Stimulation of estrogen receptor-alpha by hydroxyanilide fungicide, fenhexamid promotes lipid accumulation in 3 T3-L1 adipocyte.

Fenhexamid are fungicides that act against plant pathogens by inhibiting sterol biosynthesis. Nonetheless, it can trigger endocrine disruption and promote breast cancer cell growth. In a recent study, we investigated the mechanism underlying the lipid accumulation induced by fenhexamid hydroxyanilide fungicides in 3 T3-L1 adipocytes. To examine the estrogen receptor alpha (ERα)-agonistic effect, ER transactivation assay using the ERα-HeLa-9903 cell line was applied, and fenhexamid-induced ERα agonist effect was confirmed. Further confirmation that ERα-dependent lipid accumulation occurred was provided by treating 3 T3-L1 adipocytes with Methyl-piperidino-pyrazole hydrate (MPP), an ERα-selective antagonist. Fenhexamid mimicked the actions of ERα agonists and impacted lipid metabolism, and its mechanism involves upregulation of the expression of transcription factors that facilitate adipogenesis and lipogenesis. Additionally, it stimulated the expression of peroxisome proliferator-activated receptor (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), fatty acid synthase (FAS), and sterol regulatory element-binding protein 1 (SREBP1) and significantly elevated the expression of fatty acid-binding protein 4 (FABP4). In contrast, in combination with an ERα-selective antagonist, fenhexamid suppressed the expression of adipogenic/lipogenic transcription factors. These results suggest that fenhexamid affects the endocrine system and leads to lipid accumulation by interfering with processes influenced by ERα activation.

Discovery and Development of Luvangetin from Zanthoxylum avicennae as a New Fungicide Candidate for Fusarium verticillioides.

Pathogenic fungi pose a significant threat to crop yields and human healthy, and the subsequent fungicide resistance has greatly aggravated these agricultural and medical challenges. Hence, the development of new fungicides with higher efficiency and greater environmental friendliness is urgently required. In this study, luvangetin, isolated and identified from the root of Zanthoxylum avicennae, exhibited wide-spectrum antifungal activity in vivo and in vitro. Integrated omics and in vitro and in vivo transcriptional analyses revealed that luvangetin inhibited GAL4-like Zn(II)2Cys6 transcriptional factor-mediated transcription, particularly the FvFUM21-mediated FUM cluster gene expression, and decreased the biosynthesis of fumonisins inFusarium verticillioides. Moreover, luvangetin binds to the double-stranded DNA helix in vitro in the groove mode. We isolated and identified luvangetin, a natural metabolite from a traditional Chinese edible medicinal plant and uncovered its multipathogen resistance mechanism. This study is the first to reveal the mechanism underlying the antifungal activity of luvangetin and provides a promising direction for the future use of plant-derived natural products to prevent and control plant and animal pathogenic fungi.

Transgenerational effects of triazole fungicides on gene expression and egg compounds in non-exposed offspring: A case study using Red-Legged Partridges (Alectoris rufa).

Triazole fungicides are widely used to treat cereal seeds before sowing. Granivorous birds like the Red-legged Partridge (Alectoris rufa) have high exposure risk because they ingest treated seeds that remain on the field surface. As triazole fungicides can act as endocrine disruptors, affecting sterol synthesis and reproduction in birds several months after exposure, we hypothesized that these effects could also impact subsequent generations of exposed birds. To test this hypothesis, we exposed adult partridges (F0) to seeds treated at commercial doses with four different formulations containing triazoles as active ingredients (flutriafol, prothioconazole, tebuconazole, and a mixture of the latter two), simulating field exposure during late autumn sowing. During the subsequent reproductive season, two to four months after exposure, we examined compound allocation of steroid hormones, cholesterol, vitamins, and carotenoids in eggs laid by exposed birds (F1), as well as the expression of genes encoding enzymes involved in sterol biosynthesis in one-day-old chicks of this F1. One year later, F1 animals were paired again to investigate the expression of the same genes in the F2 chicks. We found changes in the expression of some genes for all treatments and both generations. Additionally, we observed an increase in estrone levels in eggs from partridges treated with flutriafol compared to controls, a decrease in tocopherol levels in partridges exposed to the mixture of tebuconazole and prothioconazole, and an increase in retinol levels in partridges exposed to prothioconazole. Despite sample size limitations, this study provides novel insights into the mechanisms of action of the previously observed effects of triazole fungicide-treated seeds on avian reproduction with evidence that the effects can persist beyond the exposure windows, affecting unexposed offspring of partridges fed with treated seeds. The results highlight the importance of considering long-term chronic effects when assessing pesticide risks to wild birds.

