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The soybean rhizosphere has a specific microbial community, but the differences in microbial community structure between different soybean genotypes have not been explained. The present study analyzed the structure of the rhizosphere microbial community in three soybean genotypes. Differences in rhizosphere microbial communities between different soybean genotypes were verified using diversity testing and community composition, and each genotype had a specific rhizosphere microbial community composition. Co-occurrence network analysis found that different genotype plant hosts had different rhizosphere microbial networks. The relationship between rhizobia and rhizosphere microorganisms in the network also exhibited significant differences between different genotype plant hosts. The ecological function prediction found that different genotypes of soybean recruited the specific rhizosphere microbial community. These results demonstrated that soybean genotype regulated rhizosphere microbial community structure differences. The study provides a reference and theoretical support for developing soybean microbial inoculum in the future.

ABSTRACT: Objectives: Here, we report the complete genome of strain WB, isolated from the rhizosphere of a healthy watermelon from a Fusarium wilt diseased field, which possesses antifungal activity against Fusarium oxysporum f. sp. niveum (Fon) and reduces the incidence of Fusarium wilt in watermelon. Methods: Genome sequences were determined using the Illumina HiSeq and PacBio platforms. Genome assembly was performed by Unicycler software. Gene clusters responsible for secondary metabolite biosynthesis were predicted using antiSMASH. Results: The size of the genome was 3 896 799 base pairs, and there were 3977 coding DNA sequences (CDSs). The G+C content of the circular genome was 46.65%, and there were 27 rRNAs and 86 tRNAs. Strain WB was finally designated Bacillus velezensis based on phylogenomic analyses. In addition, 13 gene clusters were related to the synthesis of antimicrobial secondary metabolites, including surfactin, fengycin, iturin, bacillibactin, bacilysin, bacillaene, and butirosin. Conclusion: The complete genome sequence of strain WB reported here will be a valuable reference for studying the biocontrol mechanisms of Fusarium wilt in watermelon.

Objective To evaluate the potential biological functions of non-viral neutralizing antibodies associated with linear epitopes of the SARS-CoV-2 spike protein. Methods The linear epitope S2-78 with the highest response frequency and longest antibody retention time in COVID-19 patients was selected according to previous reports. After immunizing mice with keyhole limpet hemocyain conjugated S2-78 polypeptide(KLH-S2-78), the serum anti-S2-78 IgG antibody level, mouse behavioral phenotype and the density of microglia in the brain were detected. Results KLH-S2-78 immunized mice developed high titers of anti-S2-78 IgG antibodies(the highest titer was 25 600, A450=0.305 5), a psychomotor-like behavioral phenotype with defective sensorimotor gating, impaired olfactory function, and impaired spontaneity. The density of microglia significantly increased in the cortex and hippocampus(P＜0 .05), suggesting a state of central inflammatory stress. Conclusions Anti-S2-78 IgG antibody may cause neuroinflammatory damages in the brain tissue by stimulating the host inflammatory response.

Objective Prenatal infection and postpartum inflammatory experiences have been associated with increased risk of schizophrenia. To explore whether prenatal immune activation and prepubertal inflammation have cumulative impact on vulnerability to schizophrenia. Methods Polyinosinin-polycytidylic acid was injected into pregnant mice to establish maternal immune activation models on gestation day 9.5. Offspring were treated with poly I:C during puberty or adulthood as the second hit. 1)Using ELISA and quantitative real-time PCR to detect inflammatory response after administration of poly Ⅰ:C. 2)The effects of single or combined exposure to prenatal immune activation and prepubertal inflammation were examined by prepulse inhibition and locomotor reactions to dizocilpine(MK-801). Behavioral assessment took place when the animals reached adulthood. Results 1)Offspring from poly Ⅰ:C -treated mothers showed sensorimotor gating deficiency, as well as in the precipitation of behavioral hypersensitivity to the drugs dizocilpine, which were similar with schizophrenia. The phenotype of female was more pronounced than male. 2)However, double-hit model's sensorimotor gating deficient level was lower than that of prenatal immune activation model, and the phenotype of schizophrenia was relieved after second hit. Conclusions There is no synergistic pathological effect of prenatal immune activation plus pre-pubertal or adulthood inflammation.

