Maize(Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and s...Maize(Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues. Given favourable environmental conditions, this disease spread to areas surrounding Gansu. In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018and 2020 to identify the disease-causing pathogen. Based on morphological features, pathogenicity tests, and multilocus phylogenetic analysis involving internal transcribed spacer(ITS), 18S small subunit rDNA(SSU), 28S large subunit rDNA(LSU), translation elongation factor 1-alpha(TEF), and β-tubulin(TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight. Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis. The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight.展开更多
Chinese chive is a kind of medicinal and edible plant,with many diseases,and chemical fungicides are usually used for control.In order to find out the risk of pesticide residues in Chinese chives,this paper summarized...Chinese chive is a kind of medicinal and edible plant,with many diseases,and chemical fungicides are usually used for control.In order to find out the risk of pesticide residues in Chinese chives,this paper summarized relevant literatures published in recent years,and sorted out and analyzed the types of pesticides used and detection techniques of common diseases in Chinese chives.展开更多
Fusarium head blight(FHB) caused by Fusarium graminearum is a devastating fungal disease on small grain cereal crops,because it reduces yield and quality and causes the mycotoxin contamination to the grain.Dynamins an...Fusarium head blight(FHB) caused by Fusarium graminearum is a devastating fungal disease on small grain cereal crops,because it reduces yield and quality and causes the mycotoxin contamination to the grain.Dynamins and dynamin-related proteins(DRPs) are large GTPase superfamily members,which are typically involved in the budding and division of vesicles in eukaryotic cells,but their roles in Fusarium spp.remain unexplored.Here,we found that FgDnm1,a DRP and homolog to Dnm1 in Saccharomyces cerevisiae,contributes to the normal fungal growth,sexual reproduction and sensitivity to fungicides.In addition,we found FgDnm1 co-localizes with mitochondria and is involved in toxisome formation and deoxynivalenol(DON) production.Several quinone outside inhibitors(QoIs) and succinate dehydrogenase inhibitors(SDHIs) cause fragmentated morphology of mitochondria.Importantly,the deletion of FgDnm1displays filamentous mitochondria and blocks the mitochondrial fragmentation induced by QoIs and SDHIs.Taken together,our studies uncover the effect of mitochondrial dynamics in fungal normal growth and how such events link to fungicides sensitivity and toxisome formation.Thus,we concluded that altered mitochondrial morphology induced by QoIs and SDHIs depends on FgDnm1.展开更多
MicroRNAs(miRNAs)are small noncoding RNA molecules ubiquitously distributed across diverse organisms,serving as pivotal regulators of genetic expression.Notably,plant-derived miRNAs have been demonstrated to have uniq...MicroRNAs(miRNAs)are small noncoding RNA molecules ubiquitously distributed across diverse organisms,serving as pivotal regulators of genetic expression.Notably,plant-derived miRNAs have been demonstrated to have unique bioactivity and certain stability in mammalian systems,thereby facilitating their capacity for cross-kingdom modulation of gene expression.While there is substantial evidence supporting the regulation of mammalian cells by plant-derived miRNAs,several questions remain unanswered.Specifically,a comprehensive investigation of the mechanisms underlying the stability and transport of plant miRNAs and their cross-kingdom regulation of gene expression in mammals remains to be done.In this review,we summarized the origin,processing,and functional mechanisms of plant miRNAs in mammalian tissues and circulation,emphasizing their greater resistance to mammalian digestion and circulation systems compared to animal miRNAs.Additionally,we introduce four well-known plant miRNAs that have been extensively studied for their functions and mechanisms in mammalian systems.By delving into these aspects,we aim to offer a fundamental understanding of this intriguing field and shed light on the complex interactions between plant miRNAs and mammalian biology.展开更多