Environmental Evaluation on Toxicity, Toxic Mechanism, and Hydrolysis Behavior of Potential Acethydrazide Fungicide Candidates.

The evaluation of toxicity and environmental behavior of bioactive lead molecules is helpful in providing theoretical support for the development of agrochemicals, in line with the sustainable development of the ecological environment. In previous work, some acethydrazide structures have been demonstrated to exhibit excellent and broad-spectrum fungicidal activity; however, its environmental compatibility needs to be further elucidated if it is to be identified as a potential fungicide. In this project, the toxicity of fungicidal acethydrazide lead compounds F51, F58, F72, and F75 to zebrafish was determined at 10 µg mL-1 and 1 µg mL-1. Subsequently, the toxic mechanism of compound F58 was preliminarily explored by histologic section and TEM observations, which revealed that the gallbladder volume of common carp treated with compound F58 increased, accompanied by a deepened bile color, damaged plasma membrane, and atrophied mitochondria in gallbladder cells. Approximately, F58-treated hepatocytes exhibited cytoplasmic heterogeneity, with partial cellular vacuolation and mitochondrial membrane rupture. Metabolomics analysis further indicated that differential metabolites were enriched in the bile formation-associated steroid biosynthesis, primary bile acid biosynthesis, and taurine and hypotaurine metabolism pathways, as well as in the membrane function-related glycerophospholipid metabolism, linolenic acid metabolism, α-linolenic acid metabolism, and arachidonic acid metabolism pathways, suggesting that the acethydrazide F58 may have acute liver toxicity to common carp. Finally, the hydrolysis dynamics of F58 was investigated, with the obtained half-life of 5.82 days. The above results provide important guiding significance for the development of new green fungicides.

Mycoremediation of the novel fungicide ametoctradin by different agricultural soils and accelerated degradation utilizing selected fungal strains.

Accelerating safety assessments for novel agrochemicals is imperative, advocating for in vitro setups to present pesticide biodegradation by soil microbiota before field studies. This approach enables metabolic profile generation in a controlled laboratory environment eliminating extrinsic factors. In the current study, ten different soil samples were utilized to check their capability to degrade Ametoctradin by their microbiota. Furthermore, five different fungal strains (Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Lasiodiplodia theobromae, and Penicillium chrysogenum) were utilized to degrade Ametoctradin in aqueous media. A degradation pathway was established using the metabolic patterns created during the biodegradation of Ametoctradin. In contrast to 47% degradation (T1/2 of 34 days) when Ametoctradin was left in the soil samples, the fungal strain Aspergillus fumigatus demonstrated 71% degradation of parent Ametoctradin with a half-life (T1/2) of 16 days. In conclusion, soil rich in microorganisms effectively cleans Ametoctradin-contaminated areas while Fungi have also been shown to be an effective, affordable, and promising way to remove Ametoctradin from the environment.

Antifungal potential of lipopeptides produced by the Bacillus siamensis Sh420 strain against Fusarium graminearum.

