Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.281
Filtrar
1.
Chemosphere ; 287(Pt 1): 131902, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34438209

RESUMO

Understanding the lethal effects of pesticides nano formulations on the targeted organisms (pathogens) and the non-targeted organisms (fish, earthworms, etc) is essential in assessing the probable impact of new technologies on agriculture and environment. Here we evaluated the bioactivity and the biotoxicity of new type of fungicide smart-delivery formulation based on conjugating carboxymethylated-ß-glucans on the mesoporous silica nanoparticles (MSNs) surface after loading chlorothalonil (CHT) fungicide in the MSNs pores. The obtained formulation has been characterized with FE-SEM, and HR-TEM. The CHT loading efficiency has been measured with TGA. The bioactivity of the obtained formulation (CHT@MSNs-ß-glucans) has been tested against four pathogens, fusarium head blight (Fusarium graminearum), sheath rot (Sarocladium oryzae), rice sheath blight (Rhizoctonia solani), and soyabean anthracnose (Colletotrichum truncatum) compared with CHT WP 75% commercial formulation (CHT-WP) and technical CHT. The environmental biotoxicity of CHT@MSNs-ß-glucans compared with CHT-WP has been tested toward earthworm (Eisenia fetida) and zebra fish (Danio rerio). The results showed that CHT@MSNs-ß-glucans has an excellent bioactivity against the subjected pathogens with better inhabiting effects than CHT-WP. CHT@MSNs-ß-glucans toxicity to Eisenia fetida was found 2.25 times lower than CHT-WP toxicity. The LC50 of CHT@MSNs-ß-glucans to zebra fish after the first 24h was 2.93 times higher than CHT-WP. After 96h of treatment, the LC50 of CHT@MSNs-ß-glucans was 2.66 times higher than CHT-WP. This work highlighted the necessity to increase the mandatory bioassays of nano formulations with the major non-target organisms in the environmental risk assessment of new pesticide formulations.


Assuntos
Fungicidas Industriais , Nanopartículas , beta-Glucanas , Animais , Colletotrichum , Portadores de Fármacos , Fungicidas Industriais/toxicidade , Fusarium , Hypocreales , Nanopartículas/toxicidade , Nitrilas , Porosidade , Rhizoctonia , Dióxido de Silício/toxicidade , beta-Glucanas/toxicidade
2.
J Nanosci Nanotechnol ; 21(6): 3547-3555, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34739806

RESUMO

Biogenically synthesized silver and gold nanoparticles were evaluated for antifungal activity against Rhizoctonia solani causing sheath blight of rice. Both the nanoparticles were tested at 1, 5, 10, 50, 100 and 200 ppm along with chemical check against the pathogen. Silver nanoparticle (Ag NP) at 200 ppm showed the highest inhibition (73.39%) in the radial growth of R. solani, while gold nanoparticle (Au NP) at the same concentration inhibited the growth of the pathogen up to 60.83%. Study on mode of action of nanoparticle by electron microscopy showed that Ag NP accumulate inside the fungal cells thereby cause distortion of fungal cells leading to death of the pathogen. Ag NP at 200 and 100 ppm caused complete inhibition of sclerotial germination of R. solani. Pot experiment conducted to study the efficacy of Ag NP at 200 ppm against sheath blight of rice showed that application of Ag NP increased the plant growth parameters as compared to control, with reduced per cent disease incidence (20.00%) as compared to inoculated control R. solani (88.00%). Application of Ag NP also increased the concentration of vital secondary metabolites like phenols, flavonoids, terpenoids and total soluble sugars.


Assuntos
Nanopartículas Metálicas , Oryza , Antifúngicos/farmacologia , Ouro , Doenças das Plantas , Rhizoctonia , Prata/farmacologia
3.
J Agric Food Chem ; 69(45): 13448-13459, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34748325

RESUMO

Diversity of pesticide discovery provided a solution to resistance. Here, we presented a strategy of azo-incorporating to promote the diverse developments of fungicide. A series of novel fungicides were synthesized by incorporating azobenzene derivatives into fluxapyroxad. Much better in vitro fungicidal activity increases for compound 9d were observed compared to the positive control, fluxapyroxad against Botrytis cinerea and Rhizoctonia solani. Compound 9d (IC50 = 0.03 µM) also had a great enzyme-inhibiting activity increase toward succinate dehydrogenase in comparison with fluxapyroxad (IC50 = 4.40 µM). A comparatively equivalent biological activity was observed between compounds 8a and 9d. SEM analysis helped us to observe clearly the morphology of the fungi before and after active ingredient delivery. Our results of molecular docking analysis, fluorescence quenching analysis, and enzymatic assays demonstrated that compound 8a and 9d act on SDH. An increase in inhibitory activity could be occurring after incorporation of azobenzene, which provided a new strategy for molecular design in pesticide discovery.


