Strain B2 Research Articles

Functional annotation of hypothetical proteins from the Exiguobacterium antarcticum strain B7 reveals proteins involved in adaptation to extreme environments, including high arsenic resistance.

Exiguobacterium antarcticum strain B7 is a psychrophilic Gram-positive bacterium that possesses enzymes that can be used for several biotechnological applications. However, many proteins from its genome are considered hypothetical proteins (HPs). These functionally unknown proteins may indicate important functions regarding the biological role of this bacterium, and the use of bioinformatics tools can assist in the biological understanding of this organism through functional annotation analysis. Thus, our study aimed to assign functions to proteins previously described as HPs, present in the genome of E. antarcticum B7. We used an extensive in silico workflow combining several bioinformatics tools for function annotation, sub-cellular localization and physicochemical characterization, three-dimensional structure determination, and protein-protein interactions. This genome contains 2772 genes, of which 765 CDS were annotated as HPs. The amino acid sequences of all HPs were submitted to our workflow and we successfully attributed function to 132 HPs. We identified 11 proteins that play important roles in the mechanisms of adaptation to adverse environments, such as flagellar biosynthesis, biofilm formation, carotenoids biosynthesis, and others. In addition, three predicted HPs are possibly related to arsenic tolerance. Through an in vitro assay, we verified that E. antarcticum B7 can grow at high concentrations of this metal. The approach used was important to precisely assign function to proteins from diverse classes and to infer relationships with proteins with functions already described in the literature. This approach aims to produce a better understanding of the mechanism by which this bacterium adapts to extreme environments and to the finding of targets with biotechnological interest.

Lasiosan, a new exopolysaccharide from Lasiodiplodia sp. strain B2 (MTCC 6000): Structural characterization and biological evaluation

Abstract Ascomycete fungi are promising biofactories producing bioactive compounds exhibiting diverse biological activities. In an ongoing search for bioactive potential of microorganisms from different ecological niches, a promising Lasiodiplodia sp. strain B2 (MTCC 6000) was identified as a producer of exopolysaccharide (designated as Lasiosan). The exopolysaccharide was purified and structurally characterized as glucomannan having glucose and mannose residues (ratio 1:1) with average molecular mass of 29.3 kDa. Lasiosan demonstrated promising antimicrobial and anti-biofilm activities by inhibiting the growth of different Gram-negative, Gram-positive, drug-resistant bacteria and different Candida strains. The purified exopolysaccharide exhibited potential antioxidant activity in terms of good reducing power and scavenging of DPPH free radicals, superoxide anions and lipid peroxyl radicals. Further, the in vitro immune responses of Lasiosan were demonstrated in mouse RAW 264.7 macrophages. Lasiosan inhibited the LPS-stimulated reactive oxygen species (ROS) and nitric oxide (NO) generation in RAW 264.7 macrophages without affecting cell proliferation. Furthermore, Lasiosan significantly down-regulated the production of LPS stimulated proinflammatory mediators such as TNF-α and IL-6 from RAW 264.7 macrophages. This is the first report on Lasiosan exhibiting broad spectrum antimicrobial, anti-biofilm, antioxidant and immunomodulatory activities, which could be explored as a promising candidate for application in biotechnological and biomedical fields.

KatG plays an important role in Aeromonas hydrophila survival in fish macrophages and escape for further infection

