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Microbial Cell Factories Mar 2023The lipopeptide herbicolin A (HA) secreted by the biocontrol agent Pantoea agglomerans ZJU23 is a promising antifungal drug to combat fungal pathogens by targeting lipid...
BACKGROUND
The lipopeptide herbicolin A (HA) secreted by the biocontrol agent Pantoea agglomerans ZJU23 is a promising antifungal drug to combat fungal pathogens by targeting lipid rafts, both in agricultural and clinical settings. Improvement of HA production would be of great significance in promoting its commercialization. This study aims to enhance the HA production in ZJU23 by combining fermentation optimization and strain engineering.
RESULTS
Based on the results in the single-factor experiments, corn steep liquor, temperature and initial pH were identified as the significant affecting factors by the Plackett-Burman design. The fermentation medium and conditions were further optimized using the Box-Behnken response surface method, and the HA production of the wild type strain ZJU23 was improved from ~ 87 mg/mL in King's B medium to ~ 211 mg/mL in HA induction (HAI) medium. A transposon library was constructed in ZJU23 to screen for mutants with higher HA production, and two transcriptional repressors for HA biosynthesis, LrhA and PurR, were identified. Disruption of the LrhA gene led to increased mRNA expression of HA biosynthetic genes, and subsequently improved about twofold HA production. Finally, the HA production reached ~ 471 mg/mL in the ΔLrhA mutant under optimized fermentation conditions, which is about 5.4 times higher than before (~ 87 mg/mL). The bacterial suspension of the ΔLrhA mutant fermented in HAI medium significantly enhanced its biocontrol efficacy against gray mold disease and Fusarium crown rot of wheat, showing equivalent control efficacies as the chemical fungicides used in this study. Furthermore, HA was effective against fungicide resistant Botrytis cinerea. Increased HA production substantially improved the control efficacy against gray mold disease caused by a pyrimethanil resistant strain.
CONCLUSIONS
This study reveals that the transcriptional repressor LrhA negatively regulates HA biosynthesis and the defined HAI medium is suitable for HA production. These findings provide an extended basis for large-scale production of HA and promote biofungicide development based on ZJU23 and HA in the future.
Topics: Pantoea; Fermentation; Genetic Engineering; Antifungal Agents; Biological Control Agents; Temperature; Hydrogen-Ion Concentration; Gene Expression Regulation, Bacterial; Culture Media; Bioreactors; Regression Analysis; Analysis of Variance; Reproducibility of Results; Repressor Proteins; Mycoses; Crops, Agricultural; Plant Diseases; Humans; Animals
PubMed: 36915090
DOI: 10.1186/s12934-023-02051-z -
Frontiers in Plant Science 2023Acquisition of the pathogenicity plasmid pPATH that encodes a type III secretion system (T3SS) and effectors (T3Es) has likely led to the transition of a non-pathogenic...
Acquisition of the pathogenicity plasmid pPATH that encodes a type III secretion system (T3SS) and effectors (T3Es) has likely led to the transition of a non-pathogenic bacterium into the tumorigenic pathogen . pv. () forms galls on gypsophila () and triggers immunity on sugar beet (), while pv. () causes galls on both gypsophila and sugar beet. Draft sequences of the and genomes were previously generated using the MiSeq Illumina technology and used to determine partial T3E inventories of and . Here, we fully assembled the and genomes following sequencing with PacBio technology and carried out a comparative sequence analysis of the and pathogenicity plasmids pPATH and pPATH. Assembly of and genomes revealed a ~4 Mbp chromosome with a 55% GC content, and three and four plasmids in and , respectively. pPATH and pPATH share 97% identity within a 74% coverage, and a similar GC content (51%); they are ~156 kb and ~131 kb in size and consist of 198 and 155 coding sequences (CDSs), respectively. In both plasmids, we confirmed the presence of highly similar gene clusters encoding a T3SS, as well as auxin and cytokinins biosynthetic enzymes. Three putative novel T3Es were identified in and one in . Among T3SS-associated proteins encoded by and , we identified two novel chaperons of the ShcV and CesT families that are present in both pathovars with high similarity. We also identified insertion sequences (ISs) and transposons (Tns) that may have contributed to the evolution of the two pathovars. These include seven shared IS elements, and three ISs and two transposons unique to . Finally, comparative sequence analysis revealed plasmid regions and CDSs that are present only in pPATH or in pPATH. The high similarity and common features of the pPATH plasmids support the hypothesis that the two strains recently evolved into host-specific pathogens.