Assuntos
Ascomicetos , Fungicidas Industriais , Ascomicetos/metabolismo , Botrytis , Fungicidas Industriais/farmacologia , Simulação de Acoplamento Molecular , Rhizoctonia/metabolismo , Relação Estrutura-Atividade , Succinato Desidrogenase/metabolismo
4.
Exp Parasitol ; 230: 108176, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34740586

RESUMO

Foliar spray of silicon dioxide (SiO2 NPs), zinc oxide (ZnO NPs) and titanium dioxide (TiO2 NPs) nanoparticles were used for the management of Meloidogyne incognita, Alternaria dauci and Rhizoctonia solani disease complex of carrot. Foliar spray of SiO2 NPs/ZnO NPs or TiO2 NPs increased plant growth attributes, chlorophyll and carotenoid of carrot. Foliar spray of 0.10 mg ml-1 SiO2 NPs caused the highest increase in plant growth, chlorophyll and carotenoid content of leaves followed by spray of 0.10 mg ml-1 ZnO NPs, 0.05 mg ml-1 SiO2 NPs, 0.05 mg ml-1 ZnO NPs, 0.10 mg ml-1 TiO2 NPs and 0.05 mg ml-1 TiO2 NPs. Use of SiO2 NPs caused a higher reduction in root galling, nematode multiplication and disease indices followed by ZnO NPs and TiO2 NPs. Two principal components analysis showed a total of 97.84% overall data variance in plants inoculated with single pathogen and 97.20% in plants inoculated with two or more pathogens. Therefore, foliar spray of SiO2 NPs appears interesting for the management of disease complex of carrot.


Assuntos
Alternaria/efeitos dos fármacos , Daucus carota , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Rhizoctonia/efeitos dos fármacos , Tylenchoidea/efeitos dos fármacos , Aerossóis , Alternaria/crescimento & desenvolvimento , Alternaria/patogenicidade , Animais , Carotenoides/análise , Clorofila/análise , Daucus carota/crescimento & desenvolvimento , Daucus carota/microbiologia , Daucus carota/parasitologia , Microscopia de Fluorescência , Nanopartículas/administração & dosagem , Folhas de Planta/química , Análise de Componente Principal , Rhizoctonia/crescimento & desenvolvimento , Rhizoctonia/patogenicidade , Dióxido de Silício/farmacologia , Titânio/farmacologia , Tylenchoidea/patogenicidade , Óxido de Zinco/farmacologia
5.
J Agric Food Chem ; 69(41): 12156-12170, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34623798

RESUMO

Enlightened from our previous work of structural simplification of quinine and innovative application of natural products against phytopathogenic fungi, lead structure 2,8-bis(trifluoromethyl)-4-quinolinol (3) was selected to be a candidate and its diversified design, synthesis, and antifungal evaluation were carried out. All of the synthesized compounds Aa1-Db1 were evaluated for their antifungal activity against four agriculturally important fungi, Botrytis cinerea, Fusarium graminearum, Rhizoctonia solani, and Sclerotinia sclerotiorum. Results showed that compounds Ac3, Ac4, Ac7, Ac9, Ac12, Bb1, Bb10, Bb11, Bb13, Cb1. and Cb3 exhibited a good antifungal effect, especially Ac12 had the most potent activity with EC50 values of 0.52 and 0.50 µg/mL against S. sclerotiorum and B. cinerea, respectively, which were more potent than those of the lead compound 3 (1.72 and 1.89 µg/mL) and commercial fungicides azoxystrobin (both >30 µg/mL) and 8-hydroxyquinoline (2.12 and 5.28 µg/mL). Moreover, compound Ac12 displayed excellent in vivo antifungal activity, which was comparable in activity to the commercial fungicide boscalid. The preliminary mechanism revealed that compound Ac12 might cause an abnormal morphology of cell membranes, an increase in membrane permeability, and release of cellular contents. These results indicated that compound Ac12 displayed superior in vitro and in vivo fungicidal activities and could be a potential fungicidal candidate against plant fungal diseases.


