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Frontiers in Microbiology 2023Endophytes are colonizers of healthy plants and they normally exhibit biocontrol activities, such as reducing the occurrence of plant diseases and promoting plant...
Whole-genome analysis revealed the growth-promoting and biological control mechanism of the endophytic bacterial strain Q2H2, with strong antagonistic activity in potato plants.
INTRODUCTION
Endophytes are colonizers of healthy plants and they normally exhibit biocontrol activities, such as reducing the occurrence of plant diseases and promoting plant growth. The endophytic bacterium Q2H2 (Q2H2) was isolated from the roots of potato plants and was found to have an antagonistic effect on pathogenic fungi.
METHODS
Q2H2 was identified by morphological observations, physiological and biochemical identification, and 16S rRNA gene sequence analysis. Genes related to the anti-fungal and growth-promoting effects were analyzed using whole-genome sequencing and comparative genomic analysis. Finally, we analyzed the growth-promoting and biocontrol activities of Q2H2 in potato plants using pot experiments.
RESULTS
Antagonism and non-volatile substance plate tests showed that Q2H2 had strong antagonism against , , , , and . The plate test showed that Q2H2 had the ability to produce proteases, cellulases, β-1,3-glucanase, dissolved organic phosphate, siderophores, indole-3-acetic acid (IAA), ammonia and fix nitrogen. The suitable growth ranges of Q2H2 under different forms of abiotic stress were pH 5-9, a temperature of 15-30°C, and a salt concentration of 1-5%. Though whole-genome sequencing, we obtained sequencing data of approximately 4.16 MB encompassed 4,102 coding sequences. We predicted 10 secondary metabolite gene clusters related to antagonism and growth promotion, including five known products surfactin, bacillaene, fengycin, bacilysin, bacillibactin, and subtilosin A. Average nucleotide identity and comparative genomic analyses revealed that Q2H2 was . Through gene function annotation, we analyzed genes related to antagonism and plant growth promotion in the Q2H2 genome. These included genes involved in phosphate metabolism (, , , and ), nitrogen fixation (, , , and ), ammonia production (, , , and ), siderophore production (, , , and ), IAA production (), biofilm formation (, , and ), and volatile compound production (, , , and ), and genes encoding hydrolases (, , , , , and ). The potato pot test showed that Q2H2 had an obvious growth-promoting effect on potato roots and better control of wilt than carbendazim.
CONCLUSION
These findings suggest that the strain-specific genes identified in bacterial endophytes may reveal important antagonistic and plant growth-promoting mechanisms.
PubMed: 38235428
DOI: 10.3389/fmicb.2023.1287921 -
International Journal of Analytical... 2024Method validation is an essential technique for ensuring the reliability and accuracy of an analytical method. This study aimed to optimize and validate a fast,...
Method Validation and Measurement Uncertainty Estimation for Determination of Multiclass Pesticide Residues in Tomato by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).
Method validation is an essential technique for ensuring the reliability and accuracy of an analytical method. This study aimed to optimize and validate a fast, reliable, and accurate method for quantitatively determining pesticide residues of diverse chemical classes in the tomato matrix. Various method performance characteristics were tested and compared with predefined criteria. Twenty-six different pesticides of diverse chemical classes were selected based on their use in tomato cultivation and the availability of reference materials. The pesticide residues in tomato samples were extracted with the QuEChERS technique with some modifications, followed by injection into an LC-MS/MS system operating in an optimized method. The validated method demonstrated reasonable specificity, as there were no interferences from matrix components at the retention times of pesticides. The calibration curves for all pesticides exhibited excellent linearities, with correlation coefficients exceeding 0.99. No significant matrix effect was observed for all pesticides in tomatoes, as the values fell within the range of ±20%. All pesticides were quantified successfully at a concentration of 5 g/kg except for carbaryl, with an average recovery of more than 70% and a relative standard deviation of less than 20%. Similarly, measurement uncertainties were also estimated based on the validation data, and the values were found below the default limit of 50%. Subsequently, the validated method was applied to analyze 52 locally collected tomato samples. Study findings revealed that only four of the studied pesticides were detected in these samples, and their concentrations were below the maximum residue limits (500 g/kg each for carbendazim, imidacloprid, and metalaxyl) established for tomatoes by the Government of Nepal and the Codex Alimentarius Commission.
