp

Biological nitrogen fixation (BNF) by plants and its bacterial associations represent an important natural system for capturing atmospheric dinitrogen (N2) and processing it into a reactive form of nitrogen through enzymatic reduction. The study of BNF in non-leguminous plants has been difficult compared to nodule-localized BNF in leguminous plants because of the diverse sites of N2 fixation in non-leguminous plants. Identification of the involved N2-fixing bacteria has also been difficult because the major nitrogen fixers were often lost during isolation attempts. The past 20 years of molecular analyses has led to the identification of N2 fixation sites and active nitrogen fixers in tissues and the rhizosphere of non-leguminous plants. Here, we examined BNF hotspots in six reported non-leguminous plants. Novel rhizobia and methanotrophs were found to be abundantly present in the free-living state at sites where carbon and energy sources were predominantly available. In the carbon-rich apoplasts of plant tissues, rhizobia such as Bradyrhizobium spp. microaerobically fix N2. In paddy rice fields, methane molecules generated under anoxia are oxidized by xylem aerenchyma-transported oxygen with the simultaneous fixation of N2 by methane-oxidizing methanotrophs. We discuss the effective functions of the rhizobia and methanotrophs in non-legumes for the acquisition of fixed nitrogen in addition to research perspectives.

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