Biological control is a more sustainable and environmentally friendly alternative to chemical fungicides for controlling Fusarium spp. infestations. In this work, Bacillus siamensis Sh420 isolated from wheat rhizosphere showed a high antifungal activity against Fusarium graminearum as a secure substitute for fungicides. Sh420 was identified as B. siamensis using phenotypic evaluation and 16S rDNA gene sequence analysis. An in vitro antagonistic study showed that Sh420's lipopeptide (LP) extract exhibited strong antifungal properties and effectively combated F. graminearum. Meanwhile, lipopeptides have the ability to decrease ergosterol content, which has an impact on the overall structure and stability of the plasma membrane. The PCR-based screening revealed the presence of antifungal LP biosynthetic genes in this strain's genomic DNA. In the crude LP extract of Sh420, we were able to discover several LPs such as bacillomycin, iturins, fengycin, and surfactins using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Microscopic investigations (fluorescent/transmission electron microscopy) revealed deformities and alterations in the morphology of the phytopathogen upon interaction with LPs. Sh420 LPs have been shown in grape tests to be effective against F. graminearum infection and to stimulate antioxidant activity in fruits by avoiding rust and gray lesions. The overall findings of this study highlight the potential of Sh420 lipopeptides as an effective biological control agent against F. graminearum infestations.IMPORTANCEThis study addresses the potential of lipopeptide (LP) extracts obtained from the strain identified as Bacillus siamensis Sh420. This Sh420 isolate acts as a crucial player in providing a sustainable and environmentally friendly alternative to chemical fungicides for suppressing Fusarium graminearum phytopathogen. Moreover, these LPs can reduce ergosterol content in the phytopathogen influencing the overall structure and stability of its plasma membrane. PCR screening provided confirmation regarding the existence of genes responsible for biosynthesizing antifungal LPs in the genomic DNA of Sh420. Several antibiotic lipopeptide compounds were identified from this bacterial crude extract using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Microscopic investigations revealed deformities and alterations in the morphology of F. graminearum upon interaction with LPs. Furthermore, studies on fruit demonstrated the efficacy of Sh420 LPs in mitigating F. graminearum infection and stimulating antioxidant activity in fruits, preventing rust and gray lesions.

Meptyldinocap induces implantation failure by forcing cell cycle arrest, mitochondrial dysfunction, and endoplasmic reticulum stress in porcine trophectoderm and endometrial luminal epithelial cells.

Meptyldinocap is a dinitrophenol fungicide used to control powdery mildew. Although other dinitrophenol pesticides have been found to exhibit reproductive toxicity, studies of meptyldinocaps are scarce. This study investigated the adverse effects of meptyldinocap on porcine trophectoderm (pTr) and porcine endometrial luminal epithelial (pLE) cells, which play crucial roles in implantation. We confirmed that meptyldinocap decreased cell viability, induced apoptosis, and inhibited proliferation by decreasing proliferation-related gene expression and inducing changes in the cell cycle. Furthermore, meptyldinocap treatment caused mitochondrial dysfunction, endoplasmic reticulum stress, and disruption of calcium homeostasis. Moreover, it induces alterations in mitogen-activated protein kinase signaling cascades and reduces the migration ability, leading to implantation failure. Our findings suggest that meptyldinocap reduces the cellular functions of pTr and pLE cells, which are important for the implantation process, and interferes with interactions between the two cell lines, potentially leading to implantation failure. We also propose a mechanism by which the understudied fungicide meptyldinocap exerts its cytotoxicity.

Cardiac and neurobehavioral impairments in three phylogenetically distant aquatic model organisms exposed to environmentally relevant concentrations of boscalid.

Boscalid (2-Chloro-N-(4'-chlorobiphenyl-2-yl) nicotinamide), a pyridine carboxamide fungicide, is an inhibitor of the complex II of the respiration chain in fungal mitochondria. As boscalid is only moderately toxic for aquatic organisms (LC50 > 1-10 mg/L), current environmental levels of this compound in aquatic ecosystems, in the range of ng/L-µg/L, are considered safe for aquatic organisms. In this study, we have exposed zebrafish (Danio rerio), Japanese medaka (Oryzias latipes) and Daphnia magna to a range of concentrations of boscalid (1-1000 µg/L) for 24 h, and the effects on heart rate (HR), basal locomotor activity (BLA), visual motor response (VMR), startle response (SR), and habituation (HB) to a series of vibrational or light stimuli have been evaluated. Moreover, changes in the profile of the main neurotransmitters have been determined. Boscalid altered HR in a concentration-dependent manner, leading to a positive or negative chronotropic effect in fish and D. magna, respectively. While boscalid decreased BLA and increased VMR in Daphnia, these behaviors were not altered in fish. For SR and HB, the response was more species- and concentration-specific, with Daphnia exhibiting the highest sensitivity. At the neurotransmission level, boscalid exposure decreased the levels of L-aspartic acid in fish larvae and increased the levels of dopaminergic metabolites in D. magna. Our study demonstrates that exposure to environmental levels of boscalid alters cardiac activity, impairs ecologically relevant behaviors, and leads to changes in different neurotransmitter systems in phylogenetically distinct vertebrate and invertebrate models. Thus, the results presented emphasize the need to review the current regulation of this fungicide.

