Nitrogen-Fixing and : Two Novel Species from Plant Rhizospheres.

Two strains, M1 and H32 with nitrogen-fixing ability, were isolated from the rhizospheres of different plants. Genome sequence analysis showed that a (trogen ixation) gene cluster composed of nine genes () was conserved in the two strains. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strains M1 and H32 are members of the genus .

Correction: Co-expression of nitrogenase proteins in cotton (Gossypium hirsutum L.).

[This corrects the article DOI: 10.1371/journal.pone.

Smaller microorganisms outcompete larger ones in resistance and functional effects under disturbed agricultural ecosystems.

Body size is a key ecological trait of soil microorganisms related to their adaptation to environmental changes. In this study, we reveal that the smaller microorganisms show stronger community resistance than larger organisms in both maize and rice soil. Compared with larger organisms, smaller microorganisms have higher diversity and broader niche breadth to deploy survival strategies, because of which they are less affected by environmental selection and thus survive in complex and various kinds of environments.

Conversion of monocropping to intercropping promotes rhizosphere microbiome functionality and soil nitrogen cycling.

Intercropping can increase soil nutrient availability and provide greater crop yields for intensive agroecosystems. Despite its multiple benefits, how intercropping influences rhizosphere microbiome assemblages, functionality, and complex soil nitrogen cycling is not fully understood. Here, a three-year field experiment was carried out on different cropping system with five fertilization treatments at the main soybean production regions.

Microbial communities mediate the effect of cover cropping on soil ecosystem functions under precipitation reduction in an agroecosystem.

Cover cropping is a sustainable agricultural practice that profoundly influences soil microbial communities and ecosystem functions. However, the responses of soil ecosystem functions and microbial communities to cover cropping under the projected changes in precipitation, remain largely unexplored. To address this gap, a field experiment with cover cropping (control, hairy vetch, ryegrass, and hairy vetch plus ryegrass) and precipitation reduction (ambient precipitation and 50 % reduction in ambient precipitation) treatments was conducted from 2018 to 2020 in an agroecosystem located in the Guanzhong Plain of China.

Comparing the Potential of Silicon Nanoparticles and Conventional Silicon for Salinity Stress Alleviation in Soybean ( L.): Growth and Physiological Traits and Rhizosphere/Endophytic Bacterial Communities.

In this study, 20-day-old soybean plants were watered with 100 mL of 100 mM NaCl solution and sprayed with silica nanoparticles (SiO NPs) or potassium silicate every 3 days over 15 days, with a final dosage of 12 mg of SiO per plant. We assessed the alterations in the plant's growth and physiological traits, and the responses of bacterial microbiome within the leaf endosphere, rhizosphere, and root endosphere. The result showed that the type of silicon did not significantly impact most of the plant parameters.

Structure modification of an antibiotic: by engineering the fusaricidin bio-synthetase A in .

Fusaricidin, a lipopeptide antibiotic, is specifically produced by strains, which could strongly inhibit fungi. Fusaricidin bio-synthetase A (FusA) is composed of six modules and is essential for synthesizing the peptide moiety of fusaricidin. In this study, we confirmed the FusA of strain WLY78 involved in producing Fusaricidin LI-F07a.

Glutamine synthetase and GlnR regulate nitrogen metabolism in WLY78.

WLY78, a N-fixing bacterium, has great potential use as a biofertilizer in agriculture. Recently, we have revealed that GlnR positively and negatively regulates the transcription of the (trogen ixation) operon () in WLY78 by binding to two loci of the promoter according to nitrogen availability. However, the regulatory mechanisms of nitrogen metabolism mediated by GlnR in the genus remain unclear.

Co-expression of nitrogenase proteins in cotton (Gossypium hirsutum L.).

Chemical nitrogen fertilizer can maintain crop productivity, but overuse of chemical nitrogen fertilizers leads to economic costs and environmental pollution. One approach to reduce use of nitrogen fertilizers is to transfer nitrogenase biosynthetic pathway to non-legume plants. Fe protein encoded by nifH and MoFe protein encoded by nifD and nifK are two structural components of nitrogenase.