The success of the pathogenic bacteria is partly attributable to their ability to thwart host innate immune responses, which includes resisting the antimicrobial functions of macrophages. And reactive oxygen species (ROS) is one of the most effective antimicrobial components of macrophages to kill invading bacteria. Our previous studies found that Aeromonas hydrophila can survive in fish macrophages, which suggested that this bacterium might take fish macrophages as their shelters to resist drug killings and other immune damage. But how A. hydrophila survive in host macrophages remains unknown. Since KatG has been reported to have not only catalase activity but also peroxidase and peroxynitritase activity, the amino acid sequence and protein structure of KatG was analyzed in this study, the function of KatG in A. hydrophila survival in and escape from host macrophages was also carried out. The bioinformatics analysis displayed that KatG of A. hydrophila B11 showed >93% homologous to that of KatG in other Aeromonas. KatG of A. hydrophila was stable silenced by shRNA and RT-qPCR confirmed the expression of KatG in KatG-RNAi was significantly reduced. The survival rate of intracellular KatG-RNAi decreased by 80% compared to that of the wild type strain B11, while the intracellular ROS level of the macrophages that phagocytosed KatG-RNAi increased 65.9% when compared to that of the macrophages phagocytosed wild-type strain. The immune escape rate of A. hydrophila decreased by 85% when the expression of KatG was inhibited. These results indicated that (1) The amino acid sequence and protein structure of KatG of A. hydrophila is conserved; (2) KatG helped A. hydrophila to survive in fish macrophages by eliminating the harm of intracellular H2O2 and inhibiting intracellular ROS levels increased; (3) A small portion of intracellular A. hydrophila could escape from host macrophages for further infection, in this process KatG also played important role.

Genome Sequence of Methylotrophic Azospirillum sp. Strain B2, Isolated from a Raised Sphagnum Bog.

ABSTRACTAzospirillum sp. strain B2 is a soil bacterium which was originally isolated from the Sosvyatskoe raised Sphagnum bog in Russia. Here, we present the approximately 8-Mb draft genome sequence of Azospirillum sp. B2, with the aim of providing insight into the genomic basis of its ecological success in peatland settings.

Comparative transcription profiling of two fermentation cultures of Xanthomonas campestris pv. campestris B100 sampled in the growth and in the stationary phase.

The ɣ-proteobacterium Xanthomonas campestris pv. campestris (Xcc) is the producer of the biopolymer xanthan, a polysaccharide which is used as a thickener in numerous industrial applications. In this study, we present a global transcriptome profiling of two Xcc strain B100 cultures obtained from fermentation during the growth phase and the subsequent stationary phase associated with xanthan biosynthesis. During the xanthan production phase, highly abundant transcripts belonged to genes encoding for small RNAs, glycogen biosynthesis, and xanthan export. A total of 1850 (40%) genes were differentially transcribed during the stationary phase where 924 were transcriptionally up-regulated and 926 genes were down-regulated. An overview of differentially transcribed genes includes a significant down-regulation of genes involved in transcription, translation, and amino acid biosynthesis pathways. A group of up-regulated genes was involved in cellular response against oxidative stress, such as those coding for superoxide dismutase and catalase. Genes encoding enzymes involved in nucleotide sugar precursor synthesis of xanthan biosynthesis, such as xanA, galU, and ugd, exhibited a transcription pattern that did not change during the growth and stationary phase. Regarding the transcription pattern of the gum gene cluster that govern xanthan biosynthesis, a significant up-regulation of the genes gumB, gumC, and gumD was observed, while the transcript pools of the genes gumG, gumH, gumI, and gumJ were reduced and those of genes gumE, gumF, gumK, gumL, and gumM remained un-changed during the stationary phase compared to the growth phase. The obtained data represents the first analysis of gene expression patterns under xanthan production conditions and provides the bases for future studies aiming at enhancing xanthan yield.

Enterobacter cloacae administration induces hepatic damage and subcutaneous fat accumulation in high-fat diet fed mice.