Leaf and fruit spot (Pseudocercospora angolensis) disease of citrus attacks leaves, fruits, and young twigs of the plant. The disease can cause a yield loss of (50% to 100%) in areas with high rainfall and humidity du...Leaf and fruit spot (Pseudocercospora angolensis) disease of citrus attacks leaves, fruits, and young twigs of the plant. The disease can cause a yield loss of (50% to 100%) in areas with high rainfall and humidity during the active growth stages of the crop. Currently, citrus plantations in the south, south-west and north-west of Ethiopia are seriously affected by this disease. As a result, this study was proposed to study the effect of fungicides in controlling. And candidate fungicides were: Carbonchlor 50% SC only, Benline 50% WP only, Bellis 38% WG only, Carbonchlor 50% SC combined with Bellis 38% WG, Benline 50% WP combined with Carbonchlor 50% SC and Benline 50% WP combined with Matco 72% WP for effective management of citrus leaf and fruit spot (Pseudocercospra angolensis) disease. The study was carried out in 2021 cropping season. A Randomized Complete Block Design (RCBD) with three replications was the design applied. The result showed that the highest level of efficacy (90.46%) was produced by Bellis 38% WG fungicide followed by Carbonchlor 50% SC (86.50%), Bellis 38% WG + Carbonchlor 50% SC (82.00%), Carbonchlor 50% SC + Benline 50% WP (67.89%), Benline 50% WP (65.62%) and Matco 72% WP + Benline 50% WP (49.48%). Therefore, based on the outcome of the study application of Bellis 38% WG only followed by Carbonchlor 50% SC only, Carbonchlor 50% SC combined with Benline 50% WP, Bellis 38% WG combined with Carbonchlor 50% SC, Bellis 38% WG only, Benline 50% WP only and Matco 72% WP combined with Benline 50% WP were effective fungicides to be used for the control of leaf and fruit spot disease.展开更多
Potato propagation through tubers and seed is an inefficient way of propagation thus we propose an alternative method in this study which is in vitro propagation.Plantlets were raised from True Potato Seeds(TPS)in test...Potato propagation through tubers and seed is an inefficient way of propagation thus we propose an alternative method in this study which is in vitro propagation.Plantlets were raised from True Potato Seeds(TPS)in test tubes containing 10 mL of Murashige Skoog(MS)medium.Subculturing was done after every 21 days and after four subsequent subculturing,when there was an adequate quantity of stock material,uninodal cuttings of about 3-4 mm in length were prepared from in vitro proliferated potato plants by excising leaves of 1-2 mm on each side of the node.Prepared uninodal cuttings were cultured on 1/2 strength MS medium for root primordia development.The selected uninodal cuttings with root primordia were encapsulated with sodium alginate solution(3.5%(w/v)),mixed with 1.25%charcoal and different concentration of fungicide(thiophanate methyl,sigma)to enhance the viability percentage of synthetic seed.Furthermore,these encapsulated uninodal cuttings were subjected to different storage intervals to check maximum storage.Results showed that optimum dose for fungicide is 150 mg/L as it resulted in good viability percentage,shoot number,shoot length,rooting percentage,root number,root length and ideal for bead formation with sodium alginate.Similarly,results revealed that encapsulated uninodal cuttings can be stored at a temperature of 4℃ up to 45 days with a survival rate of 63.33%.Encapsulated uninodal cutting stored for 60 days showed a poor viability percentage of about 43.03%.It can be concluded that optimum dose of 150 mg/L with storage time of 45 days should be used to get a better outcome for synthetic potato seed production.展开更多
[Objectives]The paper was to identify the characteristics and the potency of new fungicides to rice blast disease,and study their preventive and therapeutic effects on the disease.[Methods]Six new and conventional fun...[Objectives]The paper was to identify the characteristics and the potency of new fungicides to rice blast disease,and study their preventive and therapeutic effects on the disease.[Methods]Six new and conventional fungicides with different mechanisms of action were selected to compare their preventive and therapeutic effects on rice seedling blast in greenhouse.[Results]The agents which showed to be highly efficacious in blast prevention(greater than 90%)were 25%pyraclostrobin EC,20%fenoxanil SC,75%tricyclazole WP and 50%prochloraz-manganese WP sprayed at the dosages of 112.5-150,180-360,270-450 and 450-600 g/ha,respectively.The therapeutic effect of new fungicides 25%pyraclostrobin EC and 50%prochloraz-manganese WP on rice blast were above 90%when the dosages were 90-150 and 360-600 g/ha,respectively.The therapeutic effect of the conventional fungicide 40%isoprothiolane EC on rice blast was 69.04%when the dosage was 480 g/ha,while those of other fungicides were worse.[Conclusions]Both 25%pyraclostrobin EC and 50%prochloraz-manganese WP have good preventive and therapeutic effects on rice blast,which will provide a reference for the use of these fungicides in the field.展开更多