PubMed: 37583594
DOI: 10.3389/fpls.2023.1198160 -
Frontiers in Microbiology 2020The species includes strains that are agronomically relevant for their growth-promoting or biocontrol traits. Molecular analysis demonstrated that the IPDC pathway...
The species includes strains that are agronomically relevant for their growth-promoting or biocontrol traits. Molecular analysis demonstrated that the IPDC pathway involved in the conversion of tryptophan (Trp) to indole-3-acetic acid (IAA) is highly conserved among strains at both gene and protein levels. Results also indicated that the promoter region controlling the inducible expression of gene differs from the model system , which is in accordance with the observation that accumulates higher levels of IAA when cells are collected in the exponential phase of growth. To assess the potential applications of these microorganisms for IAA production, C1, an efficient auxin-producer strain, was cultivated in 5 L fermenter so as to evaluate the effect of the medium formulation, the physiological state of the cells, and the induction timing on the volumetric productivity. Results demonstrated that higher IAA levels were obtained by using a saline medium amended with yeast extract and saccharose and by providing Trp, which acts both as a precursor and an inducer, to a culture in the exponential phase of growth. Untargeted metabolomic analysis revealed a significant effect of the carbon source on the exometabolome profile relative to IAA-related compounds and other plant bioactive signaling molecules. The IAA-enriched metabolites secreted in the culture medium by C1 were used as plant biostimulants to run a series of trials at a large-scale nursery farm. Tests were carried out with and systems following the regular protocols used for large-scale plant tree agamic propagation. Results obtained with 4,540 microcuttings of s rootstock GF/677 and 1,080 plantlets of L. showed that metabolites from strain C1 improved percentage of rooted-explant, number of adventitious root formation, plant survival, and quality of plant as vigor, with an increase in the leaf area between 17.5 and 42.7% compared to IBA-K (indole-3-butyric acid potassium salt)-treated plants.
PubMed: 32765438
DOI: 10.3389/fmicb.2020.01475 -
Microbiology Resource Announcements Aug 2022Here, we report the draft genome sequence of Pantoea agglomerans CPHN2, an endophyte isolated from nodules of Cicer arietinum (Chickpea) from Hisar, Haryana, India. The...
Here, we report the draft genome sequence of Pantoea agglomerans CPHN2, an endophyte isolated from nodules of Cicer arietinum (Chickpea) from Hisar, Haryana, India. The genome was 4,839,532 bp and exhibited a GC content of 55.2% and 4,508 genes with 4,468 coding sequences, 1 rRNA, 71 tRNAs, and 1 CRISPR.
PubMed: 35861538
DOI: 10.1128/mra.00192-22 -
Indian Journal of Dermatology,... 2022Pantoea agglomerans is a ubiquitous gram-negative bacterium that has been linked to skin and joint infections secondary to plant injuries. Herein we report a 58-year-old...
Pantoea agglomerans is a ubiquitous gram-negative bacterium that has been linked to skin and joint infections secondary to plant injuries. Herein we report a 58-year-old woman who presented with 2 erythematous nodules with purulent discharge on the anterior aspect of the right leg that developed after a penetrating plant injury. The patient was initially treated with amoxicillin-clavulanic acid, cloxacillin and clindamycin without improvement. P. agglomerans was isolated from both exudate and skin biopsy cultures. Healing of the lesions was achieved after the spontaneous release of a retained plant fragment and treatment with cotrimoxazole. Identification of P. agglomerans in persistent exudative lesions should alert the clinician regarding a possible previous plant injury and retained vegetal fragments. Conventional antibiotic treatment and the extraction of retained foreign bodies usually lead to complete resolution.