Assuntos
Fungicidas Industriais , Fusarium , Hidroxiquinolinas , Quinolinas , Antifúngicos/farmacologia , Ascomicetos , Botrytis , Fungos , Fungicidas Industriais/farmacologia , Estrutura Molecular , Quinina , Rhizoctonia , Relação Estrutura-Atividade
6.
Int J Mol Sci ; 22(19)2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34638750

RESUMO

Long-term use of a single fungicide increases the resistance risk and causes adverse effects on natural ecosystems. Controlled release formulations of dual fungicides with different modes of action can afford a new dimension for addressing the current issues. Based on adjustable aperture and superhigh surface area, metal-organic frameworks (MOFs) are ideal candidates as pesticide release carriers. This study used Al3+ as the metal node and 2-aminoterephthalic acid as the organic chain to prepare aluminum-based metal-organic framework material (NH2-Al-MIL-101) with "cauliflower-like" structure and high surface area of 2359.0 m2/g. Fungicides of azoxystrobin (AZOX) and diniconazole (Dini) were simultaneously encapsulated into NH2-Al-MIL-101 with the loading content of 6.71% and 29.72%, respectively. Dual fungicide delivery system of AZOX@Dini@NH2-Al-MIL-101 demonstrated sustained and pH responsive release profiles. When the maximum cumulative release rate of AZOX and Dini both reached about 90%, the release time was 46 and 136 h, respectively. Furthermore, EC50 values as well as the percentage of inhibition revealed that AZOX@Dini@NH2-Al-MIL-101 had enhanced germicidal efficacy against rice sheath blight (Rhizoctonia solani), evidenced by the synergistic ratio of 1.83. The present study demonstrates a potential application prospect in sustainable plant protection through co-delivery fungicides with MOFs as a platform.


Assuntos
Fungicidas Industriais , Estruturas Metalorgânicas , Pirimidinas , Rhizoctonia/crescimento & desenvolvimento , Estrobilurinas , Triazóis , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/farmacologia , Fungicidas Industriais/química , Fungicidas Industriais/farmacocinética , Fungicidas Industriais/farmacologia , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/farmacocinética , Estruturas Metalorgânicas/farmacologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Pirimidinas/química , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Estrobilurinas/química , Estrobilurinas/farmacocinética , Estrobilurinas/farmacologia , Triazóis/química , Triazóis/farmacocinética , Triazóis/farmacologia
7.
Sensors (Basel) ; 21(17)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34502763

RESUMO

Electronic noses can be applied as a rapid, cost-effective option for several applications. This paper presents the results of measurements of samples of two pathogenic fungi, Fusarium oxysporum and Rhizoctonia solani, performed using two constructions of a low-cost electronic nose. The first electronic nose used six non-specific Figaro Inc. metal oxide gas sensors. The second one used ten sensors from only two models (TGS 2602 and TGS 2603) operating at different heater voltages. Sets of features describing the shapes of the measurement curves of the sensors' responses when exposed to the odours were extracted. Machine learning classification models using the logistic regression method were created. We demonstrated the possibility of applying the low-cost electronic nose data to differentiate between the two studied species of fungi with acceptable accuracy. Improved classification performance could be obtained, mainly for measurements using TGS 2603 sensors operating at different voltage conditions.


Assuntos
Nariz Eletrônico , Fusarium , Fungos , Rhizoctonia
8.
Zhongguo Zhong Yao Za Zhi ; 46(12): 3102-3105, 2021 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-34467701