Assembly of nitrogenase biosynthetic pathway in by using polyprotein strategy.

Nitrogenase in some bacteria and archaea catalyzes conversion of N to ammonia. To reconstitute a nitrogenase biosynthetic pathway in a eukaryotic host is still a challenge, since synthesis of nitrogenase requires a large number of (trogen ixation) genes. Viral 2A peptide mediated "cleavage" of polyprotein is one of strategies for multigene co-expression.

Genome-wide mapping of GlnR-binding sites reveals the global regulatory role of GlnR in controlling the metabolism of nitrogen and carbon in Paenibacillus polymyxa WLY78.

Background: Paenibacillus polymyxa WLY78 is a Gram-positive, endospore-forming and N-fixing bacterium. Our previous study has demonstrated that GlnR acts as both an activator and a repressor to regulate the transcription of the nif (nitrogen fixation) operon (nifBHDKENXhesAnifV) according to nitrogen availability, which is achieved by binding to the two GlnR-binding sites located in the nif promoter region. However, further study on the GlnR-mediated global regulation in this bacterium is still needed.

Alanine synthesized by alanine dehydrogenase enables ammonium-tolerant nitrogen fixation in T27.

Most diazotrophs fix nitrogen only under nitrogen-limiting conditions, for example, in the presence of relatively low concentrations of NH (0 to 2 mM). However, T27 exhibits an unusual pattern of nitrogen regulation of nitrogen fixation, since although nitrogenase activities are high under nitrogen-limiting conditions (0 to 3 mM NH) and are repressed under conditions of nitrogen sufficiency (4 to 30 mM NH), nitrogenase activity is reestablished when very high levels of NH (30 to 300 mM) are present in the medium. To further understand this pattern of nitrogen fixation regulation, we carried out transcriptome analyses of T27 in response to increasing ammonium concentrations.

Biofertilization containing Paenibacillus triticisoli BJ-18 alters the composition and interaction of the protistan community in the wheat rhizosphere under field conditions.

Aims: Most studies focus on the effects of biofertilizer on the bacterial and fungal communities, and we still lack an understanding of biofertilizer on the protistan community. Here, the effects of biofertilizer containing Paenibacillus triticisoli BJ-18 on composition and interaction of the protistan community in the wheat rhizosphere were investigated.

Methods And Results: Biofertilizer application altered soil physicochemical properties and the protistan community composition, and significantly induced an alpha diversity decline.

sp. nov., a nitrogen-fixing species isolated from the rhizosphere soil of a peach tree.

A nitrogen-fixing, endospore-forming, motile, rod-shaped, facultative aerobic bacterium, designated 81-11, was isolated from rhizosphere soil of a peach tree collected from Handan, Hebei, PR China. From the comparison of 16S rRNA gene sequence, the strain is most closely related to DSM 27463 (96.9 %) and DSM 23593 (96.

Fusaricidin Biosynthesis Is Controlled via a KinB-Spo0A-AbrB Signal Pathway in WLY78.

Fusaricidins produced by are important lipopeptide antibiotics against fungi. The (fusaricidin biosynthesis) operon is responsible for synthesis of fusaricidins. However, the regulation mechanisms of fusaricidin biosynthesis remain to be fully clarified.

Paenibacillus sinensis sp. nov., a nitrogen-fixing species isolated from plant rhizospheres.

Two strains HN-1 and 39 were isolated from rhizospheres of different plants grown in different regions of PR China. The two strains exhibited high nitrogenase activities and possessed almost identical 16S rRNA gene sequences. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 99.

Functional analysis of multiple nifB genes of Paenibacillus strains in synthesis of Mo-, Fe- and V-nitrogenases.