Vitamin E alleviates pyraclostrobin-induced toxicity in zebrafish (Danio rerio) and its potential mechanisms.

Strobilurin fungicides (SFs) are commonly used in agriculture worldwide and frequently detected in aquatic environments. High toxicity of SFs to aquatic organisms has caused great concerns. To explore whether vitamin E (VE) can relieve the toxicity caused by pyraclostrobin (PY), zebrafish were exposed to PY with or without VE supplementation. When co-exposure with VE (20 µM), the 96 h-LC50 values of PY to zebrafish embryos, adult, and the 24 h-LC50 value of PY to larvae increased from 43.94, 58.36 and 38.16 µg/L to 64.72, 108.62 and 72.78 µg/L, respectively, indicating that VE significantly decreased the toxicity of PY to zebrafish at different life stages. In addition, VE alleviated the deformity symptoms (pericardial edema and brain damage), reduced speed and movement distance, and decreased heart rate caused by 40 µg/L PY in zebrafish larvae. Co-exposure of PY with VE significantly reduced PY-caused larval oxidative stress and immunotoxicity via increasing the activities of superoxide dismutase, catalase and level of glutathione, as well as reducing the malondialdehyde production and the expression levels of Nrf2, Ucp2, IL-8, IFN and CXCL-C1C. Meanwhile, the expression levels of gria4a and cacng4b genes, which were inhibited by PY, were significantly up-regulated after co-exposure of PY with VE. Moreover, co-exposure with VE significantly reversed the increased mitochondrial DNA copies and reduced ATP content caused by PY in larvae, but had no effect on the expression of cox4i1l and activity of complex III that reduced by PY, suggesting VE can partially improve PY-induced mitochondrial dysfunction. In conclusion, the potential mechanisms of VE alleviating PY-induced toxicity may be ascribed to decreasing the oxidative stress level, restoring the functions of heart and nervous system, and improving the immunity and mitochondrial function in zebrafish.

Effects of single and combined exposure of virgin or aged polyethylene microplastics and penthiopyrad on zebrafish (Danio rerio).

The interaction between pesticides and microplastics (MPs) can lead to changes in their mode of action and biological toxicity, creating substantial uncertainty in risk assessments. Succinate dehydrogenase inhibitor (SDHI) fungicides, a common fungicide type, are widely used. However, little is known about how penthiopyrad (PTH), a member of the SDHI fungicide group, interacts with polyethylene microplastics (PE-MPs). This study primarily investigates the individual and combined effects of virgin or aged PE-MPs and penthiopyrad on zebrafish (Danio rerio), including acute toxicity, bioaccumulation, tissue pathology, enzyme activities, gut microbiota, and gene expression. Short-term exposure revealed that PE-MPs enhance the acute toxicity of penthiopyrad. Long-term exposure demonstrated that PE-MPs, to some extent, enhance the accumulation of penthiopyrad in zebrafish, leading to increased oxidative stress injury in their intestines by the 7th day. Furthermore, exposure to penthiopyrad and/or PE-MPs did not result in histopathological damage to intestinal tissue but altered the gut flora at the phylum level. Regarding gene transcription, penthiopyrad exposure significantly modified the expression of pro-inflammatory genes in the zebrafish gut, with these effects being mitigated when VPE or APE was introduced. These findings offer a novel perspective on environmental behavior and underscore the importance of assessing the combined toxicity of PE-MPs and fungicides on organisms.

Chlorothalonil as a potential endocrine disruptor in male zebrafish (Danio rerio): Impact on the hypothalamus-pituitary-gonad axis and sperm quality.