RESUMO

Trollius chinensis is a traditional Chinese medicinal material in China, the wild resource of T. chinensis are now exhausted, and commercial medicinal T. chinensis mainly depends on artificial cultivation. As one of the most severely happened diseases at the seedling period, damping off has been a serious threaten to the breeding of T. chinensis seedlings. However, no related research have been reported so far. So, the authors collected damping-off samples of T. chinensis in 2018 from seedling breeding nursery in Guyuan, Hebei province, and carried out study on taxonomic identification of the pathogen. Damping off occurs in the T. chinensis production area from mid-May to late June every year. At the beginning, brown lesions were observed on the basal stem, then the lesions circumferential expanded and constricted, and finally resulted in the fall and death of T. chinensis seedlings. Pathogenic isolate was growing rapidly on the PDA medium, well developed aerial mycelia were grey white at first, then turned brown gradually, and a great number of small dark brown sclerotia were developed in the middle and periphery of the colony. Mycelial diameter of the pathogen was about 7 to 10 µm, near right angle or acute angle branches, near branches with septa, branches and septa with constriction. After the healthy T. chinensis seedlings were inoculated by pathogenic isolate, damping-off was observed soon, and the symptom was as same as those observed in the field. Through homogenous blast, the rDNA-ITS sequence of the pathogenic isolate shown 99.49% to 99.84% homology with Rhizoctonia solani, R. solani AG-1 IC mycelium anastomosis group and Thanatephorus cucumeris, the sexual type of Rhizoctonia. Furthermore, obvious mycelial anastomosis phenomena were observed when the pathogenic isolate and R. solani AG-1 IC strain were confronting cultured. Based on the results above, the pathogenic isolate causing damping off of T. chinensis was identified as R. solani AG-1 IC mycelial anastomosis group. RESULTS:: in the present work have important significance for further research on basic biology of the pathogen and integrated control of damping off causing by it on T. chinensis.


Assuntos
Doenças das Plantas , Plântula , Basidiomycota , Melhoramento Vegetal , Rhizoctonia
9.
J Agric Food Chem ; 69(40): 11781-11793, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34582205

RESUMO

Plant pathogenic fungi seriously affect agricultural production and are difficult to control. The discovery of new leads based on natural products is an important way to innovate fungicides. In this study, 30 natural-product-based magnolol derivatives were synthesized and characterized on the basis of NMR and mass spectroscopy. Bioactivity tests on phytopathogenic fungi (Rhizoctonia solani, Fusarium graminearum, Botrytis cinerea, and Sclerotinia sclerotiorum) in vitro of these compounds were performed systematically. The results showed that 11 compounds were active against four kinds of phytopathogenic fungi with EC50 values in the range of 1.40-20.00 µg/mL, especially compound L5 that exhibited excellent antifungal properties against B. cinerea with an EC50 value of 2.86 µg/mL, approximately 2.8-fold more potent than magnolol (EC50 = 8.13 µg/mL). Moreover, compound L6 showed the highest antifungal activity against F. graminearum and Rhophitulus solani with EC50 values of 4.39 and 1.40 µg/mL, respectively, and compound L7 showed good antifungal activity against S. sclerotiorum. Then, an in vivo experiment of compound L5 against B. cinerea was further investigated in vivo using infected tomatoes (curative effect, 50/200 and 36%/100 µg/mL). The physiological and biochemical studies illustrated that the primary action mechanism of compound L5 on B. cinerea might change the mycelium morphology, increase cell membrane permeability, and destroy the function of mitochondria. Furthermore, structure-activity relationship (SAR) studies revealed that hydroxyl groups play a key role in antifungal activity. To sum up, this study provides a reference for understanding the application of magnolol-based antifungal agents in crop protection.


Assuntos
Antifúngicos , Fungicidas Industriais , Animais , Antifúngicos/farmacologia , Ascomicetos , Compostos de Bifenilo , Botrytis , Fungicidas Industriais/farmacologia , Fusarium , Lignanas , Estrutura Molecular , Rhizoctonia , Relação Estrutura-Atividade
10.
Arch Virol ; 166(11): 3229-3232, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34524536

RESUMO

The complete genome sequence of a double-stranded RNA (dsRNA) virus, Rhizoctonia solani dsRNA virus 11 (RsRV11), isolated from Rhizoctonia solani AG-1 IA strain 9-11 was determined. The RsRV11 genome is 9,555 bp in length and contains three conserved domains: structural maintenance of chromosomes (SMC) superfamily, phosphoribulokinase (PRK), and RNA-dependent RNA polymerase (RdRp). The RsRV11 genome has two non-overlapping open reading frames (ORFs). ORF1 is predicted to encode a 204.12-kDa protein that shares low but significant amino acid sequence similarity with a putative protein encoded by Rhizoctonia solani RNA virus HN008 (RsRV-HN008). ORF2 potentially encodes a 132.41-kDa protein that contains the conserved domain of the RdRp. Phylogenetic analysis indicated that RsRV11 clustered with RsRV-HN008 in a separate clade from other virus families. This implies that RsRV11 and RsRV-HN008 should be included in a new mycovirus taxon close to the family Megabirnaviridae and that RsRV11 is a new mycovirus.