Topics: Anti-Bacterial Agents; Female; Humans; Middle Aged; Pantoea; Plants; Wound Healing; Wound Infection
PubMed: 33666040
DOI: 10.25259/IJDVL_1069_19 -
Foods (Basel, Switzerland) Apr 2022As a traditional Chinese rice wine, Hong Qu glutinous rice wine (HQW) is popular among consumers due to its unique flavor. However, its quality changes during...
As a traditional Chinese rice wine, Hong Qu glutinous rice wine (HQW) is popular among consumers due to its unique flavor. However, its quality changes during fermentation, and the potential relationships between flavor and microbes have not been systematically researched. In this work, physicochemical properties (pH, total sugar, alcohol, amino acid nitrogen), flavor compounds (organic acids, free amino acids, and volatile compounds), and microbial communities were investigated. The results revealed that , , , , and predominated the bacterial genera, and was the predominant fungal genus. Organic acids, free amino acids, and key volatile compounds (esters and alcohols) significantly increased during fermentation. The correlations analysis showed that was closely associated with flavor compounds formation. This study deepens our understanding of the roles of microorganisms in flavor formation on traditional HQW fermentation.
PubMed: 35454684
DOI: 10.3390/foods11081097 -
Heliyon Jul 2023Endophyte-assisted phytoremediation is an emerging technique for soil heavy metals (HMs) remediation and has become a research focus in the world because of the benefits...
Endophyte-assisted phytoremediation is an emerging technique for soil heavy metals (HMs) remediation and has become a research focus in the world because of the benefits of endophytes on plant growth and uptake of HMs. In this study, multifunctional endophytic bacteria strains were isolated and screened, and the feasibility of these strains for soil cadmium (Cd) remediation was investigated by soil incubation experiments and pot experiments. All endophytic bacteria were isolated from the roots of woody plants grown on Cd-contaminated soil. Seven endophytic bacteria strains had capacities to tolerate Cd toxicity and produce siderophores, and sequence analysis of the 16S rRNA gene classified these strains as belonging to the genera , , , and . All strains were able to produce hydroxamate siderophores (32.40%-91.49%) and had three or more plant growth promoting properties such as phosphorus solubilization, nitrogen fixation, indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase production. They were all strongly resistant to Cd toxicity, with the minimum inhibitory concentration in LB medium ranging from 1.5 mM to 9.0 mM. Except for strain JLS17, other strains showed decreasing removal rates within continuously elevated Cd concentration of 10-100 mg L. Compared with the uninoculated treatment, the inoculation of strains JLS17, JLS32, and JLS50 effectively increased the concentration of acid-soluble Cd and decreased the concentration of reducible, oxidizable, and residual Cd in the soils of different Cd contamination levels. In pot experiments, inoculation of strains JLS17 and YTG72 significantly ( < 0.05) promoted the growth of above-ground parts and root system of slash pine () under Cd stress. This study provides a valuable biological resource for endophyte-assisted phytoremediation and a theoretical basis for the application of endophytic bacteria for remediation of Cd-contaminated soil.
PubMed: 37539295
DOI: 10.1016/j.heliyon.2023.e17661 -
Microbial Biotechnology Sep 2020Given the important roles that seed-borne endophytes can play on their plant hosts, comprehensive studies of the bacterial and fungal communities of seeds are of great...
