Recent Advances in Design and Development of Diazole and Diazine Based Fungicides (2014-2023).

With fungal diseases posing a major threat to agricultural production, the application of fungicides to control related diseases is often considered necessary to ensure the world's food supply. The search for new bioactive agents has long been a priority in crop protection due to the continuous development of resistance against currently used types of active compounds. Heterocyclic compounds are an inseparable part of the core structures of numerous lead compounds, these rings constitute pharmacophores of a significant number of fungicides developed over the past decade by agrochemists. Among heterocycles, nitrogen-based compounds play an essential role. To date, diazole (imidazole and pyrazole) and diazine (pyrimidine, pyridazine, and pyrazine) derivatives make up an important series of synthetic fungicides. In recent years, many reports have been published on the design, synthesis, and study of the fungicidal activity of these scaffolds, but there was a lack of a comprehensive classified review on nitrogen-containing scaffolds. Regarding this issue, here we have reviewed the published articles on the fungicidal activity of the diazole and diazine families. In current review, we have classified the molecules synthesized so far based on the size of the ring.

Toxicological insight of metiram: immuno-oxidative, neuro-behavioral, and hemato-biochemical changes during acute exposure of Nile tilapia (Oreochromis niloticus).

BACKGROUND: The inappropriate use of pesticides including fungicides creates severe biological hazards that can endanger fish health and impede sustainable aquaculture. OBJECTIVE: This study investigated the negative impacts of metiram (MET), a fungicide on the health status of Nile tilapia (Oreochromis niloticus) for a 96-hour duration as an acute exposure in a static renewal system. METHODS: Three hundred fish (average body weight: 37.50 ± 0.22 g) were assigned into six groups (50 fish/group) with five replicates (10 fish/replicate). Fish were exposed to various six concentrations (0, 1.5, 3, 4.5, 6, and 7.5 mg/L) of MET as a water exposure to for 96-hour without water exchange. The fish's behavior, clinical signs, and mortalities were documented every day of the exposure period. Additionally, MET's impact on blood profile, stress biomarkers, hepato-renal functions, immune-antioxidant status, and brain biomarker were closely monitored. RESULTS: The lethal concentration (LC50) of MET estimated using Finney's probit technique was 3.77 mg/L. The fish's behavior was severely impacted by acute MET exposure, as clear by an increase in surfacing, loss of equilibrium, unusual swimming, laterality, abnormal movement, and a decline in aggressive behaviors. The survivability and hematological indices (white and red blood cell count, differential white blood cell count, hematocrit value, and hemoglobin) were significantly reduced in a concentration-dependent manner following MET exposure. Acute exposure to MET (1.5-7.5 mg/L) incrementally increased stress biomarkers (nor-epinephrine, cortisol, and glucose), lipid peroxides (malondialdehyde), and brain oxidative DNA damage biomarker (8-hydroxy-2-deoxyguanosine). A hepato-renal dysfunction by MET exposure (4.5-7.5 mg/L) was evidenced by the significant increase in the alanine and aspartate aminotransferases and creatinine values. Moreover, a substantial decline in the immune parameters (lysozyme, complement 3, serum bactericidal activity, and antiprotease activity) and antioxidant variables (total antioxidant capacity, superoxide dismutase, and glutathione peroxidase) resulted from acute MET exposure. CONCLUSION: According to these findings, the 96-hour LC50 of MET in Nile tilapia was 3.77 mg/L. MET exposure triggered toxicity in Nile tilapia, as seen by alterations in fish neuro-behaviors, immune-antioxidant status, hepato-renal functioning, and signifying physiological disturbances. This study emphasizes the potential ecological dangers provoked by MET as an environmental contaminant to aquatic systems. However, the long-term MET exposure is still needed to be investigated.

Microbial fungicides can positively affect aubergine photosynthetic properties, soil enzyme activity and microbial community structure.