Assuntos
Micovírus/genética , Genoma Viral , Filogenia , Rhizoctonia/virologia , China , Micovírus/isolamento & purificação , Fases de Leitura Aberta , RNA de Cadeia Dupla , Rhizoctonia/isolamento & purificação , Proteínas Virais/genética , Zea mays/microbiologia
11.
J Agric Food Chem ; 69(33): 9557-9570, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34382800

RESUMO

Succinate dehydrogenase inhibitors (SDHIs) have emerged in fungicide markets as one of the fastest-growing categories that are widely applied in agricultural production for crop protection. Currently, the structural modification focusing on the flexible amide link of SDHI molecules is being gradually identified as one of the innovative strategies for developing novel highly efficient and broad-spectrum fungicides. Based on the above structural features, a series of pyrazole-4-acetohydrazide derivatives potentially targeting fungal SDH were constructed and evaluated for their antifungal effects against Rhizoctonia solani, Fusarium graminearum, and Botrytis cinerea. Strikingly, the in vitro EC50 values of constructed pyrazole-4-acetohydrazides 6w against R. solani, 6c against F. graminearum, and 6f against B. cinerea were, respectively, determined as 0.27, 1.94, and 1.93 µg/mL, which were obviously superior to that of boscalid against R. solani (0.94 µg/mL), fluopyram against F. graminearum (9.37 µg/mL), and B. cinerea (1.94 µg/mL). Concurrently, the effects of the substituent steric, electrostatic, hydrophobic, and hydrogen-bond fields on structure-activity relationships were elaborated by the reliable comparative molecular field analysis and comparative molecular similarity index analysis models. Subsequently, the practical value of pyrazole-4-acetohydrazide derivative 6w as a potential SDHI was ascertained by the relative surveys on the in vivo anti-R. solani preventative efficacy, inhibitory effects against fungal SDH, and molecular docking studies. The present results provide an indispensable complement for the structural optimization of antifungal leads potentially targeting SDH.


Assuntos
Fungicidas Industriais , Succinato Desidrogenase , Botrytis , Fungicidas Industriais/farmacologia , Fusarium , Hidrazinas , Simulação de Acoplamento Molecular , Doenças das Plantas , Pirazóis/farmacologia , Relação Quantitativa Estrutura-Atividade , Rhizoctonia , Relação Estrutura-Atividade , Succinato Desidrogenase/metabolismo
12.
J Agric Food Chem ; 69(32): 9461-9471, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34355907

RESUMO

Target identification is one of the most important bases for novel pesticide development; pyruvate kinase (PK) was discovered as a potent fungicide target in our previous studies. To continue the PK-based fungicide development, novel isothiazole-purine derivatives were rationally designed and synthesized. Bioassay results showed that compound 5ai displayed excellent in vitro activity against Rhizoctonia solani with an EC50 of 1.5 µg/mL, which was superior to those of positive controls diflumetorim with its EC50 of 19.8 µg/mL and PK-based lead YZK-C22 with its EC50 of 4.2 µg/mL. Compounds 3b (5.2 µg/mL) and 3c (4.5 µg/mL) displayed better activities against Gibberella zeae with their EC50s falling between 4.0 and 5.5 µg/mL, while YZK-C22 showed an EC50 of 6.4 µg/mL. In addition, 5ah exhibited promising in vivo activity against Erysiphe graminis and Puccinia sorghi Schw. with 100% efficacy at 10 µg/mL and 90% efficacy at 2 µg/mL against P. sorghi Schw. Compound 5ai showed good PK inhibitory activity with an IC50 of 38.8 µmol/L, and it was well docked into the active site of the target enzyme PK, which was slightly more active than YZK-C22 with its IC50 of 42.4 µmol/L. Our studies discovered that isothiazole-purines were PK-based fungicidal leads deserving of further study.


Assuntos
Fungicidas Industriais , Fungicidas Industriais/farmacologia , Fusarium , Chumbo , Purinas , Piruvato Quinase , Rhizoctonia , Relação Estrutura-Atividade
13.
Proc Biol Sci ; 288(1956): 20211313, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34375557