Accumulating evidence indicates that gut microbiota plays a significant role in obesity, insulin resistance and associated liver disorders. Family Enterobacteriaceae and especially Enterobacter cloacae strain B29 have been previously linked to obesity and hepatic damage. The underlying mechanisms, however, remain unclear. Therefore, we comprehensively examined the effects of E. cloacae subsp. cloacae (ATCC® 13047™) administration on host metabolism of mice fed with high-fat diet (HFD). C57BL/6N mice were randomly divided into HFD control, chow control, and E. cloacae treatment groups. The E. cloacae treatment group received live bacterial cells in PBS intragastrically twice a week, every other week for 13 weeks. Both control groups received PBS intragastrically. After the 13-week treatment period, the mice were sacrificed for gene and protein expression and functional analyses. Our results show that E. cloacae administration increased subcutaneous fat mass and the relative proportion of hypertrophic adipocytes. Both subcutaneous and visceral fat had signs of decreased insulin signaling and elevated lipolysis that was reflected in higher serum glycerol levels. In addition, E. cloacae -treated mice had significantly higher hepatic AST and AST/ALT ratio, and their liver histology indicated fibrosis, demonstrating that E. cloacae subsp. cloacae administration promotes hepatic damage in HFD fed mice.

Complete Genome Sequence of Altererythrobacter sp. Strain B11, an Aromatic Monomer-Degrading Bacterium, Isolated from Deep-Sea Sediment under the Seabed off Kashima, Japan.

ABSTRACTAltererythrobacter sp. strain B11 is an aromatic monomer-degrading bacterium newly isolated from sediment under the seabed off Kashima, Japan, at a depth of 2,100 m. Here, we report the complete nucleotide sequence of the genome of strain B11.

Identification and characterization of a new Bacillus atrophaeus strain B5 as biocontrol agent of postharvest anthracnose disease in soursop (Annona muricata) and avocado (Persea americana)

Anthracnose is a fungal disease caused by Colletotrichum species that is detrimental to numerous fruit, including soursop and avocado. The use of fungicides to maintain the high quality of fruit creates a potential health risk. One alternative to this problem is the biological control, which has been applied successfully during postharvest. The Bacillus species are one of the most studied biological agents against postharvest pathogens because accomplish their biocontrol performance by producing a variety of metabolites. In this study, we evaluated the activity of metabolites contained in the cell free supernatant, obtained from Bacillus strain B5 culture, against micelial growth and spore germination of two virulent strains of C. gloeosporioides isolated from soursop and avocado. On the basis of 16S rDNA gene sequence analysis, this strain was identified as Bacillus atrophaeus. A preventive treatment using cell free supernatant, reduced severity and incidence of anthracnose disease on harvested soursop and avocado fruit. B. atrophaeus strain B5 harbors genes involved in the production of antibiotics such as surfactin, bacillomycin and iturin, which could be contributing to the efficiency of the preventive treatment during postharvest. The antagonistic role of metabolites contained in the cell free supernatant against anthracnose disease, provide a new approach by which to attack this problem and can help reduce the use of chemical pesticides, environmental pollution, leading to the safer fruit preservation.

Efficient degradation of triclosan by an endophytic fungus Penicillium oxalicum B4

Triclosan (TCS), a widely used antimicrobial and preservative agent, is an emerging contaminant in aqueous and soil environment. Microbial degradation of TCS has not been reported frequently because of its inhibition of microbe growth. To explore the new microbial resources for TCS biodegradation, fungal endophytes were isolated and screened for the degradation potential. The endophytic strain B4 isolated from Artemisia annua L. showed higher degradation efficiency and was identified as Penicillium oxalicum based on its morphology and ITS sequences of ribosomal DNA. In both medium and synthetic wastewater, TCS (5mg/L) was almost completely degraded within 2h by the strain B4. The high capacity of TCS uptake (127.60 ± 8.57mg/g dry weight, DW) of fungal mycelium was observed during the first 10min after TCS addition. B4 rapidly reduced initial content (5.00mg/L) of TCS to 0.41mg/L in medium in 10min. Then, the accumulation of TCS in mycelium was degraded from 0.45 to 0.05mg/g DW after 1-h treatment. The degradation metabolites including 2-chlorohydroquinone, 2, 4-dichloropheno, and hydroquinone were found to be restrained in mycelia. The end products of the biodegradation in medium showed no toxicity to Escherichia coli. The new characteristics of high adsorption, fast degradation, and low residual toxicity highlight the potential of endophytic P. oxalicum B4 in TCS bioremediation.

