-
Environment International May 2024The spread of antibiotic resistance genes (ARGs) in agroecosystems through the application of animal manure is a global threat to human and environmental health....
Priority establishment of soil bacteria in rhizosphere limited the spread of tetracycline resistance genes from pig manure to soil-plant systems based on synthetic communities approach.
The spread of antibiotic resistance genes (ARGs) in agroecosystems through the application of animal manure is a global threat to human and environmental health. However, the adaptability and colonization ability of animal manure-derived bacteria determine the spread pathways of ARG in agroecosystems, which have rarely been studied. Here, we performed an invasion experiment by creating a synthetic communities (SynCom) with ten isolates from pig manure and followed its assembly during gnotobiotic cultivation of a soil-Arabidopsis thaliana (A. thaliana) system. We found that Firmicutes in the SynCom were efficiently filtered out in the rhizosphere, thereby limiting the entry of tetracycline resistance genes (TRGs) into the plant. However, Proteobacteria and Actinobacteria in the SynCom were able to establish in all compartments of the soil-plant system thereby spreading TRGs from manure to soil and plant. The presence of native soil bacteria prevented the establishment of manure-borne bacteria and effectively reduced the spread of TRGs. Achromobacter mucicolens and Pantoea septica were the main vectors for the entry of tetA into plants. Furthermore, doxycycline stress promoted the horizontal gene transfer (HGT) of the conjugative resistance plasmid RP4 within the SynCom in A. thaliana by upregulating the expression of HGT-related mRNAs. Therefore, this study provides evidence for the dissemination pathways of ARGs in agricultural systems through the invasion of manure-derived bacteria and HGT by conjugative resistance plasmids and demonstrates that the priority establishment of soil bacteria in the rhizosphere limited the spread of TRGs from pig manure to soil-plant systems.
Topics: Manure; Animals; Soil Microbiology; Swine; Rhizosphere; Tetracycline Resistance; Arabidopsis; Bacteria; Gene Transfer, Horizontal; Anti-Bacterial Agents
PubMed: 38728817
DOI: 10.1016/j.envint.2024.108732 -
Applied and Environmental Microbiology Jun 2024
PubMed: 38722171
DOI: 10.1128/aem.00629-24 -
Microbial Ecology Apr 2024Here, we demonstrate the beneficial effect of surfactant-producing pseudomonads on Pantoea eucalypti 299R. We conducted a series of experiments in environments of...
Here, we demonstrate the beneficial effect of surfactant-producing pseudomonads on Pantoea eucalypti 299R. We conducted a series of experiments in environments of increasing complexity. P. eucalypti 299R (Pe299R), and Pseudomonas sp. FF1 (Pff1) or Pe299R and surfactant-production deficient Pseudomonas sp. FF1::ΔviscB (Pff1ΔviscB) were co-inoculated in broth, on swarming agar plates, and on plants. In broth, there were no differences in the growth dynamics of Pe299R when growing in the presence of Pff1 or Pff1ΔviscB. By contrast, on swarming agar plates, Pe299R was able to co-swarm with Pff1 which led to a significant increase in Pe299R biomass compared to Pe299R growing with Pff1ΔviscB or in monoculture. Finally in planta, and using the single-cell bioreporter for reproductive success (CUSPER), we found a temporally distinct beneficial effect of Pff1 on co-inoculated Pe299R subpopulations that did not occur in the presence of Pff1ΔviscB. We tested three additional surfactant-producing pseudomonads and their respective surfactant knockout mutants on PE299R on swarming agar showing similar results. This led us to propose a model for the positive effect of surfactant production during leaf colonization. Our results indicate that co-motility might be common during leaf colonization and adds yet another facet to the already manyfold roles of surfactants.
Topics: Pantoea; Pseudomonas; Surface-Active Agents
PubMed: 38683223
DOI: 10.1007/s00248-024-02381-4 -
Impact of bacterial volatiles on the plant growth attributes and defense mechanism of rice seedling.Heliyon Apr 2024Rice is a major dietary element for about two billion people worldwide and it faces numerous biotic and abiotic stress for its cultivation. Rice blast disease caused by...