Chlorothalonil is a broad-spectrum organochlorine fungicide widely employed in agriculture to control fungal foliar diseases. This fungicide enters aquatic environments through the leaching process, leading to toxicity in non-target organisms. Organic contaminants can impact organism reproduction as they have the potential to interact with the neuroendocrine system. Although there are reports of toxic effects of chlorothalonil, information regarding its impact on reproduction is limited. The aim of the present study was to evaluate the influence of chlorothalonil on male reproductive physiology using the zebrafish (Danio rerio) as ecotoxicological model. Zebrafish were exposed for 7 days to two concentrations of chlorothalonil (0.1 and 10 µg/L) along with a control group (with DMSO - 0.001%). Gene expression of hypothalamus-pituitary-gonad axis components (gnrh2, gnrh3, lhr, fshr, star, hsd17b1, hsd17b3, and cyp19a1), as well as hepatic vitellogenin concentration were assessed. In sperm cells, reactive oxygen species (ROS) content, lipid peroxidation (LPO), mitochondrial functionality, and membrane integrity and fluidity were evaluated. Results indicate that exposure to the higher concentration of chlorothalonil led to a reduction in brain gnr2 expression. In gonads, mRNA levels of lhr, star, and hsd17b1 were decreased at both chlorothalonil concentrations tested. Similarly, hepatic vitellogenin concentration was reduced. Regarding sperm cells, a decreased ROS level was observed, without significant difference in LPO level. Additionally, a higher mitochondrial potential and lower membrane fluidity were observed in zebrafish exposed to chlorothalonil. These findings demonstrate that chlorothalonil acts as an endocrine disruptor, influencing reproductive control mechanisms, as evidenced by changes in expression of genes HPG axis, as well as hepatic vitellogenin concentration. Furthermore, our findings reveal that exposure to this contaminant may compromise the reproductive success of the species, as it affected sperm quality parameters.

Mitochondria-Associated Protein FgNdk1 Regulates the Development, Pathogenicity, and SDHI Fungicide Sensitivity of Fusarium graminearum by Interacting with Succinate Dehydrogenase.

Nucleoside diphosphate kinase (NDK) plays an important role in many cellular processes in all organisms. In this study, we functionally characterized a nucleoside diphosphate kinase (FgNdk1) in Fusarium graminearum, a causal agent of Fusarium head blight (FHB). FgNdk1 was involved in the generation of energy in the electron-transfer chain by interacting with succinate dehydrogenase (FgSdhA, FgSdhC1, and FgSdhC2). Deletion of FgNdk1 not only resulted in abnormal mitochondrial morphology, decreased ATP content, defective fungal development, and impairment in the formation of the toxisome but also led to the suppressed expression level of DON biosynthesis enzymes, decreased DON biosynthesis, and declined pathogenicity as well. Furthermore, deletion of FgNdk1 caused increasing transcriptional levels of FgSdhC1 and FgdhC2, in the presence of pydiflumetofen, related to the decreased sensitivity to SDHI fungicides. Overall, this study identified a new regulatory mechanism of FgNdk1 in the pathogenicity and SDHI fungicide sensitivity of Fusarium graminearum.

Potential anti-Pythium insidiosum therapeutics identified through screening of agricultural fungicides.