ИЗУЧЕНИЕ ДЕЗИНФЕКЦИОННОЙ ЭФФЕКТИВНОСТИ СРЕДСТВА ПАЛОЦИД ДЛЯ ОБЕЗЗАРАЖИВАНИЯ ОБЪЕКТОВ ВЕТЕРИНАРНОГО НАДЗОРА

The results of laboratory and production tests of the effectiveness of the disinfectant Palocid for the disinfection of objects of veterinary supervision are presented. As test microorganisms were used the museum cultures of E. coli (strain 1257), Staphylococcus aureus (strain 209-P), bacilli (strain B5), B. cereus (strain 96). Inactivated blood serum of the horse was used to simulate natural contamination of surfaces. The quality of the disinfection was controlled by examining the washings from the test and control test objects for the presence of a given test culture. The results of laboratory and industrial tests show that Palocid is an effective disinfectant and can be recommended for preventive and forced disinfection in livestock, poultry, fur farming, automobile and railway transport, while monitoring its quality in the isolation of bacteria of the E. coli and staphylococcus group, as well as forced disinfection at the objects of veterinary supervision for infectious diseases of bacterial (including tuberculosis) and viral etiology, especially dangerous infections (anthrax and other spore infections).

ОЦЕНКА ЭФФЕКТИВНОСТИ ДЕЗИНФИЦИРУЮЩЕГО СРЕДСТВА ФОРБИЦИД

The article presents positive results of laboratory and industrial studies of a new disinfecting drug of domestic origin, Forbicide, LLC PC Vortex Laboratory test were carried out on test objects made of wood, cements, stainless steel, as well, as on metlakh and tiles. The museum cultures of E. coli (strain 1257), S. aureus (strain 209-P), Mycobacterium (strain B5), B. cereus (strain 96) were used as test microorganisms. To simulate the natural contamination of the surfaces, inactivated blood serum of the horse was taken, which was applied on the test surface at the rate of 0,5 g/100sm2. The research showed that Forbicide is an effective disinfectant and can be used for forced and preventive disinfection at veterinary surveillance sites.

Virulent Entomopathogenic Fungi against The Two-Spotted Spider Mite Tetranychus urticae and some Associated Predator Mites as Non Target Organisms

Entomopathogenic fungi and predatory mites can independently contribute to control the two-spotted spider mite Tetranychus urticae Koch. It is important to assess the risk of possible fungal infections in predators when a combination of them are being considered as a tandem control strategy for T. urticae in IPM program.The first part of this study tested 4 Beauveria bassiana isolates and 2 Metarhizium anisopliae for virulence against T. urticae, egg and adult stages. Strains B4 was found to be the most potent toward egg and adult stages, causing 88.5% mortality for the adult stage at a concentration of 108 spores/ml. and the LC50 was 6.61x 106. When applied on the egg stage the hatchability was 25.2% compared with the control which reached 99% and the LC50 was 1.14 x107. The second part evaluated the pathogenicity of the most effective isolates B4, three concentrations were applied LC25, LC50 and LC90 against the adult of the two predator mites Phytoseiulus persimilis and Neoseiulus californicus. The bioassay results indicated that the isolate B4 was harmless against P. persimilis and slightly harmful against N. californicus. No viable fungal hyphae were found on predator cadavers. Observations with scanning electron microscopy revealed that conidia were attached to the cuticle of predatory mites within 24 h after spraying with strain B4, and had germinated within 24–48 h. After 48 h, conidia had gradually been shed from the mites, after none of the conidia had penetrated the cuticular surfaces. In contrast, the germinated conidia successfully penetrated the cuticle of T. urticae, and within 72 h the fungus colonized the mite’s body. Our study demonstrated that although several B. bassiana strains displayed a high virulence in T. urticae there was no evident pathogenicity to phytoseiid mites. These findings support the potential use of entomopathogenic fungus in combination with predatory mites in T. urticae control programs.

