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Plant Disease Sep 2023Center rot of onion is caused by a complex of plant pathogenic species, which can lead to significant yield losses in the field and during storage. Conventional growers...
Center rot of onion is caused by a complex of plant pathogenic species, which can lead to significant yield losses in the field and during storage. Conventional growers use foliar protectants such as a mixture of copper bactericides and an ethylene-bis-dithiocarbamate (EBDC) fungicide to manage the disease; however, organic growers have limited management options besides copper-protectants. Biocontrol agents (BCAs) provide an alternative; however, their efficacy could be compromised due in part to their inability to colonize the foliage. We hypothesized that pretreatment with peroxide (OxiDate 2.0: a.i., hydrogen peroxide and peroxyacetic acid) enhances the colonizing ability of the subsequently applied BCAs, leading to effective center rot management. Field trials were conducted in 2020 and 2021 to assess the efficacy of peroxide, BCAs (Serenade ASO: and BlightBan: ), and an insecticide program (tank mix of spinosad and neem oil) to manage center rot. We observed no significant difference in foliar area under the disease progress curve (AUDPC) between the peroxide pretreated plots and only -treated plots in 2020 and 2021. Peroxide pretreatment before application significantly reduced the foliar AUDPC as compared with the stand-alone treatment in 2020; however, no such difference was observed in 2021. Similarly, peroxide pretreatment before either of the BCAs did not seem to reduce the incidence of bulb rot as compared with the stand-alone BCA treatment in any of the trials (2020 and 2021). Additionally, our foliar microbiome study showed comparatively higher retention on peroxide pretreated onion foliage; however, at the end of the growing season, was drastically reduced and was virtually nonexistent (<0.002% of the total reads). Overall, the pretreatment with peroxide had a limited effect in improving the foliar colonizing ability of BCAs and consequently a limited effect in managing center rot.
Topics: Pantoea; Copper; Plant Diseases; Fungicides, Industrial; Peroxides
PubMed: 36774574
DOI: 10.1094/PDIS-11-22-2710-RE -
Scientific Reports Oct 2023Mosquito control in Egypt depends on applying chemical synthetic pesticides that impact negatively on human health and the environment as well as the development of...
Mosquito control in Egypt depends on applying chemical synthetic pesticides that impact negatively on human health and the environment as well as the development of antibiotic and chemical resistance. This study aims to control the 3rd and 4th instars of Culex pipiens larvae using four bacterial strains. According to Phenotypic and molecular identification, the four isolates were identified as Bacillus subtilis MICUL D2023, Serratia marcescens MICUL A2023, Streptomyces albus LARVICID, and Pseudomonas fluorescens MICUL B2023. All strains were deposited in GenBank under accession numbers OQ764791, OQ729954, OQ726575, and OQ891356, respectively. Larvicidal activity of all microbial strain metabolites against a field strain of C. pipiens explored low LC results and reached its lowest values on the 3rd day with values of 6.40%, 38.4%, and 46.33% for P. fluorescens, S. albus, and S. marcescens, respectively. In addition, metabolites of P. fluorescence were more toxic than those of S. albus, followed by S. marcescens. B. subtilis shows no larvicidal effect on both field and lab mosquito strains. Microscopic alterations of 3rd and 4th instars showed toxic effects on different body parts (thorax, midgut, and anal gills), including losing external hairs, abdominal breakage, and larvae shrinkage, as well as different histological malformations in the digestive tract, midgut, and cortex. GC-MS analysis detected 51, 30, and 32 different active compounds from S. albus, S. marcescens, and P. fluorescens, respectively. GC detected 1, 2-BENZEA2:A52NEDICARBOXYLIC ACID, 2-Cyclohexene-1-carboxylic-acid-5-2-butenyl-methyl ester, and 3 octadecahydro2R3S4Z9Z-11R-12S from S. albus, S. marcesens, and P. fluorescens, respectively. Total protein, Total carbohydrate, and Acetylcholine esterase activity indicated significantly low levels on the 3rd day. All strain metabolites were safe against HSF cell lines. The docking results confirmed the role of the produced metabolites as larvicidal agents and Acetylcholine esterase inhibition. Such a problem need more studies on applying more and more natural pesticides.
Topics: Animals; Humans; Culex; Egypt; Molecular Docking Simulation; Acetylcholine; Insecticides; Larva; Pesticides; Serratia marcescens; Esterases; Culicidae
PubMed: 37821509
DOI: 10.1038/s41598-023-44279-0 -
Plants (Basel, Switzerland) Mar 2024Milpa is an agroecological production system based on the polyculture of plant species, with corn featuring as a central component. Traditionally, the milpa system does...