Pythiosis is a life-threatening infectious disease caused by the oomycete Pythium insidiosum. Clinical manifestations of pythiosis include an eye, blood vessel, skin, or gastrointestinal tract infection. Pythiosis has been increasingly reported worldwide, with an overall mortality rate of 28%. Radical surgery is required to save patients' lives due to the limited efficacy of antimicrobial drugs. Effective medical treatments are urgently needed for pythiosis. This study aims to find anti-P. insidiosum agents by screening 17 agricultural fungicides that inhibit plant-pathogenic oomycetes and validating their efficacy and safety. Cyazofamid outperformed other fungicides as it can potently inhibit genetically diverse P. insidiosum isolates while exhibiting minimal cellular toxicities. The calculated therapeutic scores determined that the concentration of cyazofamid causing significant cellular toxicities was eight times greater than the concentration of the drug effectively inhibiting P. insidiosum. Furthermore, other studies showed that cyazofamid exhibits low-to-moderate toxicities in animals. The mechanism of cyazofamid action is likely the inhibition of cytochrome b, an essential component in ATP synthesis. Molecular docking and dynamic analyses depicted a stable binding of cyazofamid to the Qi site of the P. insidiosum's cytochrome b orthologous protein. In conclusion, our search for an effective anti-P. insidiosum drug indicated that cyazofamid is a promising candidate for treating pythiosis. With its high efficacy and low toxicity, cyazofamid is a potential chemical for treating pythiosis, reducing the need for radical surgeries, and improving recovery rates. Our findings could pave the way for the development of new and effective treatments for pythiosis.IMPORTANCEPythiosis is a severe infection caused by Pythium insidiosum. The disease is prevalent in tropical/subtropical regions. This infectious condition is challenging to treat with antifungal drugs and often requires surgical removal of the infected tissue. Pythiosis can be fatal if not treated promptly. There is a need for a new treatment that effectively inhibits P. insidiosum. This study screened 17 agricultural fungicides that target plant-pathogenic oomycetes and found that cyazofamid was the most potent in inhibiting P. insidiosum. Cyazofamid showed low toxicity to mammalian cells and high affinity to the P. insidiosum's cytochrome b, which is involved in energy production. Cyazofamid could be a promising candidate for the treatment of pythiosis, as it could reduce the need for surgery and improve the survival rate of patients. This study provides valuable insights into the biology and drug susceptibility of P. insidiosum and opens new avenues for developing effective therapies for pythiosis.

Positive selection and functional diversification of transcription factor Cmr1 homologs in Alternaria.

Transcription factor Cmr1 (Colletotrichum melanin regulation 1) and its homologs in several plant fungal pathogens are the regulators of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis pathway and have evolved functional diversification in morphology and pathogenicity. The fungal genus Alternaria comprises the group of "black fungi" that are rich in DHN-melanin in the primary cell wall and septa of the conidia. Some Alternaria species cause many economically important plant diseases worldwide. However, the evolution and function of Cmr1 homologs in Alternaria remain poorly understood. Here, we identified a total of forty-two Cmr1 homologs from forty-two Alternaria spp. and all contained one additional diverse fungal specific transcription factor motif. Phylogenetic analysis indicated the division of these homologs into five major clades and three branches. Dated phylogeny showed the A and D clades diverged latest and earliest, respectively. Molecular evolutionary analyses revealed that three amino acid sites of Cmr1 homologs in Alternaria were the targets of positive selection. Asmr1, the homolog of Cmr1 in the potato early blight pathogen, Alternaria solani was amplified and displayed the sequence conservation at the amino acid level in different A. solani isolates. Asmr1 was further confirmed to have the transcriptional activation activity and was upregulated during the early stage of potato infection. Deletion of asmr1 led to the decreased melanin content and pathogenicity, deformed conidial morphology, and responses to cell wall and fungicide stresses in A. solani. These results suggest positive selection and functional divergence have played a role in the evolution of Cmr1 homologs in Alternaria. KEY POINTS: • Cmr1 homologs were under positive selection in Alternaria species • Asmr1 is a functional transcription factor, involved in spore development, melanin biosynthesis, pathogenicity, and responses to cell wall and fungicide stresses in A. solani • Cmr1 might be used as a potential taxonomic marker of the genus Alternaria.

Impact of propiconazole fungicide on soil microbiome (bacterial and fungal) diversity, functional profile, and associated dehydrogenase activity.

Pesticides, protect crops but can harm the environment and human health when used without caution. This study evaluated the impact of propiconazole, a fungicide that acts on fungal cell membranes, on soil microbiome abundance, diversity, and functional profile, as well as soil dehydrogenase activity (DHA). The study conducted microcosm experiments using soil samples treated with propiconazole and employed next-generation sequencing (MiSeq) and chromatographic approaches (GC-MS/MS) to analyze the shift in microbial communities and propiconazole level, respectively. The results showed that propiconazole significantly altered the distribution of microbial communities, with notable changes in the abundance of various bacterial and fungal taxa. Among soil bacterial communities, the relative abundance of Proteobacteria and Planctomycetota increased, while that of Acidobacteria decreased after propiconazole treatment. In the fungal communities, propiconazole increased the abundance of Ascomycota and Basidiomycota in the treated soil, while that of Mortierellomycota was reduced. Fungicide application further triggered a significant decrease in DHA over time. Analysis of the functional profile of bacterial communities showed that propiconazole significantly affected bacterial cellular and metabolic pathways. The carbon degradation pathway was upregulated, indicating the microbial detoxification of the contaminant in the treated soil. Our findings suggest that propiconazole application has a discernible impact on soil microbial communities, which could have long-term consequences for soil health, quality, and function.