Effect of Bacillus spp. on Gerbera plant growth and control of Meloidogyne incognita

A greenhouse experiment was conducted to evaluate the efficacy of Bacillus spp. against Meloidogyne incognita (Kofoid and White) Chitwood infesting gerbera plants (Var. Valletta). Investigations were undertaken in pots filled with 5 kg of sterilized potting mixture consisting of red soil:sand:FYM (2:1:1 v/v) to assess the effect of liquid and talc formulations of Bacillus spp. viz., B. subtilis strain BG42, B. subtilis strain BG37 and B. amyloliquefaciens strain B4. The results indicated that Soil drenching of liquid formulation of B. subtilis strain BG42 @ 1%/m2 (1x108 colony forming units/g) gave maximum reduc-tion of juveniles per 250g soil (67.40%), number of adult females/5g root (73.46%), number of eggmass/5g root (69.44%), gall index (1.67) and increased flower yield/m2 (127.03%). Soil drenching of liquid formulation of B. subtilis strain BG 37 were next in line in efficacy. Further liquid formulation of B. subtilis strain BG42 had a positive influence on growth parameters viz., shoot length, root length, shoot and root weight, number of leaves / plant and flower yield/m2 and quality parameters viz., flower diameter, colour of the flower, length of flower stalk and vase life . The endophytic colonization potential of the Bacillus spp. introduced into the soil was confirmed by reisolating them from gerbera roots.

Biological control of septoria leaf blotch and growth promotion in wheat by Paenibacillus sp. strain B2 and Curtobacterium plantarum strain EDS

Many of the non-pathogenic endophytic bacteria that reside in plant roots promote plant growth as well as protection against pathogens attack. However, little is known about their mode of action in wheat. We have previously demonstrated the potential of Paenibacillus sp. strain B2 (PB2) to stimulate plant defense mechanisms via its paenimyxin lipo-polypeptide elicitor. Recently, we isolated the Curtobacterium plantarum strain EDS (EDS) from seeds of almost all wheat cultivars. In the present work, the ability of PB2 and EDS to promote wheat growth and protection against Septoria leaf blotch (SLB) was investigated. Results showed that PB2 is a general root external colonizer and cultivar-dependent endophyte. In the endophytic state and only in co-inoculation, it significantly increased the internal root colonization by EDS, resulting in an increase of root and aerial part fresh weights. qPCR analysis showed that, in the endophytic and nonendophytic states, PB2 conferred ≥59% protection against SLB by inducing systemic resistance which is characterized by the over expression of the pr1, lox, Aos, peroxidase, oxo and gst genes. Paenimyxin conferred 76% local protection characterized by the overexpression of the glu, lox, aos, pal, chs, oxo, and gst genes, and 82% systemic protection by chs. It was concluded that PB2 is potentially very interesting in the biocontrol of SLB and, in a mixture with EDS, in the wheat growth promoting. Genes involved in the flavonoid, salicylic acid, jasmonic acid, reactive oxygen species and basal defense pathways seem to play an important role in the resistance against SLB.

Sequence comparison of phoR, gyrB, groEL, and cheA genes as phylogenetic markers for distinguishing Bacillus amyloliquefaciens and B. subtilis and for identifying Bacillus strain B29.