Milpa is an agroecological production system based on the polyculture of plant species, with corn featuring as a central component. Traditionally, the milpa system does not require the application of chemicals, and so pest attacks and poor growth in poor soils can have adverse effects on its production. Therefore, the application of bioinoculants could be a strategy for improving crop growth and health; however, the effect of external inoculant agents on the endemic microbiota associated with corn has not been extensively studied. Here, the objective of this work was to fertilize a maize crop under a milpa agrosystem with the PGPR UM270, evaluating its impact on the diversity of the rhizosphere (rhizobiome) and root endophytic (root endobiome) microbiomes of maize plants. The endobiome of maize roots was evaluated by 16S rRNA and internal transcribed spacer region (ITS) sequencing, and the rhizobiome was assessed by metagenomic sequencing upon inoculation with the strain UM270. The results showed that UM270 inoculation of the rhizosphere of UM270 did not increase alpha diversity in either the monoculture or milpa, but it did alter the endophytic microbiome of maize plant roots by stimulating the presence of bacterial operational taxonomic units (OTUs) of the genera and (in a monoculture), whereas, in the milpa system, the PGPR stimulated greater endophytic diversity and the presence of genera such as , , and N-fixing rhizobia genera, including , , and . No clear association was found between fungal diversity and the presence of strain UM270, but beneficial fungi, such as and , were detected in the Milpa system. In addition, network analysis revealed unique interactions with species such as sp., , and , which could potentially play beneficial roles in the plant. Finally, the UM270 strain does not seem to have a strong impact on the microbial diversity of the rhizosphere, but it does have a strong impact on some functions, such as trehalose synthesis, ammonium assimilation, and polyamine metabolism. The inoculation of UM270 biofertilizer in maize plants modifies the rhizo- and endophytic microbiomes with a high potential for stimulating plant growth and health in agroecological crop models.
PubMed: 38611483
DOI: 10.3390/plants13070954 -
Applied Microbiology and Biotechnology Nov 2023
PubMed: 37792061
DOI: 10.1007/s00253-023-12800-0 -
International Journal of Food... Feb 2024Pseudomonas fluorescens is a spoilage bacterium in food that has the ability to maintain growth and reproduction in high-salt environments. It acts as a defence...
Pseudomonas fluorescens is a spoilage bacterium in food that has the ability to maintain growth and reproduction in high-salt environments. It acts as a defence mechanism through the exclusion of ions and the formation of biofilms. Hence, disrupting this defence mechanism may be a good way to control food spoilage. In this study, a specific flavonoid small molecule baicalin was found, which was able to dismantle the defence mechanism of the bacteria at a lower concentration (400 μM) of treatment. In synergy with salt, baicalin showed a significant inhibitory effect on the growth, c-di-gmp synthetics and biofilm formation of Pseudomonas fluorescens Pf08. Through transcriptomics, we also found that baicalein interfered with bacterial transport and polysaccharide production functions. Through molecular docking and QPCR, we found that baicalin is able to binding with the RpoS protein through hydrogen bonding and thus interfere with its function.
Topics: Pseudomonas fluorescens; Molecular Docking Simulation; Biofilms
PubMed: 38181519
DOI: 10.1016/j.ijfoodmicro.2023.110553 -
World Journal of Clinical Cases Apr 2024The clinical incidence of spinal infection is gradually increasing, and its onset is insidious, easily leading to missed diagnosis and misdiagnosis, which may lead to...
BACKGROUND
The clinical incidence of spinal infection is gradually increasing, and its onset is insidious, easily leading to missed diagnosis and misdiagnosis, which may lead to serious complications such as nervous system dysfunction, spinal instability and/or deformity, and cause a huge burden on society and families. Early identification of the causative agent and precision medicine will greatly reduce the suffering of patients. At present, the main pathogenic bacteria that cause spinal infection are , Streptococcus, Pneumococcus, , and Klebsiella. There are no reports of spinal infection caused by .
CASE SUMMARY
We report a 32-year-old female patient with spinal infection. She presented with flank pain, initially thought to be bone metastases or bone tuberculosis, and had a family background of tumors. Her clinical features and changes in imaging and laboratory tests led to the suspicion of thoracic spine infection. Histopathology of the lesion showed inflammation, tissue culture of the lesion was negative several times, and the possible pathogen - was found after gene sequencing of the lesion. The patient recovered completely after a full course of antibiotic treatment.
CONCLUSION
This report increases the range of pathogens involved in spinal infections, highlights the unique advantages of gene sequencing technology in difficult-to-diagnose diseases, and validates conservative treatment with a full course of antibiotics for spinal infections without complications.
PubMed: 38680271
DOI: 10.12998/wjcc.v12.i12.2099 -
Folia Microbiologica May 2024There is an increasing demand for bioinoculants based on plant growth-promoting rhizobacteria (PGPR) for use in agricultural ecosystems. However, there are still...
