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Plants (Basel, Switzerland) Apr 2024Soil-borne spp. have been extensively studied for their biocontrol activities against pathogens and growth promotion ability in plants. However, the beneficial effect...
Soil-borne spp. have been extensively studied for their biocontrol activities against pathogens and growth promotion ability in plants. However, the beneficial effect of on inducing resistance against insect herbivores has been underexplored. Among diverse species, consistent with previous reports, we showed that root colonization by triggered induced systemic resistance (ISR) to the leaf-infecting hemibiotrophic fungal pathogens . Whether induces ISR to insect pests has not been tested before. In this study, we investigated whether affects jasmonic acid (JA) biosynthesis and defense against fall armyworm (FAW) and western corn rootworm (WCR). Unexpectedly, the results showed that colonization of maize seedlings grown in autoclaved soil suppressed wound-induced production of JA, resulting in reduced resistance to FAW. Similarly, the bacterial endophyte 30-84 was found to suppress systemic resistance to FAW due to reduced JA. Further comparative analyses of the systemic effects of these endophytes when applied in sterile or non-sterile field soil showed that both and 30-84 triggered ISR against C. in both soil conditions, but only suppressed JA production and resistance to FAW in sterile soil, while no significant impact was observed when applied in non-sterile soil. In contrast to the effect on FAW defense, colonization of maize roots suppressed WCR larvae survival and weight gain. This is the first report suggesting the potential role of as a biocontrol agent against WCR.
PubMed: 38732455
DOI: 10.3390/plants13091240 -
Microorganisms Jan 2021To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and...
To guarantee the supply of critical elements in the future, the development of new technologies is essential. Siderophores have high potential in the recovery and recycling of valuable metals due to their metal-chelating properties. Using the Chrome azurol S assay, 75 bacterial strains were screened to obtain a high-yield siderophore with the ability to complex valuable critical metal ions. The siderophore production of the four selected strains 3E, DSM 50083, EPS, and B7g was optimized, resulting in significantly increased siderophore production of and . Produced siderophore amounts and velocities were highly dependent on the carbon source. The genomes of and were sequenced. Bioinformatical analyses revealed the occurrence of an achromobactin and a pyoverdine gene cluster in , a heterobactin and a requichelin gene cluster in , and a desferrioxamine gene cluster in Finally, the results of the previous metal-binding screening were validated by a proof-of-concept development for the recovery of metal ions from aqueous solutions utilizing C columns functionalized with siderophores. We demonstrated the recovery of the critical metal ions V(III), Ga(III), and In(III) from mixed metal solutions with immobilized siderophores of and
PubMed: 33466508
DOI: 10.3390/microorganisms9010111 -
Molecules (Basel, Switzerland) Aug 2021In this work, we propose the utilization of scCO to impregnate ibuprofen into the mcl-PHA matrix produced by subs. (DSM 19603). The biopolymer has adhesive properties,...
In this work, we propose the utilization of scCO to impregnate ibuprofen into the mcl-PHA matrix produced by subs. (DSM 19603). The biopolymer has adhesive properties, is biocompatible and has a melting temperature of 45 °C. Several conditions, namely, pressure (15 and 20 MPa) and impregnation time (30 min, 1 h and 3 h) were tested. The highest ibuprofen content (90.8 ± 6.5 mg of ibuprofen/g) was obtained at 20 MPa and 40 °C, for 1 h, with an impregnation rate of 89 mg/(g·h). The processed mcl-PHA samples suffered a plasticization, as shown by the decrease of 6.5 °C in the T, at 20 MPa. The polymer's crystallinity was also affected concomitantly with the matrices' ibuprofen content. For all the impregnation conditions tested the release of ibuprofen from the biopolymer followed a type II release profile. This study has demonstrated that the mcl-PHA produced by has a great potential for the development of novel topical drug delivery systems.
Topics: Adhesiveness; Carbon Dioxide; Drug Carriers; Drug Liberation; Ibuprofen; Polyhydroxyalkanoates; Temperature
PubMed: 34443357
DOI: 10.3390/molecules26164772 -
Microbiological Research Aug 2020Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant...
Genome analysis of plant growth-promoting rhizobacterium Pseudomonas chlororaphis subsp. aurantiaca JD37 and insights from comparasion of genomics with three Pseudomonas strains.