RESUMO

Interactions among parasites and other microbes within hosts can impact disease progression, yet study of such interactions has been mostly limited to pairwise combinations of microbes. Given the diversity of microbes within hosts, indirect interactions among more than two microbial species may also impact disease. To test this hypothesis, we performed inoculation experiments that investigated interactions among two fungal parasites, Rhizoctonia solani and Colletotrichum cereale, and a systemic fungal endophyte, Epichloë coenophiala, within the grass, tall fescue (Lolium arundinaceum). Both direct and indirect interactions impacted disease progression. While the endophyte did not directly influence R. solani disease progression or C. cereale symptom development, the endophyte modified the interaction between the two parasites. The magnitude of the facilitative effect of C. cereale on the growth of R. solani tended to be greater when the endophyte was present. Moreover, this interaction modification strongly affected leaf mortality. For plants lacking the endophyte, parasite co-inoculation did not increase leaf mortality compared to single-parasite inoculations. By contrast, for endophyte-infected plants, parasite co-inoculation increased leaf mortality compared to inoculation with R. solani or C. cereale alone by 1.9 or 4.9 times, respectively. Together, these results show that disease progression can be strongly impacted by indirect interactions among microbial symbionts.


Assuntos
Parasitos , Animais , Colletotrichum , Progressão da Doença , Endófitos , Epichloe , Rhizoctonia
14.
Pestic Biochem Physiol ; 178: 104942, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34446208

RESUMO

Rice sheath blight is a destructive fungal disease caused by Rhizoctonia solani. To find a safe and green measure, the biological activity of six plant extracts against R. solani was determined by mycelial growth rate method. The results showed that magnolol possessed better antifungal activities against R. solani, with an EC50 value of 7.47 mg/L. further action mechanism of magnolol against R. solani was carried out. Studies by scanning electron microscopy (SEM) showed that the morphology of R. solani mycelia was deformation and surface folds. Transmission electron microscope (TEM) observation on treated R. solani showed that magnolol could induce cytoplasmic membrane rupture and cytoplasmic membrane even disappeared completely accompanied with cellular debris was covered around this fungal, and the mycelia treated with magnolol showed fluorescence after PI staining. Further study showed that the content of malondialdehyde (MDA) and activity of chitinase, ß-1,3-glucanase and relative conductivity of mycelia were increased, while the content of soluble protein and activities of catalase (CAT), polyphenol oxidase (PPO), superoxide dismutase (SOD), succinate dehydrogenase (SDH) and NAD-malate dehydrogenase (NAD-MDH) were significantly decreased. These results indicated that magnolol could significantly damage the plasma membrane of R. solani, and interfere with cell respiratory metabolism, thus inhibiting the growth of mycelium.


Assuntos
Doenças das Plantas , Rhizoctonia , Compostos de Bifenilo , Membrana Celular , Lignanas
15.
J Agric Food Chem ; 69(35): 10082-10092, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34432441

RESUMO

Thirty-eight novel ferulic amide 1-aminocyclohexane carboxylic acid (Ac6c) derivatives D1-D19 and E1-E19 were designed and synthesized, and their antibacterial, antifungal, and insecticidal activities were tested. Most of the synthesized compounds displayed excellent activity againstXanthomonas oryzae pv. oryzae (Xoo), with EC50 values ranging from 11.6 to 83.1 µg/mL better than that of commercial bismerthiazol (BMT, EC50 = 84.3 µg/mL), as well as much better performance compared to that of thiediazole copper (TDC, EC50 = 137.8 µg/mL). D6 (EC50 = 17.3 µg/mL), D19 (EC50 = 29.4 µg/mL), E3 (EC50 = 29.7 µg/mL), E9 (EC50 = 27.0 µg/mL), E10 (EC50 = 18.6 µg/mL), and E18 (EC50 = 20.8 µg/mL) showed much higher activity on Xanthomonas oryzae pv. oryzicola compared with BMT (EC50 = 80.1 µg/mL) and TDC (EC50 = 124.7 µg/mL). In relation to controlling the fungus, Rhizoctonia solani, E1, E10, and E13 had much lower EC50 values of 0.005, 0.140, and 0.159 µg/mL compared to hymexazol at 74.8 µg/mL. Further in vivo experiments demonstrated that E6 and E12 controlled rice bacterial leaf blight disease better than BMT and TDC did. Scanning electron microscopy (SEM) studies revealed that E12 induced the Xoo cell membrane collapse. Moreover, D13 (73.7%), E5 (80.6%), and E10 (73.4%) also showed moderate activity against Plutella xylostella. These results indicated that the synthesized ferulic amide Ac6c derivatives showed promise as candidates for treating crop diseases.