Complete biodegradation of fungicide carboxin and its metabolite aniline by Delftia sp. HFL-1.

Fungicide carboxin was commonly used in the form of seed coating for the prevention of smut, wheat rust and cotton damping-off, leading carboxin and its probable carcinogenic metabolite aniline to directly enter the soil with the seeds, causing residual pollution. In this study, a novel carboxin degrading strain, Delftia sp. HFL-1, was isolated. Strain HFL-1 could use carboxin as the carbon source for growth and completely degrade 50 mg/L carboxin and its metabolite aniline within 24 h. The optimal temperatures and pH for carboxin degrading by strain HFL-1 were 30 to 42 °C and 5 to 9, respectively. Furthermore, the complete mineralization pathway of carboxin by strain HFL-1 was revealed by High Resolution Mass Spectrometer (HRMS). Carboxin was firstly hydrolyzed into aniline and further metabolized into catechol through multiple oxidation processes, and finally converted into 4-hydroxy-2-oxopentanoate, a precursor of the tricarboxylic acid cycle. Genome sequencing revealed the corresponding degradation genes and cluster of carboxin. Among them, amidohydrolase and dioxygenase were key enzymes involved in the degradation of carboxin and aniline. The discovery of transposons indicated that the aniline degradation gene cluster in strain HFL-1 was obtained via horizontal transfer. Furthermore, the degradation genes were cloned and overexpressed. The in vitro test showed that the expressed degrading enzyme could efficiently degrade aniline. This study provides an efficient strain resource for the bioremediation of carboxin and aniline in contaminated soil, and further revealing the molecular mechanism of biodegradation of carboxin and aniline.

Identification of propranolol and derivatives that are chemical inhibitors of phosphatidate phosphatase as potential broad-spectrum fungicides.

Plant diseases cause enormous economic losses in agriculture and threaten global food security, and application of agrochemicals is an important method of crop disease control. Exploration of disease-resistance mechanisms and synthesis of highly bioactive agrochemicals are thus important research objectives. Here, we show that propranolol, a phosphatidate phosphatase (Pah) inhibitor, effectively suppresses fungal growth, sporulation, sexual reproduction, and infection of diverse plants. The MoPah1 enzyme activity of the rice blast fungus Magnaporthe oryzae is inhibited by propranolol. Alterations in lipid metabolism are associated with inhibited hyphal growth and appressorium formation caused by propranolol in M. oryzae. Propranolol inhibits a broad spectrum of 12 plant pathogens, effectively inhibiting infection of barley, wheat, maize, tomato, and pear. To improve antifungal capacity, we synthesized a series of propranolol derivatives, one of which shows a 16-fold increase in antifungal ability and binds directly to MoPah1. Propranolol and its derivatives can also reduce the severity of rice blast and Fusarium head blight of wheat in the field. Taken together, our results demonstrate that propranolol suppresses fungal development and infection through mechanisms involved in lipid metabolism. Propranolol and its derivatives may therefore be promising candidates for fungicide development.

Impaired spermatogenesis and associated endocrine effects of azole fungicides in peripubertal Xenopus tropicalis.