Given the close genetic relationship between Bacillus amyloliquefaciens and B. subtilis, distinguishing the two solely based on their physiological and biochemical characteristics and 16S rRNA sequences is difficult. Molecular identification was used to discover suitable genes for distinguishing the two bacteria, and to identify the bio-controlling strain B29, due to molecular identification has been paid more and more attention. The similarity of four genes, cheA, gyrB, groEL and phoR, of the two species was compared by the software BLASTN and MAGA, and phylogenetic tree was constructed. The B29 strain was re-identified by using the screened genes. The similarities of the four genes, gyrB, groEL, cheA and phoR, of the two species were 93-95%, 82-84%, 76-78% and 76-77%, respectively. The homologies of the four genes of the strain B29 and the strains of B. amyloliquefaciens strains were more than 95%. We determined how well the phoR and cheA genes could be used to differentiate B. amyloliquefacien and B. subtilis. The previously isolated biological control strain B29, initially classified as B. subtilis, was re-classified as B. amyloliquefaciens. Our data indicate that other than the phoR gene, the cheA gene might be a useful phylogenetic marker for differentiating B. subtilis and B. amyloliquefaciens.

Refined annotation of the complete genome of the phytopathogenic and xanthan producing Xanthomonas campestris pv. campestris strain B100 based on RNA sequence data

Bioinformatics tools and gene expression data were applied to identify new genes and to enhance the accuracy in genomic feature predictions for Xanthomonas campestris pv. campestris (Xcc) B100, a pathogen of cruciferous plants and model strain for the biosynthesis of xanthan, a polysaccharide with a multitude of commercial applications as a thickening agent. Results from 5′-enriched end RNA sequencing (RNA-seq) and total transcriptome RNA-seq experiments were used for this purpose. Functional gene annotations were updated where new evidence had emerged and start codon predictions were enhanced for 153 protein-coding genes (CDS). In total, 32 novel CDS, and 176 novel RNA genes and features were predicted, among them 77 isogenes of the small non-coding RNA sX9. Furthermore, the RNA-seq data facilitated the identification of 848 operons that included a total of 2551 CDS besides 1667 CDS that were mono-cistronically expressed.

Isolation and Characterization of Hydrocarbon-utilizing Bacteria from Petroleum Sludge Samples obtained from Crude Oil Processing Facility in Nigeria

The isolation and characterization of hydrocarbon-utilizing bacteria from petroleum oily sludge collected from crude oil processing plant in Rivers State, Nigeria was carried out. Microbiological analysis of the sludge sample showed that the microbial load consisted average of 2.5 x 106 cfu/g total heterotrophic bacterial (THB) count, while the hydrocarbon utilizing bacterial (HUB) count was average of 2.0 x 103 cfu/g. Phenotypic characteristics and phylogenetic analysis of the 16S rRNA gene sequence of the isolates revealed that they were related to members of the species Klebsiella pneumonia, Klebsiella oxytoca and Alcaligenes faecalis. The 16S rRNA of the isolates showed percentage similarities to the type strains (99% sequence similarities) of the following; Klebsiella pneumonia strain B21 (gi: 922317936), Klebsella pneumonia strain ICB-C183 (gi: 908478837), Klebsella oxytoca strain BCNAI (gi: 846993354), Klebsella oxytoca strain BC4 (gi: 884060138), Alcaligenes faecalis strain IOU PMR (gi: 686028963) and Alcaligenes faecalis strain AQ-I (gi: 816845513). Of the six hydrocarbon utilizing bacteria identified, 4(67%) were Klebsiella species while 2(33%) were identified as Alcaligenes sp of different strains. The result suggest that these isolated organisms from the petroleum sludge can be explored and used to promote environmentally friendly technology clean-up of petroleum hydrocarbon polluted sites in the Niger Delta region of Nigeria.Keywords: Hydrocarbon -utilizing bacteria, Petroleum sludge, 16S rRNA, Phylogenetic, Gene sequence.

Draft Genome Sequence and Assembly of a Lysobacter enzymogenes Strain with Biological Control Activity against Root Knot Nematodes.

ABSTRACTLysobacter enzymogenes strain B25, an isolate from an agricultural field, acts as a biological control agent against root knot nematodes in tomato plants. B25 also controls several fungal diseases and promotes plant growth under abiotic stress. We hereby report on the draft genome sequence and assembly of B25.