Given the important roles that seed-borne endophytes can play on their plant hosts, comprehensive studies of the bacterial and fungal communities of seeds are of great importance. In this study, we assessed the seed endophytes of three gramineous (Avena sativa, Elymus sibiricus and Elymus dahuricus) and four leguminous (Vicia villosa, Trifolium repens, Trifolium pretense and Medicago sativa) forages using high-throughput sequencing. In total, 1013 distinct bacterial operational taxonomic units (OTUs) and 922 fungal OTUs were detected, with bacteria and fungi per sample ranging from 240 to 425 and 261 to 463 respectively. These seven forages shared a high number of potentially beneficial taxa, including Bacillus, Pantoea, Candida and Helotiales, but the relative proportion of these taxa was different in each seed. Fungal communities were clustered more distinctively by host genotypes than bacterial. Some bacterial taxa may be involved in the recruitment of genera from the same phylum. Three Pantoea sp. and five Bacillus sp. were isolated from seeds, and all showed positive effects on Medicago sativa germination rate under salt stress, and of these, Bacillus subtilis Es-1 and Pantoea agglomerans Ed-3 performed best, but their influence was affected by the seed's microbiome. Rather than simply promoting host plant growth directly, some taxa may also participate in organizing the assembly of plant microbiomes which will influence seed response to biological factors. This study uses a new, high-throughput sequencing based strategy to identify beneficial strains and analyse the interactions between microorganisms and plants to maximize microbial functions in long-term agricultural practices.
Topics: Endophytes; Fabaceae; Fungi; Microbiota; Seeds
PubMed: 32643276
DOI: 10.1111/1751-7915.13618 -
The Canadian Journal of Infectious... 2022Bacterial biofilms are a big menace to industries and the environment and also in the health sector, accumulation of which is a major challenge. Despite intensive...
Bacterial biofilms are a big menace to industries and the environment and also in the health sector, accumulation of which is a major challenge. Despite intensive efforts to curb this issue, a definitive solution is yet to be achieved. Enzyme-templated disruption of the extracellular matrix of biofilm and its control and elimination are emerging as an efficient and greener strategy. The study describes the antibiofilm potential of alpha-amylase from the marine microorganism PCI05, against food-borne pathogens. Amylase exhibited stability in a wide pH range and retained 50% of its activity at temperatures as high as 100°C. Thermal analysis of the enzyme produced showed thermal stability, up to 130°C. From these findings, it can be envisaged that the alpha-amylase produced from can be used for starch liquefaction; it was also evaluated for antibiofilm activity. Amylase from this marine bacterium was found to efficiently disrupt the preformed biofilms of food-borne pathogens such as , , , , and serotype Typhi based on the value of biofilm inhibitory concentrations.
PubMed: 35462682
DOI: 10.1155/2022/7480382 -
BMC Genomic Data Apr 2022As part of a research aiming at the isolation of bacteria secreting growth inhibiting compounds, cultures of Francisella tularensis were implanted in environmental...
OBJECTIVE
As part of a research aiming at the isolation of bacteria secreting growth inhibiting compounds, cultures of Francisella tularensis were implanted in environmental samples and monitored for inhibition zones on agar. Two antibiotic-like secreting bacteria were isolated, their genomic sequence was deciphered and taxonomic profiling analysis classified them as belonging to the Pantoea genus.
DATA DESCRIPTION
Two bacterial isolates exhibiting growth inhibition zones to F. tularensis (LVS) were analyzed using the Oxford Nanopore Technology (ONT). Preliminary de novo assembly of the reads was performed, followed by taxonomic profiling based on Multi Locus Sequence Analysis (MLSA) and implementation of the Average Nucleotide Identity (ANI) measure. The genomic sequences resulted in the identification of two different Pantoea species, denoted EnvD and EnvH. Subsequent de novo genome assembly generated 5 and 10 contigs for EnvD and EnvH, respectively. The largest contig (4,008,183 bps and 3,740,753 bps for EnvD and EnvH, respectively), overlaps to a major extent to the chromosome of closely related Pantoea species. ANI values calculated for both isolates revealed two apparently new species of the Pantoea genus. Our study deciphered the identity of two bacteria producing antibiotic-like compounds, and the genomic sequence revealed they represent distinct Pantoea species.
Topics: Anti-Bacterial Agents; Israel; Pantoea; Phylogeny; Sequence Analysis, DNA; Whole Genome Sequencing
PubMed: 35448968
DOI: 10.1186/s12863-022-01049-7