Assuntos
Oryza , Xanthomonas , Amidas/farmacologia , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Oxidiazóis , Doenças das Plantas , Rhizoctonia
16.
Appl Microbiol Biotechnol ; 105(13): 5517-5528, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34250572

RESUMO

Xenorhabdus and Photorhabdus spp. are enteric bacterial symbionts of Steinernema and Heterorhabditis nematodes, respectively. These bacteria produce an extensive set of natural products (NPs) with antibacterial, antifungal, antiprotozoal, insecticidal, or other bioactivities when vectored into insect hemocoel by nematodes. We assessed the in vitro activity of different Xenorhabdus and Photorhabdus cell-free supernatants against important fungal phytopathogens, viz., Cryphonectria parasitica, Fusarium oxysporum, Rhizoctonia solani, and Sclerotinia sclerotiorum and identified the bioactive antifungal compound/s present in the most effective bacterial supernatant using the easyPACId (easy promoter-activated compound identification) approach against chestnut blight C. parasitica. Our data showed that supernatants from Xenorhabdus species were comparatively more effective than extracts from Photorhabdus in suppressing the fungal pathogens; among the bacteria assessed, Xenorhabdus szentirmaii was the most effective species against all tested phytopathogens especially against C. parasitica. Subsequent analysis revealed fabclavines as antifungal bioactive compounds in X. szentirmaii, generated by a polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) hybrid system. Fabclavines are broad-spectrum, heat-stable NPs that have great potential as biological control compounds against fungal plant pathogens. More studies are needed to assess the potential phytotoxicity of these compounds and their effects on non-target organisms before commercialization. KEY POINTS: • Chemical fungicides have toxic effects on humans and other non-target organisms. • Alternatives with novel modes of action to supplant current fungicide are needed. • A novel bioactive antifungal compound from Xenorhabdus szentirmaii was identified.


Assuntos
Photorhabdus , Xenorhabdus , Animais , Antifúngicos/farmacologia , Ascomicetos , Fusarium , Humanos , Doenças das Plantas , Rhizoctonia , Simbiose
17.
Molecules ; 26(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202103

RESUMO

Eight novel pyridyl-oxazole carboxamides were evaluated against fungi and displayed good fungicidal activities against Botrytis cinereal and Rhizoctonia solani. Preliminary bioassay results indicated that at 100 mg/L, compounds 6a-6e, 6g and 6h exhibited 100% fungicidal activities against Botrytis cinerea, and the compound 6b to Rhizoctonia solani at 100%. Then, the zebrafish embryo acute toxicity test was performed to assess the toxicity of 6b and 6c. A series of malformations appeared, when the zebrafish embryos were exposed to 6b and 6c, such as delayed yolk sac resorption, significant shortening of body length, pericardial edema, bending spine, lack of melanin, heart hemorrhage, head hemorrhage, delayed swim sac development, yolk malformation and head malformation. In addition, the acute toxicity of 6b to zebrafish embryo is 4.878 mg/L, and 6c is 6.257 mg/L.


Assuntos
Antifúngicos , Botrytis/crescimento & desenvolvimento , Embrião não Mamífero/embriologia , Imidazóis , Rhizoctonia/crescimento & desenvolvimento , Peixe-Zebra/embriologia , Animais , Antifúngicos/efeitos adversos , Antifúngicos/química , Antifúngicos/farmacologia , Imidazóis/efeitos adversos , Imidazóis/química , Imidazóis/farmacologia
18.
J Agric Food Chem ; 69(30): 8347-8357, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34288693

RESUMO

Inspired by natural 2-quinolinecarboxylic acid derivatives, a series of quinoline compounds containing acylhydrazine, acylhydrazone, sulfonylhydrazine, oxadiazole, thiadiazole, or triazole moieties were synthesized and evaluated for their fungicidal activity. Most of these compounds exhibited excellent fungicidal activity in vitro. Significantly, compound 2e displayed the superior in vitro antifungal activity against Sclerotinia sclerotiorum, Rhizoctonia solani, Botrytis cinerea, and Fusarium graminearum with the EC50 values of 0.39, 0.46, 0.19, and 0.18 µg/mL, respectively, and were more potent than those of carbendazim (EC50, 0.68, 0.14, >100, and 0.65 µg/mL, respectively). Moreover, compound 2e could inhibit spore germination of F. graminearum. Preliminary mechanistic studies showed that compound 2e could cause abnormal morphology of cell walls and vacuoles, loss of mitochondrion, increases in membrane permeability, and release of cellular contents. These results indicate that compound 2e displayed superior fungicidal activities and could be a potential fungicidal candidate against plant fungal diseases.