Background: This study examined the effects of microbial agents on the enzyme activity, microbial community construction and potential functions of inter-root soil of aubergine (Fragaria × ananassa Duch.). This study also sought to clarify the adaptability of inter-root microorganisms to environmental factors to provide a theoretical basis for the stability of the microbiology of inter-root soil of aubergine and for the ecological preservation of farmland soil. Methods: Eggplant inter-root soils treated with Bacillus subtilis (QZ_T1), Bacillus subtilis (QZ_T2), Bacillus amyloliquefaciens (QZ_T3), Verticillium thuringiensis (QZ_T4) and Verticillium purpureum (QZ_T5) were used to analyse the effects of different microbial agents on the inter-root soils of aubergine compared to the untreated control group (QZ_CK). The effects of different microbial agents on the characteristics and functions of inter-root soil microbial communities were analysed using 16S rRNA and ITS (internal transcribed spacer region) high-throughput sequencing techniques. Results: The bacterial diversity index and fungal diversity index of the aubergine inter-root soil increased significantly with the application of microbial fungicides; gas exchange parameters and soil enzyme activities also increased. The structural and functional composition of the bacterial and fungal communities in the aubergine inter-root soil changed after fungicide treatment compared to the control, with a decrease in the abundance of phytopathogenic fungi and an increase in the abundance of beneficial fungi in the soil. Enhancement of key community functions, reduction of pathogenic fungi, modulation of environmental factors and improved functional stability of microbial communities were important factors contributing to the microbial stability of fungicide-treated aubergine inter-root soils.

Discovery of Novel Spiropiperidinyl-α-methylene-γ-butyrolactones as Antifungal and Antitoxin Agents Targeting Oxysterol Binding Protein.

Corn ear rot and fumonisin caused by Fusarium verticillioides pose a serious threat to food security. To find more highly active fungicidal and antitoxic candidates with structure diversity based on naturally occurring lead xanthatin, a series of novel spiropiperidinyl-α-methylene-γ-butyrolactones were rationally designed and synthesized. The in vitro bioassay results indicated that compound 7c showed broad-spectrum in vitro activity with EC50 values falling from 3.51 to 24.10 µg/mL against Rhizoctonia solani and Alternaria solani, which was more active than the positive controls xanthatin and oxathiapiprolin. In addition, compound 7c also showed good antitoxic efficacy against fumonisin with a 48% inhibition rate even at a concentration of 20 µg/mL. Fluorescence quenching and the molecular docking validated both 7c and oxathiapiprolin targeting at FvoshC. RNA sequencing analysis discovered that FUM gene cluster and protein processing in endoplasmic reticulum were downregulated. Our studies have discovered spiropiperidinyl-α-methylene-γ-butyrolactone as a novel FvoshC target-based scaffold for fungicide lead with antitoxin activity.

Expanding the Structural Diversity of Tubulin-Targeting Agents: Development of Highly Potent Benzimidazoles for Treating Fungal Diseases.

Benzimidazoles, the representative pharmacophore of fungicides, have excellent antifungal potency, but their simple structure and single site of action have hindered their wider application in agriculture. In order to extend the structural diversity of tubulin-targeted benzimidazoles, novel benzimidazole derivatives were prepared by introducing the attractive pyrimidine pharmacophore. 2-((6-(4-(trifluoromethyl)phenoxy)pyrimidin-4-yl)thio)-1H-benzo[d]imidazole (A25) exhibited optimal antifungal activity against Sclerotinia sclerotiorum (S. s.), affording an excellent half-maximal effective concentration (EC50) of 0.158 µg/mL, which was higher than that of the reference agent carbendazim (EC50 = 0.594 µg/mL). Pot experiments revealed that compound A25 (200 µg/mL) had acceptable protective activity (84.7%) and curative activity (78.1%), which were comparable with that of carbendazim (protective activity: 90.8%; curative activity: 69.9%). Molecular docking displayed that multiple hydrogen bonds and π-π interactions could be formed between A25 and ß-tubulin, resulting in a stronger bonding effect than carbendazim. Fluorescence imaging revealed that the structure of intracellular microtubules can be changed significantly after A25 treatment. Overall, these remarkable antifungal profiles of constructed novel benzimidazole derivatives could facilitate the application of novel microtubule-targeting agents.

Unveiling the Mechanism of Phenamacril Resistance in F. graminearum: Computational and Experimental Insights into the C423A Mutation in FgMyoI.