Natural antiseptic formulas are increasingly favored by consumers. This article take preservatives compounded from cinnamon, sophora flavescens and other plant extracts as the main research object, evaluated its antib...Natural antiseptic formulas are increasingly favored by consumers. This article take preservatives compounded from cinnamon, sophora flavescens and other plant extracts as the main research object, evaluated its antibacterial efficacy and application in cosmetics, expect that it can be used in cosmetics to replace conventional chemical preservatives. Research on its antibacterial efficacy through inhibition zone and MIC experiment, and product application research used anti-corrosion challenge and antibacterial rate experiment. The results showed that the plant-derived antiseptic system had a broad antibacterial spectrum, inhibition of 10 different common pathogenic bacteria, and had a very significant inhibitory effect on Gram-positive bacteria and fungi;Among them, the diameter of the antibacterial circle for Bacillus subtilis and Aspergillus niger can reached 31.89 mm and 28.26 mm, while the MIC value was 0.4 mg/mL and 0.8 mg/mL. The spray product with 1.5% addition amount successfully passed the anti-corrosion challenge test and meets the anti-corrosion standard requirements;The 2% added amount of disposable gel product has an inhibitory rate of 51.05% and 70.74% against Escherichia coli and Staphylococcus aureus within 20 minutes of action. In summary, the plantderived compound preservative has ability to be used in cosmetic preservative systems.展开更多
This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in ...This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in controlling Fusarium head blight (FHB) on wheat and other cereals. The mode of action of JS399-19 is evidently different from that of benzimidazole (for example, carbendazim) and other sort of fungicides, making it a possible replacement for carbendazim in China to manage carbendazim-resistant subpopulations of Fusarium graminearum and F. asiaticum. JS399-t9 has excellent protective and curative activity against these pathogens. Incorrect use of this fungicide, however, is likely to select for resistance. Among JS399-19-resistant mutants of F. asiaticum induced in the laboratory, the resistant level of mutants was high and the phenotype of resistance against JS399-19 was conferred by a major gene by genetic analysis. The fitness of laboratory-induced JS399-19-resistant mutants of F. asiaticum was nearly equal to that of their parents. JS399-19 lacks cross resistance with other sort fungicides. To control FHB with JS399-19 and to delay the development of the fungicide-resistance, farmers should use tank mixtures containing JS399-19 and carbendazim, metconazole, tebuconazole, or prothioconazole.展开更多
Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere....Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.展开更多
Nanotechnologies have been successfully applied to the treatment of various diseases.Plant-derived exosome-like nanoparticles (PENs) are expected to become effective therapeutic modalities for treating disease or in d...Nanotechnologies have been successfully applied to the treatment of various diseases.Plant-derived exosome-like nanoparticles (PENs) are expected to become effective therapeutic modalities for treating disease or in drug-delivery. PENs are minimally cytotoxic to healthy tissues, with which they show excellent biocompatibility, and are biased towards tumors by targeting specific tissues through special endocytosis mechanisms. Thus, the use of these PENs may expand the scope of drug therapies while reducing the off-target effects.In this review, we summarize the fundamental features and bioactivities of PENs extracted from the grape, grapefruit, ginger, lemon, and broccoli and discuss the applications of these particles as therapeutics and nanocarriers.展开更多
The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botryt...The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botrytis cinerea of strawberry in vitro, in vivo and in greenhouse were studied. The pathogen B. cinerea was more affected in vitro by low concentrations of the fungicides tested above 0.4 μg·ml-1 than the bioagent T. harzianum (Jn14). The later was almost insensitive to pyrimethanil. In the same direction, gray mould disease severity on strawberry detached leaves and whole plants was reduced up to 89% by the tested fungicides, compared to the control, while the application of T. harzianum (Jn14) alone reduced disease severity up to 45% on strawberry detached leaves, compared to the control. In the integrated control approach, the combination of T. harzianum (Jn14) with higher concentrations of the tested fungicides (ED50) completely inhibited strawberry gray mould disease severity in pots and the greenhouse.展开更多