Assuntos
Fungicidas Industriais , Quinolinas , Antifúngicos/farmacologia , Ascomicetos , Botrytis , Fungicidas Industriais/farmacologia , Fusarium , Estrutura Molecular , Quinolinas/farmacologia , Rhizoctonia , Relação Estrutura-Atividade
19.
J Agric Food Chem ; 69(30): 8380-8393, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34296859

RESUMO

Developing multipurpose agricultural chemicals is appealing in crop protection, thus eventually realizing the reduction and efficient usage of pesticides. Herein, an array of versatile pyrazole hydrazide derivatives bearing a 1,3,4-oxadiazole core were initially synthesized and biologically evaluated the antifungal, antioomycetes, and antibacterial activities. In addition, the pyrazole ring was replaced by the correlative pyrrole, thiazole, and indole scaffolds to extend the molecular diversity. The results showed that most of these hybrid compounds were empowered with multifunctional bioactivities, which are exemplified by compounds a1-a6, b1-b3, b7, b10, b13, and b18. For the antifungal activity, the minimal EC50 values could afford 0.47 (a2), 1.05 (a2), 0.65 (a1), and 1.32 µg/mL (b3) against the corresponding fungi Gibberella zeae (G. z.), Fusarium oxysporum, Botryosphaeria dothidea, and Rhizoctonia solani. In vivo pot experiments against corn scab (caused by G. z.) revealed that the compound a2 was effective with protective and curative activities of 90.2 and 86.3% at 200 µg/mL, which was comparable to those of fungicides boscalid and fluopyram. Further molecular docking study and enzymatic activity analysis (IC50 = 3.21 µM, a2) indicated that target compounds were promising succinate dehydrogenase inhibitors. Additionally, compounds b2 and a4 yielded superior anti-oomycete and antibacterial activities toward Phytophora infestins and Xanthomonas oryzae pv. oryzae with EC50 values of 2.92 and 8.43 µg/mL, respectively. In vivo trials against rice bacterial blight provided the control efficiency within 51.2-55.3% (a4) at 200 µg/mL, which were better than that of bismerthiazol. Given their multipurpose characteristics, these structures should be positively explored as agricultural chemicals.


Assuntos
Infecções Bacterianas , Oomicetos , Xanthomonas , Agroquímicos , Antibacterianos/farmacologia , Ascomicetos , Fusarium , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Oxidiazóis , Doenças das Plantas , Pirazóis/farmacologia , Rhizoctonia , Relação Estrutura-Atividade
20.
Ecotoxicol Environ Saf ; 222: 112534, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34311429

RESUMO

Penflufen fungicide is widely used as a racemate, which has potential ecological risks to aquatic organisms, while its enantioselective toxicity data is limited. This study aimed to differentiate the enantioselective toxicity difference of penflufen enantiomers, and illuminate the enantioselective mechanism from the insight of enantiomer-protein specific binding. The semipreparative separation and absolute configuration of penflufen enantiomers were conducted. The acute toxicity of S-(+)-penflufen was 54 times higher than R-(-)-penflufen to Danio rerio, and the coexistence of R-(-)-penflufen could increase the exposure risk of S-(+)-penflufen. For chronic toxicity, after low-dose long-term exposure, rac-penflufen and S-(+)-penflufen inducted more serious oxidative stress than R-(-)-penflufen in D. rerio, and inhibited the succinate dehydrogenase (SDH) activity significantly. For target phytopathogen, the toxicity difference of S-(+)-penflufen and R-(-)-penflufen was up to 148 times for Rhizoctonia solani. Based on the toxic unit analysis, the toxic interactions of antagonistic effect and concentration addition were found between penflufen enantiomers, indicating the coexistence of R-(-)-penflufen could increase overuse and environmental risks. Computational chemistry was used to illuminate the enantioselectivity mechanism, and the lower binding energy between the active site of SDH and S-(+)-penflufen contributed to the higher toxicity. The higher target toxicity might be due to the hydrophobic pocket of CybL in R. solani was more benefited to S-(+)-penflufen binding SDH than Botrytis cinerea. These results could be helpful for further understanding the potential risk of chiral penflufen in the environment, demonstrating the importance of understanding the enantioselective difference of chiral pesticides, and providing a new insight for analyzing the enantioselective mechanism.


Assuntos
Fungicidas Industriais , Anilidas , Botrytis , Química Computacional , Fungicidas Industriais/toxicidade , Rhizoctonia , Estereoisomerismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...