Phenamacril (PHA) is a highly selective fungicide for controlling fusarium head blight (FHB) mainly caused by F. graminearum and F. asiaticum. However, the C423A mutation in myosin I of F. graminearum (FgMyoI) leads to natural resistance to PHA. Here, based on the computational approaches and biochemical validation, we elucidate the atomic-level mechanism behind the natural resistance of F. graminearum to the fungicide PHA due to the C423A mutation in FgMyoI. The mutation leads to a rearrangement of pocket residues, resulting in increased size and flexibility of the binding pocket, which impairs the stable binding of PHA. MST experiments confirm that the mutant protein FgMyoIC423A exhibits significantly reduced affinity for PHA compared to wild-type FgMyoI and the nonresistant C423K mutant. This decreased binding affinity likely underlies the development of PHA resistance in F. graminearum. Conversely, the nonresistant C423K mutant retains sensitivity to PHA due to the introduction of a strong hydrogen bond donor, which facilitates stable binding of PHA in the pocket. These findings shed light on the molecular basis of PHA resistance and provide new directions for the creation of new myosin inhibitors.

Deciphering the mechanisms involved in reduced sensitivity to azoles and fengycin lipopeptide in Venturia inaequalis.

Apple scab, caused by the hemibiotrophic fungus Venturia inaequalis, is currently the most common and damaging disease in apple orchards. Two strains of V. inaequalis (S755 and Rs552) with different sensitivities to azole fungicides and the bacterial metabolite fengycin were compared to determine the mechanisms responsible for these differences. Antifungal activity tests showed that Rs552 had reduced sensitivity to tebuconazole and tetraconazole, as well as to fengycin alone or in a binary mixture with other lipopeptides (iturin A, pumilacidin, lichenysin). S755 was highly sensitive to fengycin, whose activity was close to that of tebuconazole. Unlike fengycin, lipopeptides from the iturin family (mycosubtilin, iturin A) had similar activity on both strains, while those from the surfactin family (lichenysin, pumilacidin) were not active, except in binary mixtures with fengycin. The activity of lipopeptides varies according to their family and structure. Analyses to determine the difference in sensitivity to azoles (which target the CYP51 enzyme involved in the ergosterol biosynthesis pathway) showed that the reduced sensitivity in Rs552 is linked to (i) a constitutive increased expression of the Cyp51A gene caused by insertions in the upstream region and (ii) greater efflux by membrane pumps with the involvement of ABC transporters. Microscopic observations revealed that fengycin, known to interact with plasma membranes, induced morphological and cytological changes in cells from both strains. Sterol and phospholipid analyses showed a higher level of ergosta-7,22-dien-3-ol and a lower level of PI(C16:0/C18:1) in Rs552 compared with S755. These differences could therefore influence the composition of the plasma membrane and explain the differential sensitivity of the strains to fengycin. However, the similar antifungal activities of mycosubtilin and iturin A in the two strains indirectly indicate that sterols are probably not involved in the fengycin resistance mechanism. This leads to the conclusion that different mechanisms are responsible for the difference in susceptibility to azoles or fengycin in the strains studied.

Acute toxicity of the fungicide captan to honey bees and mixed evidence for synergism with the insecticide thiamethoxam.

Honey bees are commonly co-exposed to pesticides during crop pollination, including the fungicide captan and neonicotinoid insecticide thiamethoxam. We assessed the impact of exposure to these two pesticides individually and in combination, at a range of field-realistic doses. In laboratory assays, mortality of larvae treated with captan was 80-90% greater than controls, dose-independent, and similar to mortality from the lowest dose of thiamethoxam. There was evidence of synergism (i.e., a non-additive response) from captan-thiamethoxam co-exposure at the highest dose of thiamethoxam, but not at lower doses. In the field, we exposed whole colonies to the lowest doses used in the laboratory. Exposure to captan and thiamethoxam individually and in combination resulted in minimal impacts on population growth or colony mortality, and there was no evidence of synergism or antagonism. These results suggest captan and thiamethoxam are each acutely toxic to immature honey bees, but whole colonies can potentially compensate for detrimental effects, at least at the low doses used in our field trial, or that methodological differences of the field experiment impacted results (e.g., dilution of treatments with natural pollen). If compensation occurred, further work is needed to assess how it occurred, potentially via increased queen egg laying, and whether short-term compensation leads to long-term costs. Further work is also needed for other crop pollinators that lack the social detoxification capabilities of honey bee colonies and may be less resilient to pesticides.