Two seed lots of lettuce (Lactuca sativa L.) cv. Krlowa Majowych were primed in polyethylene glycol (PEG) 8000 at -1.25MPa for 7 days in dark at 20C. Two fungicide treatments combined with PEG were used to control fun...Two seed lots of lettuce (Lactuca sativa L.) cv. Krlowa Majowych were primed in polyethylene glycol (PEG) 8000 at -1.25MPa for 7 days in dark at 20C. Two fungicide treatments combined with PEG were used to control fungi: 1) Funaben T(0.1%) and Apron 35 SD (0.02%) were added to -1.25 MPa PEG solution (PEG+F); 2) After seed priming and drying,Funaben T was mixed at 5 g kg-1 and Apron 35 SD at 1 g kg-1 of seeds (PEG then F dust). PEG, PEG+F and PEG then F dusttreatments reduced significantly thermodormancy and increased the seed germination at 35C in both lots. PEG then Fdust treatment had the best effect on reducing seed thermodormancy at 35C, and increased seed germination to 64.5% inlot 1 and 72.0% in lot 2 compared to 0 in untreated. PEG and PEG then F dust treatments have accelerated germinationspeed at 20 and 15C in both lots. There was a significant reduction in seed infestation in which the seeds were treatedwith PEG+F and PEG then F dust compared to untreated seeds and PEG primed seeds. PEG priming enhanced seedinfestation considerably by Alternaria alternata, Penicillium spp., Rhizopus spp. and Ulocladium spp. Mycologicalanalysis showed higher frequency of Alternaria alternata and Ulocladium spp. in untreated seeds at 20C. Priming incombination with fungicides significantly alleviated the infestation of fungi, especially Alternaria alternata infestation.展开更多
In this research,the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among t...In this research,the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among the 16 tested fungicides,10% of Difenoconazole WG,33. 5% of Copper quinolate SC,25%of Bromothalonil EC,70% of Mancozeb WP,430 g/L of Tebuconazole SC,50% of Prochloraz-manganese chloride and 400 g/L of Flusilazole EC achieved the best inhibitory effect on mycelial growth of C. horri,with the inhibition rate of 100%; 70% of Polyram WG,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP,50% of Chlorobromoisocyanuric acid AF,50% of Triram WP and 400 g/L of Flusilazole achieved the best inhibitory effect on spore germination of C. horri,with the germination rate of 0. In conclusion,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP and 400 g/L of Flusilazole EC achieved the best inhibitory effect both in mycelial growth and spore germination,which could be used as the preference fungicides for the control of persimmon anthracnose,and 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect,which could be used as alternative fungicides. The results of this research could provide scientific evidence for the effective control of persimmon anthracnose,and more optional pesticides for utilization in the production practice of persimmon industry.展开更多
The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their ant...The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their antagonistic ability to Penicilliumexpansumand Alternariaalternata in vitro when applied with fungicide. There were significantdifferences in sensitivity to the fungicides among the different yeasts(P=0.05). R.glutinis was more sensitive to Deccocil, Iprodione and Stroby as compared to otheryeasts. Combination antagonistic yeasts with fungicide could more significantly enhancebiocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05). C.laurentii was the most effective antagonist among the four yeasts and could completelycontrol spore germination of P.expansum and A.alternata when combined with Stroby at theconcentration of 100 L L-1. The yeasts, except R.glutinis, could grow well on nutrientyeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp. showeda better adaptability to low temperature as comparedto other antagonists.展开更多
Wheat blast, caused by a fungal pathogen, <i><span style="font-family:Verdana;">Magnaporthe oryzae Tritichum </span></i><span style="font-family:Verdana;">(</span&g...Wheat blast, caused by a fungal pathogen, <i><span style="font-family:Verdana;">Magnaporthe oryzae Tritichum </span></i><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">MoT</span></i><span style="font-family:Verdana;">) pathotype (wheat isolates), was first reported in Bangladesh among Asian countries in 2016. It is a serious disease of wheat causing yield failures and significant economic losses during epidemic years. Extensive use of persistent synthetic pesticides to control notorious wheat blast imposes enormous threat to human health and environment. In addition, the increasing demand for organic food has stimulated people to look for alternative methods. Nowadays, the need for synthetic chemical-free agricultural practices is gaining importance due to effective in managing crop pests, inexpensive, biodegradable, easily available and have low toxicity to non-target organisms. In order to identify active plants, 12 kinds of methanol extracts