PubMed: 38235055
DOI: 10.1155/2024/3846392 -
Materials (Basel, Switzerland) Dec 2023In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect pesticides with high sensitivity and...
In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect pesticides with high sensitivity and selectivity. Current research presents a novel approach utilising platinum nanoparticles (NPs) and reduced graphene oxide deposited on a glassy carbon electrode (Pt-rGO/GCE) for direct electrochemical measurement of carbendazim (CBZ). A straightforward one-step electrodeposition process was applied to prepare the Pt-rGO sensing platform. The incorporation of conductive rGO nanosheets along with distinctive structured Pt NPs significantly enhanced the effective electrode surface area and electron transfer of CBZ. Additionally, when exposed to 50 µM CBZ, Pt-rGO/GCE exhibited a higher current response compared to the bare electrode. Further investigations were performed to analyse and optimise the experimental parameters that could influence pesticide detection. Under the optimised conditions of pH 7 and 5 min of accumulation time, the Pt-rGO/GCE sensor showed a linear concentration detection range from 0.1 µM to 50 µM, with a detection limit of 3.46 nM. The fabricated sensor was successfully employed for CBZ detection in milk and tap water with 98.88% and 98.57% recovery, respectively. The fabricated sensor showed higher sensitivity and reproducibility, thus indicating the potential of this technology in the development of reliable sensors for the detection of CBZ or similar pesticides in forthcoming applications.
PubMed: 38138764
DOI: 10.3390/ma16247622 -
MycoKeys 2023Vetiver grass () has received extensive attention in recent years due to its diverse applications in soil and water conservation, heavy metal remediation, as well as...
Vetiver grass () has received extensive attention in recent years due to its diverse applications in soil and water conservation, heavy metal remediation, as well as essential oil and phenolic acids extraction. In 2019, the emergence of tar spot disease on was documented in Zhanjiang, Guangdong Province, China. Initially, the disease manifested as black ascomata embedded within leaf tissue, either scattered or clustered on leaf surfaces. Subsequently, these ascomata became surrounded by fisheye lesions, characterised by brown, elliptical, necrotic haloes, which eventually coalesced, resulting in leaf withering. Koch's postulates demonstrated that the fungus isolated from these lesions was the causal agent. Microscopic examination showed that the pathogen morphologically belonged to . The phylogenetic tree inferred from the combined ITS, LSU, and sequences revealed the three isolates including GDMCC 3.683, LNU-196 and LNU-197 to be a novel species of . Combining the results of phylogenetic, pathogenicity and morphological analyses, we propose a new species named as the causal agent of in southern China. The optimum growth temperature for was determined to be 30 °C. The in vitro fungicide sensitivity of was determined using a mycelial growth assay. Four demethylation-inhibiting (DMI) fungicides, including difenoconazole, flusilazole, propiconazole and tebuconazole and one methyl benzimidazole carbamate (MBC) fungicide, carbendazim, were effective against , with mean 50% effective concentration (EC) values of 0.077, 0.011, 0.004, 0.024 and 0.007 μg/ml, respectively. These findings provide essential references for the precise diagnosis and effective management of .
PubMed: 38098976
DOI: 10.3897/mycokeys.100.112128 -
Environment International Dec 2023The intensive use of pesticides in the North China Plain (NCP) has resulted in widespread contamination of pesticides in the local atmosphere, posing risks to air...
The intensive use of pesticides in the North China Plain (NCP) has resulted in widespread contamination of pesticides in the local atmosphere, posing risks to air quality and human health. However, the occurrence and distribution of atmospheric pesticides in the NCP as well as their risk assessment have not been well investigated. In this study, 300 monthly samples were collected using passive air samplers with polyurethane foam at ten rural sites with different crop systems in Quzhou county, the NCP, from June 2021 to May 2022. The pesticides were quantified using mass-spectrometric techniques. Our results revealed that chlorpyrifos, carbendazim, and atrazine were the most frequently found pesticides in the air samples, with detection frequencies of ≥ 87 % across the samples. The average concentrations of atmospheric pesticides during spring (7.47 pg m) and summer (16.05 pg m) were significantly higher than those during autumn (2.04 pg m) and winter (1.71 pg m), attributable to the intensified application of pesticides during the warmer seasons. Additionally, cash crop sites exhibited higher concentrations (10.26 pg m) of atmospheric pesticides compared to grain crop (5.59 pg m) and greenhouse sites (3.81 pg m), primarily due to more frequent pesticides spraying events in cash crop fields. These findings indicate a distinct spatial-temporal distribution pattern of atmospheric pesticides influenced by both seasons and crop systems. Furthermore, the model-based inhalation risk assessment indicates that inhalation exposure to atmospheric pesticides is unlikely to pose a significant public concern.