Background: Biological nitrogen fixation is catalyzed by Mo-, V- and Fe-nitrogenases that are encoded by nif, vnf and anf genes, respectively. NifB is the key protein in synthesis of the cofactors of all nitrogenases. Most diazotrophic Paenibacillus strains have only one nifB gene located in a compact nif gene cluster (nifBHDKENX(orf1)hesAnifV).

Identification of Genes Involved in Fe-S Cluster Biosynthesis of Nitrogenase in WLY78.

NifS and NifU (encoded by and ) are generally dedicated to biogenesis of the nitrogenase Fe-S cluster in diazotrophs. However, and are not found in N-fixing strains, and the mechanisms involved in Fe-S cluster biosynthesis of nitrogenase is not clear. Here, we found that the genome of WLY78 contains the complete operon, a partial operon, a -like gene, two -like genes (-like and ), and two genes.

The Serine Biosynthesis of WLY78 Is Regulated by the T-Box Riboswitch.

Serine is important for nearly all microorganisms in protein and downstream amino acids synthesis, however, the effect of serine on growth and nitrogen fixation was not completely clear in many bacteria, besides, the regulatory mode of serine remains to be fully established. In this study, we demonstrated that L-serine is essential for growth and nitrogen fixation of WLY78, but high concentrations of L-serine inhibit growth, nitrogenase activity, and expression. Then, we revealed that expression of the whose gene product catalyzes the first reaction in the serine biosynthetic pathway is regulated by the T-box riboswitch regulatory system.

Synthesis of nitrogenase by Paenibacillus sabinae T27 in presence of high levels of ammonia during anaerobic fermentation.

Biological nitrogen fixation is usually inhibited by fixed nitrogen. Paenibacillus sabinae T27, a Gram-positive, spore-forming diazotroph, possesses high nitrogenase activity and has 3 copies of nifH (nifH, nifH2, nifH3), a copy of nifDK, and multiple nifHDK-like genes. In this study, we found that P.

Effects of an EPS Biosynthesis Gene Cluster of WLY78 on Biofilm Formation and Nitrogen Fixation under Aerobic Conditions.

Exopolysaccharides (EPS) are of high significance in bacterial biofilm formation. However, the effects of EPS cluster(s) on biofilm formation in species are little known. In this study, we have shown that WLY78, a N-fixing bacterium, can form biofilm.

Diazotroph BJ-18 Drives the Variation in Bacterial, Diazotrophic and Fungal Communities in the Rhizosphere and Root/Shoot Endosphere of Maize.

Application of diazotrophs (N-fixing microorganisms) can decrease the overuse of nitrogen (N) fertilizer. Until now, there are few studies on the effects of diazotroph application on microbial communities of major crops. In this study, the diazotrophic and endospore-forming BJ-18 was inoculated into maize soils containing different N levels.

Differentially expressed circular RNAs in a murine asthma model.

Allergic asthma is one of the most common allergic diseases; however, the mechanisms underlying its development have yet to be fully elucidated. Although allergic diseases are inheritable, genetic variance alone cannot explain the notable increase in the prevalence of allergic diseases over a short period of time in recent decades. Recently, research focus has been shifting to epigenetic factors, such as non‑coding RNAs.

Siderophore and indolic acid production by BJ-18 and their plant growth-promoting and antimicrobe abilities.

BJ-18, a N-fixing bacterium, is able to promote plant growth, but the secondary metabolites that may play a role in promoting plant growth have never been characterized. In this study, untargeted metabolomics profiling of . BJ-18 indicated the existence of 101 known compounds, including N-acetyl ornithine, which is the precursor of siderophores, plant growth regulators such as trehalose 6-phosphate, betaine and trigonelline, and other bioactive molecules such as oxymatrine, diosmetin, luotonin A, (-)-caryophyllene oxide and tetrahydrocurcumin.

Phosphate solubilizing bacteria stimulate wheat rhizosphere and endosphere biological nitrogen fixation by improving phosphorus content.

Phosphate (P) availability often limits biological nitrogen fixation (BNF) by diazotrophic bacteria. In soil, only 0.1% of the total P is available for plant uptake.