The growth of watermelon is often threatened by Fusarium oxysporum f. sp. niveum (Fon) in successively monocultured soil, which results in economic loss. The objective of this study was to investigate the effect of D123 wheat as a companion crop on soil enzyme activities, microbial biomass and microbial communities in the rhizosphere of watermelon and to explore the relationship between the effect and the incidence of wilt caused by Fon. The results showed that the activities of soil polyphenol oxidase, urease and invertase were increased, the microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) were significantly increased, and the ratio of MBC/MBN was decreased (P

Large areas of saline-alkaline land in China are polluted by phthalic acid esters (PAEs). Among the PAEs, dimethyl phthalate (DMP) is an important synthetic organic that seriously threatens human health. The objectives of this study are to investigate the biodegradation kinetics of DMP by a new bacterium, Bacillus sp. M7, isolated from saline-alkaline soil and to optimize the degradation rate of DMP using response surface methodology (RSM). Bacillus sp. M7 can utilize DMP as its sole carbon and energy source under high salinity and alkaline conditions. Results show that the biodegradation process fits well with a first-order kinetic model and the half-life of DMP degradation ranges from 0.8682 to 2.2696 d as the initial DMP concentration varies from 10 to 800 mg/L. The separate effects of pH, temperature, Na+ level and Fe2+ level on the kinetics of DMP biodegradation were also determined. Results of batch experiments show that the four environmental factors strongly affect DMP degradation. The DMP degradation rate decreases significantly at the levels > pH 9.0, > 40 °C, > 6 g/L Na+ or > 40 mg/L Fe2+. After optimization of the four factors using RSM, the DMP degradation rate increases by 32.4% than that under basic conditions and is maximized to 2.2771 mg/(L·h). This is the first report on the statistical optimization of DMP degradation rate. [ABSTRACT FROM AUTHOR]

The aim of this work was to assess the effect of atrazine on the microbial biomass and community diversity of black soils because the herbicide atrazine is applied intensively on black soils and may impact on the sustainability of black soils in China. A laboratory experiment was set up, and the associated parameters, such as residual atrazine, microbial biomass and microbial diversity, were determined. Residual amounts of atrazine remained at over 85.5% in all of the treatments throughout 95 d of observation. Compared to the controls, the microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) fluctuated tremendously throughout the incubation time. Atrazine disturbed not only the stability of microbial biomass in black soils, but also the microbial evenness, Shannon diversity and species richness decreased in black soils. The impact of atrazine on microbial diversity was positively correlated with the concentration of the contaminant. This study suggests that atrazine pollution may deteriorate black soils and disrupt their use in agriculture. [ABSTRACT FROM AUTHOR]

Dimethyl phthalate (DMP), a known endocrine disruptor and one of the phthalate esters (PAEs), is a ubiquitous pollutant. Its impacts on living organisms have aroused great concern. In this study, the impacts of DMP contamination on bacterial communities and functions were tested by using microcosm model in black soils. The results showed that the operational taxonomic unit (OTUs) richness and bacterial diversity were reduced by DMP contamination. The relative percentages of some genera associated with nitrogen metabolism were increased by DMP contamination, while the relative percentages of some other genera that were extremely beneficial to soil health were decreased by DMP contamination. Further, the relative percentages of some genera that possessed the capability to degrade DMP were increased by the DMP treatment at low concentrations (5, 10, and 20 mg/kg), but were decreased by the high concentration DMP treatment (40 mg/kg). Clearly, DMP contamination changed the bacterial community structure and disturbed the metabolic activity and functional diversity of the microbes in black soils. Our results suggest that DMP pollution can alter the metabolism and biodiversity of black soil microorganisms, thereby directly impact fertility and ecosystem functions. [ABSTRACT FROM AUTHOR]