Topics: Humans; Pesticides; Air Pollutants; Environmental Monitoring; Air Pollution; China; Seasons
PubMed: 38006771
DOI: 10.1016/j.envint.2023.108342 -
Toxics Nov 2023The world population is experiencing colossal growth and thus demand for food, leading to an increase in the use of pesticides. Persistent pesticide contamination, such...
The world population is experiencing colossal growth and thus demand for food, leading to an increase in the use of pesticides. Persistent pesticide contamination, such as carbendazim, remains a pressing environmental concern, with potentially long-term impacts on aquatic ecosystems. In the present study, was exposed to carbendazim (5 µg L) for 12 generations, with the aim of assessing gene transcription alterations induced by carbendazim (using a custom microarray). The results showed that carbendazim caused changes in genes involved in the response to stress, DNA replication/repair, neurotransmission, ATP production, and lipid and carbohydrate metabolism at concentrations already found in the environment. These outcomes support the results of previous studies, in which carbendazim induced genotoxic effects and reproduction impairment (increasing the number of aborted eggs with the decreasing number of neonates produced). The exposure of daphnids to carbendazim did not cause a stable change in gene transcription between generations, with more genes being differentially expressed in the F0 generation than in the F12 generation. This could show some possible daphnid acclimation after 12 generations and is aligned with previous multigenerational studies where few ecotoxicological effects at the individual and populational levels and other subcellular level effects (e.g., biochemical biomarkers) were found.
PubMed: 37999570
DOI: 10.3390/toxics11110918 -
PloS One 2023Effective management of fungicide application programs requires monitoring the profile of resistant populations of Botrytis cinerea, given its high-risk nature. This...
Effective management of fungicide application programs requires monitoring the profile of resistant populations of Botrytis cinerea, given its high-risk nature. This research aimed to examine the sensitivity of 200 B. cinerea isolates collected from different plant species and regions across Iran towards thiophanate-methyl and carbendazim fungicides. To distinguish between susceptible and resistant isolates, the discriminatory dose assay was employed, followed by the selection of representative isolates from each group for EC50 analysis. To identify potential modifications in codon 198 of the β-tubulin gene in B. cinerea resistant isolates, the researchers employed the PCR-RFLP diagnostic method. More than two-thirds of the isolates exhibited a varying degree of resistance to MBC fungicides, even in farms where the application of these fungicides had not taken place in recent years. After treatment with the BsaI enzyme, the PCR product of sensitive isolates displayed two bands measuring 98 and 371 bp, while only one band of 469 bp was identified in resistant isolates. The study also evaluated whether resistance to fungicides could affect the pathogenicity and mycelial growth of the isolates. The findings showed no significant difference between the resistant and sensitive groups in terms of these factors, indicating that resistance does not come at a cost to the pathogen's fitness. Considering the high incidence of resistance and the absence of negative consequences on fitness, it is recommended to exercise caution in the employment of benzimidazole fungicides as part of B. cinerea management strategies.
Topics: Fungicides, Industrial; Iran; Incidence; Drug Resistance, Fungal; Plant Diseases; Botrytis; Benzimidazoles
PubMed: 37988349
DOI: 10.1371/journal.pone.0294530 -
Molecules (Basel, Switzerland) Oct 2023Herein, ZIF-67-derived Co and N-doped carbon (Co/NC) particle-modified multilayer MXene (MXene@Co/NC) was developed as remarkable electrode material for carbendazim...
Herein, ZIF-67-derived Co and N-doped carbon (Co/NC) particle-modified multilayer MXene (MXene@Co/NC) was developed as remarkable electrode material for carbendazim (CBZ) detection. MXene as a substrate provides an excellent conductive framework and plentiful accessibility sites. Co/NC particles embedding in MXene can not only prevent the interlayer stacking of MXene but also contribute a great deal of metal catalytic active sites and finally improve the adsorption and catalytic properties of the composite. Accordingly, the MXene@Co/NC electrode displays excellent electrocatalytic activity toward CBZ oxidation. Experimental parameters such as pH value, accumulation time, MXene@Co/NC modification volume and constituent materials' mass ratios were optimized. Under optimal conditions, the as-prepared sensor based on MXene@Co/NC holds a broad linearity range from 0.01 μM to 45.0 μM with a low limit of detection (LOD) of 3.3 nM (S/N = 3, S means the detection signal, while N represents the noise of the instrument). Moreover, the proposed sensor displays excellent anti-interference ability, superior reproducibility, excellent stability, and successfully achieves actual applications for CBZ detection in a lettuce sample.