Pseudomonas chlororaphis subsp. aurantiaca strain JD37 is a plant growth-promoting rhizobacterium (PGPR), which has important biotechnological features such as plant growth promotion, rhizosphere colonization and biocontrol activities. In present study, the genome sequence of JD37 was obtained and comparative genomic analysis were performed to explore unique features of the JD37 genome and its relationship with other Pseudomonas PGPR: P. chlororaphis PA23, P. protegens Pf-5 and P. aeruginosa M18. JD37 possessed a single circular chromosome of 6,702,062 bp in length with an average GC content of 62.75 %. No plasmid was detected in JD37. A total of 5003 functional proteins of JD37 were predicted according to the clusters of orthologous groups (COGs) database. The JD37 genome consisted of various genes involved in plant growth promotion, biocontrol activities and defense responses. Genes involved in the rhizosphere colonization and motility were also found in the genome of JD37, suggesting the common plant growth-promoting traits in PGPR. The identified resistance genes (e.g. those related to metal resistance, antibiotics, and osmotic and temperature-shock) and secondary metabolite biosynthesis revealed the pathways for metabolites it produced. Data presented in present study further provided valuable information on its molecular genetics and adaptive capacity in the rhizosphere niche.
Topics: Disease Resistance; Drug Resistance, Microbial; Gene Ontology; Genes, Bacterial; Genome, Bacterial; Genomics; Phylogeny; Plant Development; Pseudomonas; Rhizosphere; Secondary Metabolism
PubMed: 32402945
DOI: 10.1016/j.micres.2020.126483 -
Frontiers in Microbiology 2023The spectral distribution of light (different wavelength) has recently been identified as an important factor in the dynamics and function of leaf-associated microbes....
BACKGROUND
The spectral distribution of light (different wavelength) has recently been identified as an important factor in the dynamics and function of leaf-associated microbes. This study investigated the impact of different wavelength on three commercial biocontrol agents (BCA): (BA), (PC), and (SG).
METHODS
The impact of light exposure on sole carbon source utilization, biofilm formation, and biosurfactant production by the selected BCA was studied using phenotypic microarray (PM) including 190 sole carbon sources (OmniLog®, PM panels 1 and 2). The BCA were exposed to five monochromatic light conditions (420, 460, 530, 630, and 660 nm) and darkness during incubation, at an intensity of 50 μmol m s.
RESULTS
Light exposure together with specific carbon source increased respiration in all three BCA. Different wavelengths of light influenced sole carbon utilization for the different BCA, with BA and PC showing increased respiration when exposed to wavelengths within the blue spectrum (420 and 460 nm) while respiration of selected carbon sources by SG increased in the presence of red light (630 and 660 nm). Only one carbon source (capric acid) generated biosurfactant production in all three BCA. A combination of specific wavelength of light and sole carbon source increased biofilm formation in all three BCA. BA showed significantly higher biofilm formation when exposed to blue (460 nm) and green (530 nm) light and propagated in D-sucrose, D-fructose, and dulcitol. PC showed higher biofilm formation when exposed to blue light. Biofilm formation by SG increased when exposed to red light (630 nm) and propagated in citraconic acid.
CONCLUSION
To increase attachment and success in BCA introduced into the phyllosphere, a suitable combination of light quality and nutrient conditions could be used.
PubMed: 36819051
DOI: 10.3389/fmicb.2023.1087639 -
Applied and Environmental Microbiology Feb 2020Bacterial rhizosphere colonization is critical for phytobeneficial rhizobacteria such as phenazine-producing spp. To better understand this colonization process,...
Bacterial rhizosphere colonization is critical for phytobeneficial rhizobacteria such as phenazine-producing spp. To better understand this colonization process, potential metabolic and genomic determinants required for rhizosphere colonization were identified using a collection of 60 phenazine-producing strains isolated from multiple plant species and representative of the worldwide diversity. and (potato) were used as host plants. Bacterial rhizosphere colonization was measured by quantitative PCR using a newly designed primer pair and TaqMan probe targeting a conserved region of the phenazine biosynthetic operon. The metabolic abilities of the strains were assessed on 758 substrates using Biolog phenotype microarray technology. These data, along with available genomic sequences for all strains, were analyzed in light of rhizosphere colonization. Strains belonging to the subgroup colonized the rhizospheres of both plants more efficiently than strains belonging to the subgroup. Metabolic results indicated that the ability to use amines and amino acids was associated with an increase in rhizosphere colonization capability in and/or in The presence of multiple genetic determinants in the genomes of the different strains involved in catabolic pathways and plant-microbe and microbe-microbe interactions correlated with increased or decreased rhizosphere colonization capabilities in both plants. These results suggest that the metabolic and genomic traits found in different phenazine-producing strains reflect their rhizosphere competence in and Interestingly, most of these traits are associated with similar rhizosphere colonizing capabilities in both plant species. Rhizosphere colonization is crucial for plant growth promotion and biocontrol by antibiotic-producing spp. This colonization process relies on different bacterial determinants which partly remain to be uncovered. In this study, we combined a metabolic and a genomic approach to decipher new rhizosphere colonization determinants which could improve our understanding of this process in spp. Using 60 distinct strains of phenazine-producing spp., we show that rhizosphere colonization abilities correlated with both metabolic and genomic traits when these bacteria were inoculated on two distant plants, and Key metabolic and genomic determinants presumably required for efficient colonization of both plant species were identified. Upon further validation, these targets could lead to the development of simple screening tests to rapidly identify efficient rhizosphere colonizers.
