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MSystems Feb 2024Root-associated microorganisms play an important role in plant health, such as plant growth-promoting rhizobacteria (PGPR) from the and genera. Although bacterial...
Root-associated microorganisms play an important role in plant health, such as plant growth-promoting rhizobacteria (PGPR) from the and genera. Although bacterial consortia including these two genera would represent a promising avenue to efficient biofertilizer formulation, we observed that root colonization is decreased by the presence of and . To determine if can adapt to the inhibitory effect of on roots, we conducted adaptative laboratory evolution experiments with in mono-association or co-cultured with on tomato plant roots. Evolved isolates with various colony morphology and stronger colonization capacity of both tomato plant and roots emerged rapidly from the two evolution experiments. Certain evolved isolates also had better fitness on the root in the presence of other species. In all independent lineages, whole-genome resequencing revealed non-synonymous mutations in genes or encoding regulators involved in repressing biofilm development, suggesting their involvement in enhanced root colonization. These findings provide insights into the molecular mechanisms underlying adaptation to root colonization and highlight the potential of directed evolution to enhance the beneficial traits of PGPR.IMPORTANCEIn this study, we aimed to enhance the abilities of the plant-beneficial bacterium to colonize plant roots in the presence of competing bacteria. To achieve this, we conducted adaptive laboratory experiments, allowing to evolve in a defined environment. We successfully obtained strains of that were more effective at colonizing plant roots than the ancestor strain. To identify the genetic changes driving this improvement, we sequenced the genomes of these evolved strains. Interestingly, mutations that facilitated the formation of robust biofilms on roots were predominant. Many of these evolved isolates also displayed the remarkable ability to outcompete species. Our research sheds light on the mutational paths selected in to thrive in root environments and offers exciting prospects for improving beneficial traits in plant growth-promoting microorganisms. Ultimately, this could pave the way for the development of more effective biofertilizers and sustainable agricultural practices.
Topics: Bacillus subtilis; Bacillus; Biofilms; Arabidopsis; Pseudomonas fluorescens
PubMed: 38206029
DOI: 10.1128/msystems.00843-23 -
ACS Omega Dec 2023Considering the importance of rice ( L.) for global food and its significant production in Brazil, strategies for its sustainable production are focused on technologies...
Considering the importance of rice ( L.) for global food and its significant production in Brazil, strategies for its sustainable production are focused on technologies to increase productivity and decrease the use of chemical nitrogen fertilizers. An alternative for this is the use of plant growth-promoting bacteria that have proven to be efficient for increasing production and nutrient promotion in cereals. This study reports the use of coinoculation with and to inoculate irrigated rice through seed treatment (ST) with inoculant and seed inoculation in planting furrow technology (PFT) in four field experiments. The inoculation technologies increased rice yields in the presence of + and with a reduction in mineral N (30 kg of N ha), equal to or greater when nitrogen fertilizer was present alone. Our results demonstrate that coinoculation with (strain Ab-V6) and (strain CCTB03) increases the efficiency of N use from a mineral source in irrigated rice, with an increase of 37% in economic production (grains per unit of N applied), providing better agronomic performance of the crop.
PubMed: 38162741
DOI: 10.1021/acsomega.3c05339 -
Nanomaterials (Basel, Switzerland) Dec 2023This work studies the antimicrobial activity of benzyldimethyldodecyl ammonium chloride (BDMDAC)-coated microparticles with distinct morphological structures....
This work studies the antimicrobial activity of benzyldimethyldodecyl ammonium chloride (BDMDAC)-coated microparticles with distinct morphological structures. Functionalized microparticles were prepared by the layer-by-layer (LbL) self-assembly technique on hydroxyapatite (Hap), calcium carbonate (CaCO) and glass beads (GB) cores. All particles were characterized, before and after functionalization, by Fourier-Transform Infrared Spectroscopy (FTIR), Brunner-Emmett-Teller (BET) and Scanning Electron Microscopy (SEM) analyses. Antimicrobial activity was tested against planktonic . Planktonic bacteria were exposed to 100 mg/L, 200 mg/L and 400 mg/L of BDMDAC-coated microparticles for 240 min. This strategy promoted a complete bacteria reduction at 200 mg/L for Hap microparticles after 240 min. No release of biocide was detected through HPLC analyses during 2 weeks, suggesting that bacteria inactivation may be attributed to a contact killing mechanism.