PubMed: 37959766
DOI: 10.3390/molecules28217347 -
Journal of Fungi (Basel, Switzerland) Oct 2023The Fusarium head blight (FHB) caused by is one of the most important diseases threatening wheat production in China. However, the triazole sterol 14α-demethylation...
The Fusarium head blight (FHB) caused by is one of the most important diseases threatening wheat production in China. However, the triazole sterol 14α-demethylation inhibitor (DMI), prothioconazole, is known to exhibit high activity against . The current study indicated that three highly resistant laboratory mutants exhibited significantly ( < 0.05) altered growth and sporulation, although contrary to expectation, only one of the mutants exhibited reduced growth and sporulation, while the other two exhibited significant ( < 0.05) increases. Despite this, pathogenicity tests revealed that all of the mutants exhibited significantly ( < 0.05) reduced pathogenicity, indicating a substantial cost to fitness. Sequence analysis of the prothioconazole target protein, CYP51, of which has three homologues (FgCYP51A, FgCYP51B, and FgCYP51C), identified three mutations in the FgCYP51B sequence with a high likelihood of being associated with the observed resistance, as well as another three mutations in the FgCYP51B sequence, and two in the FgCYP51A sequence that are worthy of further investigation. Two of the prothioconazole-resistant mutants were also found to have several amino acid substitutions in their FgCYP51C sequences, and it was interesting to note that these two mutants exhibited significantly ( < 0.05) reduced pathogenicity compared to the other mutant. Expression analysis revealed that prothioconazole treatment (0.1 μg/mL) resulted in altered expression of all the target genes, and that expression was also altered in the prothioconazole-resistant mutants compared to their wild-type parental isolates. Meanwhile, no evidence was found of any cross-resistance between prothioconazole and other commonly used fungicides, including carbendazim, pyraclostrobin, and fluazinam, as well as the triazole tebuconazole and the imidazole DMI prochloraz. Taken together, these results not only provide new insight into potential resistance mechanism in , and the biological characteristics associated with them, but also convincing evidence that prothioconazole can offer effective control of FHB.
PubMed: 37888257
DOI: 10.3390/jof9101001 -
Heliyon Oct 2023The presence of pesticides in our environment is a consequence of intensive industrial and civilizational development, necessitating the search for effective and safe...
The presence of pesticides in our environment is a consequence of intensive industrial and civilizational development, necessitating the search for effective and safe methods to remove them. We suggest utilizing zeolite X and a zeolite-carbon composite, obtained through the chemical transformation of fly ash, as pesticide sorbents. To increase the sorption efficiency of 2,4-dichlorophenoxyacetic acid (2,4-D), 2-methyl-4-chlorophenoxyacetic acid (MCPA), carbendazim, and simazine, we functionalized the zeolite materials with cationic (hexadecyltrimethylammonium) and nonionic (Triton X-100) surfactants. We used transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric/differential thermal analysis (TG/DTA) and point of zero charge (pHpzc) analysis to characterize the functionalized sorbent materials. Our results indicate that cationic surfactants significantly enhance the adsorption of 2,4-D and MCPA. In contrast, carbendazim and simazine exhibit maximum sorption on the unmodified zeolite-carbon composite. The sorption mechanism is intricate, with physical sorption predominating, primarily due to electrostatic interactions between the protonated binding sites of the adsorbents and the negatively charged pesticide molecules. Regeneration tests demonstrated that ethanol is the most effective in regenerating zeolite-carbon composite with adsorbed MCPA and 2,4-D, while thermal regeneration was not possible. Adsorbents with simazine and carbendazim can be regenerated using both thermal and ethanol methods, but the thermal regeneration of zeolite with adsorbed simazine is more efficient. Utilizing functionalized zeolite materials obtained from industrial waste, such as fly ash, could provide an efficient way to remove pesticides from the environment.
PubMed: 37842606
DOI: 10.1016/j.heliyon.2023.e20572