Kinetic and Mechanistic Modelling of Pyrimethanil Fungicide Adsorption onto Soils of Varying Physico-chemical Properties.

Pesticide transport in the environment is impacted by the kinetics of its adsorption onto soil. The adsorption kinetics of pyrimethanil was investigated in ten soil samples of varying physicochemical properties. The highest adsorption was in the soil having the maximum silt and CaCO3 contents, pH and electrical conductance but the lowest amorphous Fe oxides and CaCl2 extractable Mn. Pseudo-second order kinetics and intra-particle diffusion model best accounted the adsorption kinetics of pyrimethanil. The equilibrium adsorption estimated by pseudo-second order kinetics (q02) was significantly and positively correlated with CaCl2 extractable Cu content (r = 0.709) while rate coefficient (k02) had a negative correlation with crystalline iron oxides content (r = -0.675). The intra-particle diffusion coefficient (ki.d.) had inverse relationship with CaCl2 extractable Mn content in soils (r = -0.689). FTIR spectra showed a significant interaction of pyrimethanil with micronutrient cations. Adsorption kinetic parameters of pyrimethanil could be successfully predicted by soil properties. The findings may help to evolve fungicide management decisions.

Biofungicides Based on Plant Extracts: On the Road to Organic Farming.

Phytopathogenic fungi are responsible for diseases in commercially important crops and cause major supply problems in the global food chain. Plants were able to protect themselves from disease before humans played an active role in protecting plants. They are known to synthesize a variety of secondary metabolites (SMs), such as terpenes, alkaloids, and phenolic compounds, which can be extracted using conventional and unconventional techniques to formulate biofungicides; plant extracts have antifungal activity and various mechanisms of action against these organisms. In addition, they are considered non-phytotoxic and potentially effective in disease control. They are a sustainable and economically viable alternative for use in agriculture, which is why biofungicides are increasingly recognized as an attractive option to solve the problems caused by synthetic fungicides. Currently, organic farming continues to grow, highlighting the importance of developing environmentally friendly alternatives for crop production. This review provides a compilation of the literature on biosynthesis, mechanisms of action of secondary metabolites against phytopathogens, extraction techniques and formulation of biofungicides, biological activity of plant extracts on phytopathogenic fungi, regulation, advantages, disadvantages and an overview of the current use of biofungicides in agriculture.

Tebuconazole Induces Mouse Fetal Testes Damage via ROS Generation in an Organ Culture Method.

The fungicide tebuconazole (TEB) poses risks to human and animal health via various exposure routes. It induces toxicity in multiple organs and disrupts reproductive health by affecting steroid hormone synthesis and fetal development. In this study, we investigated the impact of TEB on fetal testes using in vitro models, focusing on germ, Sertoli, and Leydig cells, and explored the mechanisms underlying cellular damage. The results revealed significant damage to germ cells and disruption of Leydig cell development. TEB exposure led to a decrease in germ cell numbers, as indicated by histological and immunostaining analyses. TEB induced the up- and down-regulation of the expression of fetal and adult Leydig cell markers, respectively. Additionally, TEB-treated fetal testes exhibited increased expression of oxidative-stress-related genes and proteins. However, co-treatment with the antioxidant N-acetylcysteine mitigated TEB-induced germ cell damage and prevented abnormal Leydig cell development. These findings suggest that administration of antioxidants can prevent the intratesticular damage typically caused by TEB exposure.

Unveiling the ecotoxicological effects of azoxystrobin-based fungicides at realistic concentrations on the land snail, Theba pisana.