Topics: Arabidopsis; Genome, Bacterial; Phenazines; Pseudomonas; Rhizosphere; Solanum tuberosum
PubMed: 31811040
DOI: 10.1128/AEM.02443-19 -
Frontiers in Microbiology 2020LuxR solos are common in plant-associated bacteria and increasingly recognized for playing important roles in plant-microbe interkingdom signaling. Unlike the LuxR-type...
LuxR solos are common in plant-associated bacteria and increasingly recognized for playing important roles in plant-microbe interkingdom signaling. Unlike the LuxR-type transcriptional regulators of prototype LuxR/LuxI quorum sensing systems, solos do not have a LuxI-type autoinducer synthase gene associated with them. LuxR solos in plant-pathogenic bacteria are important for virulence and in plant endosymbionts contribute to symbiosis. In the present study, we characterized an atypical LuxR solo, PcsR2, in the biological control species 30-84 that is highly conserved among sequenced s strains. Unlike most LuxR solos in the plant-associated bacteria characterized to date, is not associated with a proline iminopeptidase gene and the protein has an atypical N-terminal binding domain. We created a deletion mutant and used quantitative RT-PCR to show that the expression of and genes in the operon immediately downstream was upregulated ∼10-fold when the wild type strain was grown on wheat roots compared to planktonic culture. PcsR2 was involved in upregulation. Using a GFP transcriptional reporter, we found that expression of responded specifically to root-derived substrates as compared to leaf-derived substrates but not to endogenous AHLs. Compared to the wild type, the mutant was impaired in the ability to utilize root carbon and nitrogen sources in wheat root macerate and to colonize wheat roots. Phenazine production and most biofilm traits previously shown to be correlated with phenazine production also were diminished in the mutant. Gene expression of several of the proteins in the phenazine regulatory network including PhzR, Pip (phenazine inducing protein) and RpeA/RpeB were reduced in the mutant, and overexpression of these genes restored phenazine production in the mutant to wild-type levels, indicating PcsR2 affects the activity of the these regulatory genes upstream of RpeA/RpeB via an undetermined mechanism. Our results indicate PcsR2 upregulates the expression of the adjacent operon in response to unknown wheat root-derived signals and belongs to a novel subfamily of LuxR-type transcriptional regulators found in sequenced strains.
PubMed: 33244313
DOI: 10.3389/fmicb.2020.560124 -
Microorganisms Sep 2021The bacterial pathogen causes the destructive fruit blotch (BFB) on cucurbit plants. YL-1 is a bacterial strain isolated from Mississippi soil and its genome harbors...
The bacterial pathogen causes the destructive fruit blotch (BFB) on cucurbit plants. YL-1 is a bacterial strain isolated from Mississippi soil and its genome harbors some antimicrobial-related gene clusters, such as phenazine, pyrrolnitrin, and pyoverdine. Here, we evaluated the antimicrobial activity of strain YL-1 as compared with its deficient mutants of antimicrobial-related genes, which were obtained using a based site-specific mutagenesis strategy. We found that only phenazine-deficient mutants Δ and Δ almost lost the inhibitory effects against in LB plates compared with the wild-type strain YL-1, and that the main antibacterial compound produced by strain YL-1 in LB medium was phenazine-1-carboxylic acid (PCA) based on the liquid chromatography-mass spectrometry (LC-MS) analysis. Gene expression analyses revealed that PCA enhanced the accumulation of reactive oxygen species (ROS) and increased the activity of catalase (CAT) in . The inhibition effect of PCA against was lowered by adding exogenous CAT. PCA significantly upregulated the transcript level of from 6 to 10 h, which encodes CAT that helps to protect the bacteria against oxidative stress. Collectively, the findings of this research suggest PCA is one of the key antimicrobial metabolites of bacterial strain YL-1, a promising biocontrol agent for disease management of BFB of cucurbit plants.