Rice is a major dietary element for about two billion people worldwide and it faces numerous biotic and abiotic stress for its cultivation. Rice blast disease caused by reduce up to 30 % rice yield. Overuse of synthetic chemicals raises concerns about health and environment; so, there is an urgent need to explore innovative sustainable strategies for crop productivity. The main aim of this study is to explore the impact of bacterial volatiles (BVCs) on seedling growth and defense mechanisms of rice under condition. On the basis of plant growth promoting properties, six bacterial strains were selected out of ninety-one isolated strains for this study; BHUJPVR01, BHUJPVR02, sp. BHUJPVR12, BHUJPVR13, sp. BHUJPVWRO5 and sp. BHUJPVWLE7. Through the emission of bacterial volatiles compounds (BVCs), sp., and significantly reduces the growth of rice blast fungus by 69.20 %, 66.15 % and 62.31 % respectively. Treatment of rice seedlings with BVCs exhibited significant enhancement in defence enzyme levels, including guaiacol peroxidase, polyphenol oxidase, total polyphenols, and total flavonoids by a maximum of up to 24 %, 48 %, 116 % and 80 %, respectively. Furthermore, BVCs effectively promote shoot height, root height, and root counts of rice. All BVCs treated plant showed a significant increase in shoot height. treated plants showed the highest increase of 60 % shoot and 110 % root length, respectively. Root counts increased up to 30% in plants treated with and sp. The BVCs can be used as a sustainable approach for enhancing plant growth attributes, productivity and defence mechanism of rice plant under biotic and abiotic stresses.
PubMed: 38660266
DOI: 10.1016/j.heliyon.2024.e29692 -
Environmental Science and Pollution... May 2024Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore...
Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore are formed extracellularly and diffuse through porins across membranes into bacterial cells. Siderophores can bind heavy metals facilitating their influx into cells via the same mechanism. The aim of the studies was to determine the ability of siderophore-producing bacteria isolated from soils in the north-west part of Wedel Jarlsberg Land (Spitsbergen) to chelate non-Fe metals (Al, Cd, Co, Cu, Hg, Mn, Sn, and Zn). Specially modified blue agar plates were used, where Fe was substituted by Al, Cd, Co, Cu, Hg, Mn, Sn, or Zn in metal-chrome azurol S (CAS) complex, which retained the blue color. It has been proven that 31 out of 33 strains were capable of producing siderophores that bind to Fe, as well as other metals. Siderophores from Pantoea sp. 24 bound only Fe and Zn, and O. anthropi 55 did not produce any siderophores in pure culture. The average efficiency of Cd, Co, Cu, Mn, Sn, and Zn chelation was either comparable or higher than that of Fe, while Al and Hg showed significantly lower efficiency. Siderophores produced by S. maltophilia 54, P. luteola 27, P. luteola 46, and P. putida 49 exhibited the highest non-Fe metal chelation activity. It can be concluded that the siderophores of these bacteria may constitute an integral part of the metal bioleaching preparation, and this fact will be the subject of further research.
Topics: Siderophores; Soil Pollutants; Biodegradation, Environmental; Soil Microbiology; Metals, Heavy; Soil; Bacteria
PubMed: 38652189
DOI: 10.1007/s11356-024-33356-0 -
Environmental Microbiology Reports Apr 2024The seed-endophytic bacterial community is a potentially beneficial and heritable fraction of the plant microbiome. Its utilization as a sustainable crop improvement...