The ecotoxicological consequences of azoxystrobin on land snails have not yet been addressed. Therefore, the present study aims to provide novel data on the threat of a commercial grade azoxystrobin (AMISTAR) at two environmentally relevant concentrations (0.3 µg/ml) and tenfold (3 µg/ml) on the model species, Theba pisana by physiological, biochemical, and histopathological markers for 28 days. Our results showed a reduction in animal food consumption and growth due to exposure to both azoxystrobin concentrations. It also induced oxidative stress and led to a significant decrease in lipid peroxidation (LPO) levels after 7 days of exposure, while the opposite effect occurred after 28 days. Except for the 7-day exposure, all treated snails had significantly reduced glutathione (GSH) content and increased catalase (CAT) activity at all-time intervals. Glutathione peroxidase (GPx), glutathione-S-transferase (GST) activities, and protein content (PC) were elevated in treated snails at all-time intervals. Moreover, alterations in acetylcholinesterase (AChE) activity between a decrease and an increase were noticed. Additionally, azoxystrobin exerted changes in T. pisana hepatopancreas architecture. Our study suggests that azoxystrobin may have negative ecological consequences for T. pisana and highlights its potential risks to the natural environment.

Antifungal Activity and Mechanism of Physcion against Sclerotium rolfsii, the Causal Agent of Peanut Southern Blight.

Peanut southern blight, caused by the soil-borne pathogen Sclerotium rolfsii, is a widespread and devastating epidemic. Frequently, it is laborious to effectively control by labor-intensive foliar sprays of agrochemicals due to untimely find. In the present study, seed treatment with physcion (PHY) at doses of 0.08, 0.16, and 0.32 g AI kg-1 seed significantly improved the growth and photosynthetic activity of peanuts. Furthermore, PHY seed treatment resulted in an elevated enzymatic activity of key enzymes in peanut roots, including peroxidase, superoxide dismutase, polyphenol oxidase, catalase, lipoxygenase, and phenylalanine ammonia-lyase, as well as an increase in callus accumulation and lignin synthesis at the infection site, ultimately enhancing the root activity. This study revealed that PHY seed treatment could promote the accumulation of reactive oxygen species, salicylic acid (SA), and jasmonic acid (JA)/ethylene (ET) in peanut roots, while also decreasing the content of malondialdehyde levels in response to S. rolfsii infection. The results were further confirmed by transcriptome data and metabolomics. These findings suggest that PHY seed treatment activates the plant defense pathways mediated by SA and JA/ET in peanut roots, enhancing the resistance of peanut plants to S. rolfsii. In short, PHY is expected to be developed into a new plant-derived immunostimulant or fungicide to increase the options and means for peanut disease control.

Metabolism of a fungicide propiconazole by Cunninghamella elegans ATCC36112.

The metabolic breakdown of propiconazole by fungi was examined, and it was found that the microbial model (Cunninghamella elegans ATCC36112) efficiently degrades the triazole fungicide propiconazole through the action of cytochrome P450. This enzyme primarily facilitates the oxidation and hydrolysis processes involved in phase I metabolism. We observed major metabolites indicating hydroxylation/oxidation of propyl groups of propiconazole. Around 98% of propiconazole underwent degradation within a span of 3 days post-treatment, leading to the accumulation of five metabolites (M1-M5). The experiments started with a preliminary identification of propiconazole and its metabolites using GC-MS. The identified metabolites were then separated and identified by in-depth analysis using preparative UHPLC and MS/MS. The metabolites of propiconazole are M1 (CGA-118245), M2(CGA-118244), M3(CGA-136735), M4(GB-XLIII-42-1), and M5(SYN-542636). To further investigate the role of key enzymes in potential fungi, we treated the culture medium with piperonyl butoxide (PB) and methimazole (MZ), and then examined the kinetic responses of propiconazole and its metabolites. The results indicated a significant reduction in the metabolism rate of propiconazole in the medium treated with PB, while methimazole showed weaker inhibitory effects on the metabolism of propiconazole in the fungus C. elegans.

Combined interaction of fungicides binary mixtures: experimental study and machine learning-driven QSAR modeling.