PubMed: 38063763
DOI: 10.3390/nano13233067 -
Microbiology Spectrum Jan 2024Cheatgrass is one of North America's most problematic invasive species. Invasion by this annual grass alters ecosystem structure and function and has proven very...
Cheatgrass is one of North America's most problematic invasive species. Invasion by this annual grass alters ecosystem structure and function and has proven very challenging to remove with traditional approaches. Commercially available bioherbicides, like . D7, are applied with the goal of providing lasting control from a single application. However, experimental results suggest that this bioherbicide has limited efficacy under field conditions. Potential explanations for variable efficacy include a failure of this bioherbicide to establish in the soil microbiome. However, to our knowledge, no data exist to support or refute this hypothesis. Here, we use a deep-sequencing approach to better understand the effects of this bioherbicide on the soil microbiome and screen for at 18 months post-application.
Topics: Bromus; Ecosystem; Pseudomonas fluorescens; Soil; Poaceae
PubMed: 38051051
DOI: 10.1128/spectrum.01771-23 -
BioRxiv : the Preprint Server For... Nov 2023Biofilms of the sulfate reducing bacterium (SRB) Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to...
Biofilms of the sulfate reducing bacterium (SRB) Hildenborough (DvH) can facilitate metal corrosion in various industrial and environmental settings leading to substantial economic losses; however, the mechanisms of biofilm formation by DvH are not yet well-understood. Evidence suggests that a large adhesin, DvhA, may be contributing to biofilm formation in DvH. The gene and its neighbors encode proteins that resemble the Lap system, which regulates biofilm formation by , including a LapG-like protease DvhG and effector protein DvhD, which has key differences from the previously described LapD. By expressing the Lap-like adhesion components of DvH in , our data support the model that the N-terminal fragment of the large adhesin DvhA serves as an adhesin "retention module" and is the target of the DvhG/DvhD regulatory module, thereby controlling cell-surface location of the adhesin. By heterologously expressing the DvhG/DvhD-like proteins in a background lacking native regulation (ΔΔ) we also show that cell surface regulation of the adhesin is dependent upon the intracellular levels of c-di-GMP. This study provides insight into the key players responsible for biofilm formation by DvH, thereby expanding our understanding of Lap-like systems.
PubMed: 38045380
DOI: 10.1101/2023.11.22.568322 -
Heliyon Nov 2023The present study was carried out in a pot experiment to examine the bioefficacy of three biocontrol agents, viz., , , and , either alone or in consortium, on plant...
The present study was carried out in a pot experiment to examine the bioefficacy of three biocontrol agents, viz., , , and , either alone or in consortium, on plant growth promotion and activation of defense responses in potato against the early blight pathogen . The results demonstrate significant enhancement in growth parameters in plants bioprimed with the triple-microbe consortium compared to other treatments. In potato, the disease incidence percentage was significantly reduced in plants treated with the triple-microbe consortium compared to untreated control plants challenged with . Potato tubers treated with the consortium and challenged with pathogen showed significant activation of defense-related enzymes such as peroxidase (PO) at 96 h after pathogen inoculation (hapi) while, both polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) at 72 hapi, compared to the individual and dual microbial consortia-treated plants. The expression of antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT) and the accumulation of pathogenesis-related proteins such as chitinase and β-1,3-glucanase were observed to be highest at 72 hapi in the triple microbe consortium as compared to other treatments. HPLC analysis revealed significant induction in polyphenolic compounds in triple-consortium bioprimed plants compared to the control at 72 hapi. Histochemical analysis of hydrogen peroxide (HO) clearly showed maximum accumulation of HO in pathogen-inoculated control plants, while the lowest was observed in triple-microbe consortium at 72 hapi. The findings of this study suggest that biopriming with a microbial consortium improved plant growth and triggered defense responses against through the induction of systemic resistance via modulation of the phenylpropanoid pathway and antioxidative network.