There is an increasing demand for bioinoculants based on plant growth-promoting rhizobacteria (PGPR) for use in agricultural ecosystems. However, there are still concerns and limited data on their reproducibility in different soil types and their effects on endemic rhizosphere communities. Therefore, this study explored the effects of inoculating the PGPR, Pseudomonas fluorescens strain UM270, on maize growth (Zea mays L.) and its associated rhizosphere bacteriome by sequencing the 16S ribosomal genes under greenhouse conditions. The results showed that inoculation with PGPR P. fluorescens UM270 improved shoot and root dry weights, chlorophyll concentration, and total biomass in the three soil types evaluated (clay, sandy-loam, and loam) compared to those of the controls. Bacterial community analysis of the three soil types revealed that maize plants inoculated with the UM270 strain showed a significant increase in Proteobacteria and Acidobacteria populations, whereas Actinobacteria and Bacteroidetes decreased. Shannon, Pielou, and Faith alpha-biodiversity indices did not reveal significant differences between treatments. Beta diversity revealed a bacterial community differential structure in each soil type, with some variation among treatments. Finally, some bacterial groups were found to co-occur and co-exclude with respect to UM270 inoculation. Considered together, these results show that PGPR P. fluorescens UM270 increases maize plant growth and has an important effect on the resident rhizobacterial communities of each soil type, making it a potential agricultural biofertilizer.
PubMed: 38748205
DOI: 10.1007/s12223-024-01171-2 -
Journal of Applied Microbiology May 2024We aimed to develop an effective bacterial combination that can combat Fusarium oxysporum infection in watermelon using in vitro and pot experiments.
AIMS
We aimed to develop an effective bacterial combination that can combat Fusarium oxysporum infection in watermelon using in vitro and pot experiments.
METHODS AND RESULTS
In total, 53 strains of Bacillus and 4 strains of Pseudomonas were screened. Pseudomonas strains P3 and P4 and Bacillus strains XY-2-3, XY-13, and GJ-1-15 exhibited good antagonistic effects against F. oxysporum. P3 and P4 were identified as Pseudomonas chlororaphis and Pseudomonas fluorescens, respectively. XY-2-3 and GJ-1-15 were identified as B. velezensis, and XY-13 was identified as Bacillus amyloliquefaciens. The three Bacillus strains were antifungal, promoted the growth of watermelon seedlings and had genes to synthesize antagonistic metabolites such as bacilysin, surfactin, yndj, fengycin, iturin, and bacillomycin D. Combinations of Bacillus and Pseudomonas strains, namely, XY-2-3 + P4, GJ-1-15 + P4, XY-13 + P3, and XY-13 + P4, exhibited a good compatibility. These four combinations exhibited antagonistic effects against 11 pathogenic fungi, including various strains of F. oxysporum, Fusarium solani, and Rhizoctonia. Inoculation of these bacterial combinations significantly reduced the incidence of Fusarium wilt in watermelon, promoted plant growth, and improved soil nutrient availability. XY-13 + P4 was the most effective combination against Fusarium wilt in watermelon with the inhibition rate of 78.17%. The number of leaves; aboveground fresh and dry weights; chlorophyll, soil total nitrogen, and soil available phosphorus content increased by 26.8%, 72.12%, 60.47%, 16.97%, 20.16%, and 16.50%, respectively, after XY-13 + P4 inoculation compared with the uninoculated control. Moreover, total root length, root surface area, and root volume of watermelon seedlings were the highest after XY-13 + P3 inoculation, exhibiting increases by 265.83%, 316.79%, and 390.99%, respectively, compared with the uninoculated control.
CONCLUSIONS
XY-13 + P4 was the best bacterial combination for controlling Fusarium wilt in watermelon, promoting the growth of watermelon seedlings, and improving soil nutrient availability.
Topics: Fusarium; Citrullus; Plant Diseases; Bacillus; Disease Resistance; Pseudomonas; Antibiosis; Pseudomonas fluorescens; Seedlings; Antifungal Agents
PubMed: 38632051
DOI: 10.1093/jambio/lxae074 -
Microorganisms Jul 2023Tomatoes are one of the most important crops worldwide and also play a central role in the human diet. Microbial consortia are microorganism associations, often employed...
Tomatoes are one of the most important crops worldwide and also play a central role in the human diet. Microbial consortia are microorganism associations, often employed as bioinoculants, that can interact with the native rhizosphere microbiota. The aim of this study was to evaluate the impact of a bacterial-based biostimulant ( and (PSBA) in combination, or not, with a commercial inoculum Micomix (, , , , ) (MYC) on the native rhizosphere communities and on tomato production. The trial was carried out using in an open field as follows: control full NPK (CFD), control reduced NPK (CRD), MYC, PSBA, PSBA + MYC. Bacterial population in the different samples were characterized using a next generation sequencing approach. The bioinocula effect on the native rhizosphere microbiota resulted in significant variation both in alpha and beta diversity and in a specific signature associated with the presence of biostimulants, especially in the presence of co-inoculation (PSBA + MYC). In particular, the high initial biodiversity shifts in the community composition occurred and consisted in the increase in the abundance of genera correlated to the soil acidification and in an enhanced density of nitrogen-fixing microbes. The results also highlighted the well-known rhizosphere effect.
PubMed: 37630451
DOI: 10.3390/microorganisms11081891 -
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