The rice gene Xa21 confers resistance against Xanthomonas oryzae pv. oryzae ( Xoo). Xa21 encodes a receptor-like kinase (XA21). We demonstrate that XA21 autophosphorylates residues Ser686, Thr688 and Ser689 in vitro. Substitution of these residues with alanines did not affect the autophosphorylation function of this kinase, but specifically destabilized the resistance protein in vitro and in vivo. Plants carrying these same substitutions in XA21 were compromised in their resistance to the normally avirulent Xoo Philippine race 6. Additionally, we show that wild-type XA21 and the kinase-dead mutant with the invariable Lys736 residue mutated to glutamic acid were also proteolytically degraded in protein extracts. Finally, we show a correlation between the in vitro degradation and in vivo instability of the proteins. We propose that autophosphorylation of Ser686, Thr688 and Ser689 functions to stabilize XA21 against the developmentally controlled proteolytic activity. [ABSTRACT FROM AUTHOR]

The KNAT1 gene is a member of the Class I KNOX homeobox gene family and is thought to play an important role in meristem development and leaf morphogenesis. Recent studies have demonstrated that KNAT1/BP regulates the architecture of the inflorescence by affecting pedicle development in Arabidopsis thaliana. Herein, we report the characterization of an Arabidopsis T-DNA insertion mutant that shares considerable phenotypic similarity to the previously identified mutant brevipedicle ( bp). Molecular and genetic analyses showed that the mutant is allelic to bp and that the T-DNA is located within the first helix of the KNAT1 homeodomain (HD). Although the mutation causes a typical abnormality of short pedicles, propendent siliques, and semidwarfism, no obvious defects are observed in the vegetative stage. A study on cell morphology showed that asymmetrical division and inhibition of cell elongation contribute to the downward-pointing and shorter pedicle phenotype. Loss of KNAT/BP function results in the abnormal development of abscission zones. Microarray analysis of gene expression profiling suggests that KNAT1/BP may regulate abscission zone development through hormone signaling and hormone metabolism in Arabidopsis. (Managing editor: Ping He) [ABSTRACT FROM AUTHOR]

Ubiquitin-mediated protein modification plays a key role in many cellular signal transduction pathways. The Arabidopsis geneXBAT32encodes a protein containing an ankyrin repeat domain at the N-terminal half and a RING finger motif. The XBAT32 protein is capable of ubiquitinating itself. Mutation inXBAT32causes a number of phenotypes including severe defects in lateral root production and in the expression of the cell division markerCYCB1;1::GUS. TheXBAT32gene is expressed abundantly in the vascular system of the primary root, but not in newly formed lateral root primordia. Treatment with auxin increases the expression ofXBAT32in the primary root and partially rescues the lateral root defect inxbat32-1mutant plants. Thus, XBAT32 is a novel ubiquitin ligase required for lateral root initiation. [ABSTRACT FROM AUTHOR]

The genomic sequence of a rice (Oryza sativa L.) glycine-rich protein (GRP) gene, designated Osgrp-2, has been previously determined (GenBank U40708). Primer extension analysis indicated that transcription starts 47 bp upstream of the translation start codon. To gain an insight into the transcriptional regulation of this gene, the 2,401-bp promoter sequence and a series of its 5′ deletions were transcriptionally fused to the β-glucuronidase (GUS) gene. GUS activity was subsequently assayed in a transient expression system of tobacco (Nicotiana tabacum L.) protoplasts, which revealed the presence of a positive regulatory region (–2290 to –1406) and two negative regulatory regions (–2401 to –2291 and –1405 to –1022) in the Osgrp-2 promoter for the promoter activity. The positive regulatory region displayed an enhancer-like activity when fused to the cauliflower mosaic virus (CaMV) 35S minimal promoter (–89 to +6) to drive GUS expression and assayed on tobacco leaves by the Agrobacterium-mediated transient expression technique (agroinfiltration). Histochemical staining for GUS activity on transgenic tobacco plants has further indicated a preferential expression in vascular tissues of stems and leaves conferred by the positive regulatory region. A 1,023-bp fragment of the Osgrp-2 promoter (–1021 to +2) fused with GUS was transformed into tobacco and proved to be capable of conferring vascular-specific expression. Further 5′ and 3′ deletion analysis of the 1,023-bp promoter revealed that a 99-bp fragment located from –497 to –399 contained cis-elements responsible for vascular-specific expression. [ABSTRACT FROM AUTHOR]