PubMed: 38045140
DOI: 10.1016/j.heliyon.2023.e22148 -
Frontiers in Microbiology 2023CFBP2392 has been recognized as a potential biocontrol agent due to its ability to suppress damping-off and root rot disease. This isolate has antibacterial activity...
CFBP2392 has been recognized as a potential biocontrol agent due to its ability to suppress damping-off and root rot disease. This isolate has antibacterial activity as many other strains from the complex. In this work, the antibacterial and antifungal activity of the strain were explored. Dual culture assays evidenced the antifungal activity of the strain against different phytopathogens: sp., , , and . Purification of an antifungal fraction was performed by preparative HPLC from the chemical extraction of growth media. The fraction showed altered growth and ultrastructure. Transmission electron microscopy revealed the purified compound hypertrophied mitochondria, membranous vesicles, and a higher number of vacuoles in cytoplasm. In addition, co-cultivation of CFBP2392 with resulted in an enlarged and deformed cell wall. To gain genomic insights on this inhibition, the complete genome of CFBP2392 was obtained with Oxford Nanopore technology. Different biosynthetic gene clusters (BGCs) involved in specialized metabolites production including a lokisin-like and a koreenceine-like cluster were identified. In accordance with the putative BGCs identified, sequence phylogeny analysis of the MacB transporter in the lokisin-like cluster further supports the similarity with other transporters from the amphisin family. Our results give insights into the cellular effects of the purified microbial metabolite in ultrastructure and provide a genomic background to further explore the specialized metabolite potential.
PubMed: 38033591
DOI: 10.3389/fmicb.2023.1286926 -
Sensors & Diagnostics Sep 2023Rapid and precise identification of infectious microorganisms is important across a range of applications where microbial contamination can cause serious issues ranging...
Rapid and precise identification of infectious microorganisms is important across a range of applications where microbial contamination can cause serious issues ranging from microbial resistance to corrosion. In this paper a screen-printed, polymeric β-cyclodextrin (β-CD) modified electrode, affording nanocavities for inclusion of the analytes, is shown as a disposable sensor capable of identifying bacteria by their metabolites. Three bacterial species were tested: two from the genus, () and (), and (), a member of the family, . On biofilm formation each species gave distinct, reproducible, redox fingerprints with a detection limit of 4 × 10 M. Square wave adsorptive stripping voltammetry (SWAdSV) was used for detection. Scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques were used to characterize the morphology and electrical conductivity of the modified electrode. In comparison to the bare screen-printed electrode, the modified electrode showed a considerably higher performance and offered an excellent sensitivity along with a relatively fast analysis time.
PubMed: 38014404
DOI: 10.1039/d3sd00074e -
International Journal of Molecular... Nov 2023The ability of the MF3 protein from to protect plants by inducing their resistance to pathogenic fungi, bacteria, and viruses is well confirmed both in greenhouses and...
The ability of the MF3 protein from to protect plants by inducing their resistance to pathogenic fungi, bacteria, and viruses is well confirmed both in greenhouses and in the field; however, the molecular basis of this phenomenon remains unexplored. To find a relationship between the primary (and spatial) structure of the protein and its target activity, we analyzed the inducing activity of a set of mutants generated by alanine scanning and an alpha-helix deletion (ahD) in the part of the MF3 molecule previously identified by our group as a 29-amino-acid peptide working as the inducer on its own. Testing the mutants' inducing activity using the "tobacco-tobacco mosaic virus" pathosystem revealed that some of them showed an almost threefold (V60A and V62A) or twofold (G51A, L58A, ahD) reduction in inducing activity compared to the wild-type MF3 type. Interestingly, these mutations demonstrated close proximity in the homology model, probably contributing to MF3 reception in a host plant.
Topics: Bacterial Proteins; Plants; Tobacco Mosaic Virus; Fungi; Plant Diseases; Nicotiana; Plant Viruses
PubMed: 38003563
DOI: 10.3390/ijms242216374