The seed-endophytic bacterial community is a potentially beneficial and heritable fraction of the plant microbiome. Its utilization as a sustainable crop improvement strategy could be especially valuable for species such as hemp, where production is being scaled up and new challenges will be faced in managing crop productivity and health. However, little is known about the makeup and variation of the hemp seed microbiome. This study profiled the endophytic bacterial communities harboured by 16 hemp cultivars sourced from commercial suppliers in Europe. A 16S rDNA amplicon sequencing approach identified 917 amplicon sequence variants across samples. Taxonomic classification of sequences revealed 4 phyla and 87 genera to be represented in the dataset. Several genera were widespread while some were specific to one or a few cultivars. Flavobacterium, Pseudomonas, and Pantoea were notable in their high overall abundance and prevalence, but community composition was variable and no one taxon was universally abundant, suggesting a high degree of flexibility in community assembly. Taxonomic composition and alpha diversity differed among cultivars, though further work is required to understand the relative influence of hemp genetic factors on community structure. The taxonomic profiles presented here can be used to inform further work investigating the functional characteristics and potential plant-growth-promoting traits of seed-borne bacteria in hemp.
Topics: Cannabis; Bacteria; Seeds; Endophytes; RNA, Ribosomal, 16S; Microbiota; Phylogeny; Biodiversity; Europe; DNA, Bacterial
PubMed: 38649235
DOI: 10.1111/1758-2229.13259 -
Bioresources and Bioprocessing May 2023The first-cured tobacco contains macromolecular substances with negative impacts on tobacco products quality, and must be aged and fermented to mitigate their effects on...
The first-cured tobacco contains macromolecular substances with negative impacts on tobacco products quality, and must be aged and fermented to mitigate their effects on the tobacco products quality. However, the natural fermentation takes a longer cycle with large coverage area and low economic efficiency. Microbial fermentation is a method to improve tobacco quality. The change of chemical composition of tobacco during the fermentation is often correlated with shapes of tobacco. This study aimed to investigate the effects of tobacco microorganisms on the quality of different shapes of tobacco. Specifically, Bacillus subtilis B1 and Cytobacillus oceanisediminis C4 with high protease, amylase, and cellulase were isolated from the first-cured tobacco, followed by using them for solid-state fermentation of tobacco powder (TP) and tobacco leaves (TL). Results showed that strains B1 and C4 could significantly improve the sensory quality of TP, enabling it to outperform TL in overall texture and skeleton of tobacco products during cigarette smoking. Compared with the control, microbial fermentation could increase reducing sugar; regulate protein, starch, and cellulose, reduce nicotine, improve total aroma substances, and enable the surface of fermented TP and TL to be more loose, wrinkled, and porous. Microbial community analysis indicated that strains B1 and C4 could change the native structure of microbial community in TP and TL. LEfSe analysis revealed that the potential key biomarkers in TP and TL were Bacilli, Pseudonocardia, Pantoea, and Jeotgalicoccus, which may have cooperative effects with other microbial taxa in improving tobacco quality. This study provides a theoretical basis for improving tobacco fermentation process for better cigarettes quality.
PubMed: 38647749
DOI: 10.1186/s40643-023-00651-6 -
Environmental Microbiology Reports Apr 2024The cereal leaf beetle (CLB, Oulema melanopus) is one of the major cereal pests. The effect of insecticides belonging to different chemical classes, with different...
Cereal leaf beetle-associated bacteria enhance the survival of their host upon insecticide treatments and respond differently to insecticides with different modes of action.
The cereal leaf beetle (CLB, Oulema melanopus) is one of the major cereal pests. The effect of insecticides belonging to different chemical classes, with different mechanisms of action and the active substances' concentrations on the CLB bacterial microbiome, was investigated. Targeted metagenomic analysis of the V3-V4 regions of the 16S ribosomal gene was used to determine the composition of the CLB bacterial microbiome. Each of the insecticides caused a decrease in the abundance of bacteria of the genus Pantoea, and an increase in the abundance of bacteria of the genus Stenotrophomonas, Acinetobacter, compared to untreated insects. After cypermethrin application, a decrease in the relative abundance of bacteria of the genus Pseudomonas was noted. The dominant bacterial genera in cypermethrin-treated larvae were Lactococcus, Pantoea, while in insects exposed to chlorpyrifos or flonicamid it was Pseudomonas. Insecticide-treated larvae were characterized, on average, by higher biodiversity and richness of bacterial genera, compared to untreated insects. The depletion of CLB-associated bacteria resulted in a decrease in larval survival, especially after cypermethrin and chlorpyrifos treatments. The use of a metagenome-based functional prediction approach revealed a higher predicted function of bacterial acetyl-CoA C-acetyltransferase in flonicamid and chlorpyrifos-treated larvae and tRNA dimethyltransferase in cypermethrin-treated insects than in untreated insects.