Early life exposure to endocrine disrupting chemicals (EDCs) has been suggested to adversely affect reproductive health in humans and wildlife. Here, we characterize endocrine and adverse effects on the reproductive system after juvenile exposure to propiconazole (PROP) or imazalil (IMZ), two common azole fungicides with complex endocrine modes of action. Using the frog Xenopus tropicalis, two short-term (2-weeks) studies were conducted. I: Juveniles (2 weeks post metamorphosis (PM)) were exposed to 0, 17 or 178 µg PROP/L. II: Juveniles (6 weeks PM) were exposed to 0, 1, 12 or 154 µg IMZ/L. Histological analysis of the gonads revealed an increase in the number of dark spermatogonial stem cells (SSCs)/testis area, and in the ratio secondary spermatogonia: dark SSCs were increased in all IMZ groups compared to control. Key genes in gametogenesis, retinoic acid and sex steroid pathways were also analysed in the gonads. Testicular levels of 3ß-hsd, ddx4 were increased and cyp19 and id4 levels were decreased in the IMZ groups. In PROP exposed males, increased testicular aldh1a2 levels were detected, but no histological effects observed. Although no effects on ovarian histology were detected, ovarian levels of esr1, rsbn1 were increased in PROP groups, and esr1 levels were decreased in IMZ groups. In conclusion, juvenile azole exposure disrupted testicular expression of key genes in retinoic acid (PROP) and sex steroid pathways and in gametogenesis (IMZ). Our results further show that exposure to environmental concentrations of IMZ disrupted spermatogenesis in the juvenile testis, which is a cause for concern as it may lead to impaired fertility. Testicular levels of id4, ddx4 and the id4:ddx4 ratio were associated with the number of dark SSCs and secondary spermatogonia suggesting that they may serve as a molecular markers for disrupted spermatogenesis.

An enantioselective study of the behavior of the herbicide ethofumesate in agricultural soils: Impact of the addition of organoclays and biochar.

Chiral pesticides that are still commercialized and incorporated into the environment as racemic mixtures of enantiomers require evaluation of the enantioselectivity of their biological activity and environmental fate processes for a better prediction of their field efficacy and environmental risks. In this work, we successfully separated the enantiomers of the chiral herbicide ethofumesate (ETFM), determined their absolute configuration, and characterized their herbicidal activity as well as their adsorption, degradation, enantiomerization, and leaching in Mediterranean agricultural soils. While the herbicidal activity of R-ethofumesate to the sensitive species Portulaca grandiflora was greater than that of S-ethofumesate, the adsorption, degradation, and leaching of the herbicide showed negligible enantioselectivity and enantiomer interconversion did not occur in soils. The adsorption of both enantiomers showed a positive correlation with the soil organic carbon content (r = 0.856, P = 0.015), and their degradation in soils occurred slowly (DT50 > 60 days) and at similar rates independent of their application as individual enantiomers or as a racemic mixture of enantiomers. The addition of three highly adsorptive materials to a scarcely adsorptive soil increased the adsorption of the enantiomers of ETFM and delayed their degradation without affecting the non-enantioselective character of the processes. As a result of their high adsorption capacity, the materials were highly effective in reducing the leaching of both enantiomers of ETFM through soil columns. The results of this work indicate that the application of single-enantiomer ETFM formulations, based on a higher herbicidal activity or a lower toxicity to non-target organisms of the formulated enantiomer, would reduce considerable exposure risks associated with incorporating into the environment the less favorable enantiomer, as this would show long persistence and high leaching potential in soils similar to its optical isomer.

Arabinose Plays an Important Role in Regulating the Growth and Sporulation of Bacillus subtilis NCD-2.

A microbial fungicide developed from Bacillus subtilis NCD-2 has been registered for suppressing verticillium wilt in crops in China. Spores are the main ingredient of this fungicide and play a crucial role in suppressing plant disease. Therefore, increasing the number of spores of strain NCD-2 during fermentation is important for reducing the cost of the fungicide. In this study, five kinds of carbon sources were found to promote the metabolism of strain NCD-2 revealed via Biolog Phenotype MicroArray (PM) technology. L-arabinose showed the strongest ability to promote the growth and sporulation of strain NCD-2. L-arabinose increased the bacterial concentration and the sporulation efficiency of strain NCD-2 by 2.04 times and 1.99 times compared with D-glucose, respectively. Moreover, L-arabinose significantly decreased the autolysis of strain NCD-2. Genes associated with arabinose metabolism, sporulation, spore resistance to heat, and spore coat formation were significantly up-regulated, and genes associated with sporulation-delaying protein were significantly down-regulated under L-arabinose treatment. The deletion of msmX, which is involved in arabinose transport in the Bacillus genus, decreased growth and sporulation by 53.71% and 86.46% compared with wild-type strain NCD-2, respectively. Complementing the mutant strain by importing an intact msmX gene restored the strain's growth and sporulation.