Fungicide mixtures are an effective strategy in delaying the development of fungicide resistance. In this research, a fixed ratio ray design method was used to generate fifty binary mixtures of five fungicides with diverse modes of action. The interaction of these mixtures was then analyzed using CA and IA models. QSAR modeling was conducted to assess their fungicidal activity through multiple linear regression (MLR), support vector machine (SVM), and artificial neural network (ANN). Most mixtures exhibited additive interaction, with the CA model proving more accurate than the IA model in predicting fungicidal activity. The MLR model showed a good linear correlation between selected theoretical descriptors by the genetic algorithm and fungicidal activity. However, both ML-based models demonstrated better predictive performance than the MLR model. The ANN model showed slightly better predictability than the SVM model, with R2 and R2cv at 0.91 and 0.81, respectively. For external validation, the R2test value was 0.845. In contrast, the SVM model had values of 0.91, 0.78, and 0.77 for the same metrics. In conclusion, the proposed ML-based model can be a valuable tool for developing potent fungicidal mixtures to delay fungicidal resistance emergence.

Analytical challenges related to the measurement of chlorothalonil in serum in the perspective of human biomonitoring studies.

Chlorothalonil (CTN) is a popular fungicide widely used in the world. However, its determination in serum samples is highly challenging, preventing a reliable investigation of human CTN internal exposure. We first investigated CTN's behaviour all along this analytical process on spiked serum samples. We used a radiolabelled 14C-CTN standard to monitor CTN in spiked serum samples and observed (1) a complete degradation of CTN in deproteinised serum samples after 4 h of contact; (2) a strong interaction between serum proteins and CTN by-products, with only 20 % of the radioactivity found to be extractable after 24 h of contact and (3) a slightly improved stability of CTN in serum following a first step of acidification or EDTA addition to samples. Using liquid chromatography coupled to high resolution mass spectrometry, 4-hydroxy-2,5,6-trichloroisophthalonitrile (HCTN) was identified as the major serum by-product of CTN. A protocol was developed to monitor both extractable CTN and HCTN from serum. This method was implemented on 36 human adult serum samples from the French "Esteban" Cohort. No free CTN was identified in these serum samples. Conversely, HCTN was detected in all samples at concentrations around 15 ± 2 ng mL-1, corresponding to the extractable fraction of CTN. Thus, HCTN may constitute a relevant biomarker of human internal exposure. Of note, the potential CTN contamination during blood collection could also be a source of HCTN detection in serum samples. Finally, blood sampling in EDTA tubes would seem more appropriate than in dry tubes for any future internal exposure studies on CTN.

Toxicogenetic, biochemical, and physiological effects of azoxystrobin and carbendazim fungicides over Lactuca sativa L. and Phaseolus vulgaris L.

Fungicides are pesticides that are frequently used in agriculture because of their action against fungal diseases. However, the widespread application of pesticides around the world raises environmental and public health concerns, since these compounds are toxic and can pose risks to ecosystems and human health. The aim of this study was to evaluate the phytotoxic, cytogenotoxic, and biochemical effects of azoxystrobin and carbendazim on Lactuca sativa L. and their physiological effects on Phaseolus vulgaris L. by analyzing the cell cycle and chromosomal and nuclear alterations in L. sativa; the biochemical effects of azoxystrobin and carbendazim on Phaseolus vulgaris L. and their physiological effects on Phaseolus vulgaris L. by analyzing the cell cycle and chromosomal and nuclear alterations in L. sativa; the biochemical effects by analyzing the activity of antioxidant enzymes in L. sativa; and the physiological effects by analyzing chlorophyll content and chlorophyll a fluorescence in P. vulgaris. It was observed that both fungicides were phytotoxic and cytotoxic, reducing root growth and the mitotic index, cytogenotoxic, increasing the occurrence of chromosomal alterations, as well as inducing oxidative stress and an increase in chlorophyll fluorescence emission and altered energy absorption in the plants used as a test system. In view of this, studies such as the one presented here indicate that the use of pesticides, even in small quantities, can lead to damage to the metabolism of plant organisms.

Environmental Hot Spots and Resistance-Associated Application Practices for Azole-Resistant Aspergillus fumigatus, Denmark, 2020-2023.