PubMed: 34683333
DOI: 10.3390/microorganisms9102012 -
3 Biotech Feb 2021In this study, nine strains of and , and two isolates of sp: At1RP4 and RS-1, were characterized for the in-vitro production of secondary metabolites in LB, DMB, and...
UNLABELLED
In this study, nine strains of and , and two isolates of sp: At1RP4 and RS-1, were characterized for the in-vitro production of secondary metabolites in LB, DMB, and King's B media, and of the genes responsible for the production of antagonistic metabolites. Based on 16S rRNA gene sequence, isolates At1RP4 and RS-1 were identified as strains of and . Five phenazine derivatives comprising phenazine, phenazine-1-carboxylic acid (PCA), 2-hydroxyphenazine-1-carboxylic acid (2-OH-Phz-1-COOH), phenazine-1,6-dicarboxylic acid (Phz-1,6-di-COOH), and 2-hydroxyphenazine (2-OH-Phz) were produced by all strains in all three culture media including DMB, King's B and LB. However, 2,8-dihydroxyphenazine, 6-methylphenazine-1-carboxylic acid, pyrrolnitrin, and the -dialkylaromatic acids, were produced by the and strains. In addition, all strains produced 2-acetamidophenol, pyochelin, and diketopiperazine derivatives in variable amounts in all three culture media used. Highest levels of quorum-sensing signal molecules including PQS, 2-Octyl-3-hydroxy-4(1H)-quinolone, and hexahydro-quinoxaline-1,4-dioxide were recorded for At1RP4. Moreover, all strains produced volatile hydrogen cyanide (0.95-6.68 µg/L) and the phytohormone indole-3-acetic acid (0.42-13.9 µM). Production of extracellular lipase and protease was recorded in all pseudomonads, whereas, cellulase production and phosphate solubilization were variable. Genes for hydrogen cyanide and phenazine-1-carboxylic acid were detected in all eleven strains while the gene for pyrrolnitrin biosynthesis was amplified in and strains. Comparative metabolomic analysis provided detailed insights about the strain-specific metabolites in pseudomonads, and their pseudo-relative quantification in different bacterial growth media to be used as single-strain biofertilizer and biocontrol inoculums.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s13205-020-02585-8.
PubMed: 33489669
DOI: 10.1007/s13205-020-02585-8 -
Frontiers in Microbiology 2022f. sp. () tropical race 4 (TR4) is threatening banana production because of its increasing spread. Biological control approaches have been widely studied and...
f. sp. () tropical race 4 (TR4) is threatening banana production because of its increasing spread. Biological control approaches have been widely studied and constitute interesting complementary measures to integrated disease management strategies. They have been based mainly on the use of single biological control agents (BCAs). In this study, we moved a step forward by designing a synthetic microbial community (SynCom) for the control of Fusarium wilt of banana (FWB). Ninety-six isolates of spp., spp., spp., and spp. were obtained from the banana rhizosphere and selected for the antagonism against TR4. In pot experiments, a large community such as SynCom 1.0 (44 isolates with moderate to high antagonistic activity) or a small one such as SynCom 1.1 (seven highly effective isolates) provided similar disease control (35% symptom severity reduction). An study of the interactions among SynCom 1.1 isolates and between them and revealed that beneficial microorganisms not only antagonized the pathogen but also some of the SynCom constituents. Furthermore, defended itself by antagonizing the beneficial microbes. We also demonstrated that fusaric acid, known as one of the secondary metabolites of species, might be involved in such an interaction. With this knowledge, SynCom 1.2 was then designed with three isolates: subsp. PS5, BN8.2, and T2C1.4. A non-simultaneous soil application of these isolates (to diminish cross-inhibition) delayed FWB progress over time, with significant reductions in incidence and severity. SynCom 1.2 also performed better than two commercial BCAs, BioPak and T-Gro. Eventually, SynCom 1.2 isolates were characterized for several biocontrol traits and their genome was sequenced. Our data showed that assembling a SynCom for biocontrol is not an easy task. The mere mixtures of antagonists (e.g., SynCom 1.0 and 1.1) might provide effective biocontrol, but an accurate investigation of the interactions among beneficial microorganisms is needed to improve the results (e.g., SynCom 1.2). SynCom 1.2 is a valuable tool to be further developed for the biological control of FWB.
PubMed: 35992653
DOI: 10.3389/fmicb.2022.967885