Topics: Animals; Insecticides; Bacteria; Larva; Coleoptera; RNA, Ribosomal, 16S; Microbiota; Metagenomics; Pyrethrins; Chlorpyrifos; Pantoea
PubMed: 38644048
DOI: 10.1111/1758-2229.13247 -
Microbial Genomics Apr 2024(Enterobacterales: Erwiniaceae) are a group of cosmopolitan bacteria best known as the causative agents of various plant diseases. However, other species in this genus...
(Enterobacterales: Erwiniaceae) are a group of cosmopolitan bacteria best known as the causative agents of various plant diseases. However, other species in this genus have been found to play important roles as insect endosymbionts supplementing the diet of their hosts. Here, I describe Erwinia impunctatus (Erwimp) associated with the Highland midge (Diptera: Ceratopogonidae), an abundant biting pest in the Scottish Highlands. The genome of this new species was assembled using hybrid long and short read techniques, and a comparative analysis was undertaken with other members of the genus to understand its potential ecological niche and impact. Genome composition analysis revealed that Erwimp is similar to other endophytic and ectophytic species in the genus and is unlikely to be restricted to its insect host. Evidence for an additional plant host includes the presence of a carotenoid synthesis operon implicated as a virulence factor in plant-associated members in the sister genus . Unique features of Erwimp include several copies of intimin-like proteins which, along with signs of genome pseudogenization and a loss of certain metabolic pathways, suggests an element of host restriction seen elsewhere in the genus. Furthermore, a screening of individuals over two field seasons revealed the absence of the bacteria in during the second year indicating this microbe-insect interaction is likely to be transient. These data suggest that may have an important role to play beyond a biting nuisance, as an insect vector transmitting Erwimp alongside any conferred impacts to surrounding biota.
Topics: Humans; Animals; Ceratopogonidae; Erwinia; Genomics; Insect Vectors; Ecosystem
PubMed: 38630610
DOI: 10.1099/mgen.0.001242 -
FEMS Microbiology Ecology May 2024Coffee leaf rust, caused by the fungus Hemileia vastatrix, has become a major concern for coffee-producing countries. Additionally, there has been an increase in the...
Coffee leaf rust, caused by the fungus Hemileia vastatrix, has become a major concern for coffee-producing countries. Additionally, there has been an increase in the resistance of certain races of the fungus to fungicides and breeding cultivars, making producers use alternative control methods. In this work, we transplanted the leaf surface microbiota of rust-resistant coffee species (Coffea racemosa and Coffea stenophylla) to Coffea arabica and tested whether the new microbiota would be able to minimize the damage caused by H. vastatrix. It was seen that the transplant was successful in controlling rust, especially from C. stenophylla, but the protection depended on the concentration of the microbiota. Certain fungi, such as Acrocalymma, Bipolaris, Didymella, Nigrospora, Setophaeosphaeria, Simplicillium, Stagonospora and Torula, and bacteria, such as Chryseobacterium, Sphingobium and especially Enterobacter, had their populations increased and this may be related to the antagonism seen against H. vastatrix. Interestingly, the relative population of bacteria from genera Pantoea, Methylobacterium and Sphingomonas decreased after transplantation, suggesting a positive interaction between them and H. vastatrix development. Our findings may help to better understand the role of the microbiota in coffee leaf rust, as well as help to optimize the development of biocontrol agents.
Topics: Coffea; Plant Diseases; Plant Leaves; Basidiomycota; Microbiota; Disease Resistance; Bacteria; Fungi
PubMed: 38599638
DOI: 10.1093/femsec/fiae049