Azole-resistant Aspergillus fumigatus (ARAf) fungi have been found inconsistently in the environment in Denmark since 2010. During 2018-2020, nationwide surveillance of clinical A. fumigatus fungi reported environmental TR34/L98H or TR46/Y121F/T289A resistance mutations in 3.6% of isolates, prompting environmental sampling for ARAf and azole fungicides and investigation for selection of ARAf in field and microcosmos experiments. ARAf was ubiquitous (20% of 366 samples; 16% TR34/L98H- and 4% TR46/Y121F/T289A-related mechanisms), constituting 4.2% of 4,538 A. fumigatus isolates. The highest proportions were in flower- and compost-related samples but were not correlated with azole-fungicide application concentrations. Genotyping showed clustering of tandem repeat-related ARAf and overlaps with clinical isolates in Denmark. A. fumigatus fungi grew poorly in the field experiment with no postapplication change in ARAf proportions. However, in microcosmos experiments, a sustained complete (tebuconazole) or partial (prothioconazole) inhibition against wild-type A. fumigatus but not ARAf indicated that, under some conditions, azole fungicides may favor growth of ARAf in soil.

The mechanistic insights of essential oil of Mentha piperita to control Botrytis cinerea and the prospection of lipid nanoparticles to its application.

Botrytis cinerea is the phytopathogenic fungus responsible for the gray mold disease that affects crops worldwide. Essential oils (EOs) have emerged as a sustainable tool to reduce the adverse impact of synthetic fungicides. Nevertheless, the scarce information about the physiological mechanism action and the limitations to applying EOs has restricted its use. This study focused on elucidating the physiological action mechanisms and prospection of lipid nanoparticles to apply EO of Mentha piperita. The results showed that the EO of M. piperita at 500, 700, and 900 µL L-1 inhibited the mycelial growth at 100 %. The inhibition of spore germination of B. cinerea reached 31.43 % at 900 µL L-1. The EO of M. piperita decreased the dry weight and increased pH, electrical conductivity, and cellular material absorbing OD260 nm of cultures of B. cinerea. The fluorescence technique revealed that EO reduced hyphae width, mitochondrial activity, and viability, and increased ROS production. The formulation of EO of M. piperita loaded- solid lipid nanoparticles (SLN) at 500, 700, and 900 µL L-1 had particle size ∼ 200 nm, polydispersity index < 0.2, and stability. Also, the thermogravimetric analysis indicated that the EO of M. piperita-loaded SLN has great thermal stability at 50 °C. EO of M. piperita-loaded SLN reduced the mycelial growth of B. cinerea by 70 %, while SLN formulation (without EO) reached 42 % inhibition. These results supported that EO of M. piperita-loaded SLN is a sustainable tool for reducing the disease produced by B. cinerea.

Design, Synthesis, and Antifungal Activities of Novel Potent Fluoroalkenyl Succinate Dehydrogenase Inhibitors.

The development of new fungicide molecules is a crucial task for agricultural chemists to enhance the effectiveness of fungicides in agricultural production. In this study, a series of novel fluoroalkenyl modified succinate dehydrogenase inhibitors were synthesized and evaluated for their antifungal activities against eight fungi. The results from the in vitro antifungal assay demonstrated that compound 34 exhibited superior activity against Rhizoctonia solani with an EC50 value of 0.04 µM, outperforming commercial fluxapyroxad (EC50 = 0.18 µM) and boscalid (EC50 = 3.07 µM). Furthermore, compound 34 showed similar effects to fluxapyroxad on other pathogenic fungi such as Sclerotinia sclerotiorum (EC50 = 1.13 µM), Monilinia fructicola (EC50 = 1.61 µM), Botrytis cinerea (EC50 = 1.21 µM), and also demonstrated protective and curative efficacies in vivo on rapeseed leaves and tomato fruits. Enzyme activity experiments and protein-ligand interaction analysis by surface plasmon resonance revealed that compound 34 had a stronger inhibitory effect on succinate dehydrogenase compared to fluxapyroxad. Additionally, molecular docking and DFT calculation confirmed that the fluoroalkenyl unit in compound 34 could enhance its binding capacity with the target protein through p-π conjugation and hydrogen bond interactions.