Proteomic analysis of organic sulfur compound utilisation in Advenella mimigardefordensis strain DPN7T.

2-Mercaptosuccinate (MS) and 3,3´-ditiodipropionate (DTDP) were discussed as precursor substance for production of polythioesters (PTE). Therefore, degradation of MS and DTDP was investigated in Advenella mimigardefordensis strain DPN7T, applying differential proteomic analysis, gene deletion and enzyme assays. Protein extracts of cells cultivated with MS, DTDP or 3-sulfinopropionic acid (SP) were compared with those cultivated with propionate (P) and/or succinate (S). The chaperone DnaK (ratio DTDP/P 9.2, 3SP/P 4.0, MS/S 6.1, DTDP/S 6.2) and a Do-like serine protease (DegP) were increased during utilization of all organic sulfur compounds. Furthermore, a putative bacterioferritin (locus tag MIM_c12960) showed high abundance (ratio DTDP/P 5.3, 3SP/P 3.2, MS/S 4.8, DTDP/S 3.9) and is probably involved in a thiol-specific stress response. The deletion of two genes encoding transcriptional regulators (LysR (MIM_c31370) and Xre (MIM_c31360)) in the close proximity of the relevant genes of DTDP catabolism (acdA, mdo and the genes encoding the enzymes of the methylcitric acid cycle; prpC,acnD, prpF and prpB) showed that these two regulators are essential for growth of A. mimigardefordensis strain DPN7T with DTDP and that they most probably regulate transcription of genes mandatory for this catabolic pathway. Furthermore, proteome analysis revealed a high abundance (ratio MS/S 10.9) of a hypothetical cupin-2-domain containing protein (MIM_c37420). This protein shows an amino acid sequence similarity of 60% to a newly identified MS dioxygenase from Variovorax paradoxus strain B4. Deletion of the gene and the adjacently located transcriptional regulator LysR, as well as heterologous expression of MIM_c37420, the putative mercaptosuccinate dioxygenase (Msdo) from A. mimigardefordensis, showed that this protein is the key enzyme of MS degradation in A. mimigardefordensis strain DPN7T (KM 0.2 mM, specific activity 17.1 μmol mg-1 min-1) and is controlled by LysR (MIM_c37410).

Biocontrol of grapevine aerial and root pathogens by Paenibacillus sp. strain B2 and paenimyxin in vitro and in planta

Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of Sorghum bicolor, was previously shown to possess antagonistic activity against fungi and bacteria due to the secretion of the peptide paenimyxin. The effects of strain B2 and paenimyxin were assessed against grapevine pathogens as they potentially represent a non-polluting complement or an alternative biocontrol agent to existing disease management strategies. In this study, the effects of Paenibacillus sp. strain B2 and paenimyxin were analyzed in vitro or in planta on the aerial or root pathogens of grapevine Botrytis cinerea, Plasmopara viticola and Xiphinema index. The bacterium significantly reduced B. cinerea development in vitro, and substantially decreased X. index numbers in soil and gall formation in the root system of grapevine plants. In vitro, paenimyxin inhibited the mycelial growth of B. cinerea, the mobility of the zoospores of P. viticola and X. index activity. Supplying paenimyxin at the time of inoculation of leaf tissue with P. viticola decreased infection sites, compared to application prior to fungal inoculation. Using the P. viticola/grapevine pathosystem, we showed that paenimyxin acts as a biopesticide against the oomycete but does not trigger plant defense. Conversely, Paenibacillus sp. strain B2 can induce the expression of the defense genes CHI (chitinase), PR-3 (proteinase inhibitor) and LOX (lipoxygenase). Altogether, the results obtained highlight the interest of Paenibacillus sp. strain B2 and paenimyxin for the biocontrol of different grapevine diseases.