obtained from 12 medicinal plants were conducted </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> to test the effect against </span><i><span style="font-family:Verdana;">Magnaporthe oryzae Triticum </span></i><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">MoT</span></i><span style="font-family:Verdana;">) pathotype. The remarkable inhibitory activity {(29.6 ± 01.5) mm, (25.1 ± 01.0) mm and (20.0 ± 02.0) mm zone of inhibition)} exhibited by the extracts (5 mg/disk) obtained from </span><i><span style="font-family:Verdana;">Artemisia indica</span></i><span style="font-family:Verdana;"> (Nagdona), </span><i><span style="font-family:Verdana;">Persicaria orientalis</span></i><span style="font-family:Verdana;"> (Bishkatali) and </span><i><span style="font-family:Verdana;">Clerodendrum indicum</span></i><span style="font-family:Verdana;"> (Bamonhati), respectively. Other medicinal plant extracts did not show any significant or no activity at all. Therefore, the three plant extracts might be a promising source for developing natural fungicides against wheat blast.</span>展开更多
Tolerance in isolations of Trichoderma was developed by exposing two strains of T. harzianum and three of T. asperelloides to increasing concentrations of chemical fungicides. These isolation of Trichoderma were expos...Tolerance in isolations of Trichoderma was developed by exposing two strains of T. harzianum and three of T. asperelloides to increasing concentrations of chemical fungicides. These isolation of Trichoderma were exposed to three fungicides: Captan, Thiabendazol and the mixture Captan-Carboxin. Some selected lines of these strains reached tolerance to Captan and partial tolerance to the mixture Captan-Carboxin. The biological and genetic changes in these tolerant lines were monitored by determining the relative growth rate of the fungus, inhibition of Fusarium and by analyzing the genomic changes through UP-PCR. The results show that the tolerance to fungicides can be developed without affecting the parameters of biological activity in these lines of Trichoderma (growth and parasitism against Fusarium). Chemical tolerance to the fungicide was verified by means of changes at the DNA level (UP-PCR), mainly in the lines tolerant to Captan. This suggests that Trichoderma survives in environments with remnants of fungicide molecules.展开更多
There are few kinds of fungicides for the prevention and treatment of Rhizoctonia solani,and the excessive use of chemical fungicides can cause many hazards and toxic and side effects,not in line with the requirements...There are few kinds of fungicides for the prevention and treatment of Rhizoctonia solani,and the excessive use of chemical fungicides can cause many hazards and toxic and side effects,not in line with the requirements of rice planting. The mixed use of wood vinegar and chemical fungicides can reduce the use of chemical fungicides,alleviate pollution and improve rice quality. In this experiment,the Horsfall method was used to study the synergistic inhibiting effect of mixture between wood vinegar and chemical fungicides on the growth of Rhizoctonia solani,as well as the optimal ratio. The results showed that when wood vinegar was mixed with Captan,the synergistic mixture ratio was 4∶6,3∶ 7 or 1∶ 9,and the toxicity ratio under mixture ratio of 4∶ 6 and 1∶ 9 was 1. 75 and 1. 99,respectively,with significant synergistic effect;when wood vinegar was mixed with Chlorothalonil,the toxicity ratio(1. 08) under mixture ratio of 8∶ 2 was greater than 1,showing additive effect.展开更多
The morphophysiological and molecular-genetic parameters of T. caries isolates collected from various fields of Southern Urals agrocenoses have been analysed. Isolate 1 of wheat callus had a high growth rate in vitro ...The morphophysiological and molecular-genetic parameters of T. caries isolates collected from various fields of Southern Urals agrocenoses have been analysed. Isolate 1 of wheat callus had a high growth rate in vitro even in the presence of 0.1 mg/l fungicide Baitan. Isolate 2 of wheat callus had a low growth rate whereas 0.1 mg/l Baitan significantly inhibited its growth. Comparison of nucleotide sequences of 18S RNA gene of the two isolates showed high level of homology between them, but a large number of nucleotide substitutions have been found. The most characteristic excision was five nucleotides at position 461 of the isolate 2, compared with the isolate 1. Our results allow to assume that the environmental stress including high pesticide concentration may cause the resistance of T. caries pathogen to fungicides.展开更多
Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study ...Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study was to assess the feasibility of using fluazinam to treat tobacco black shank disease.In vitro toxicities of fluazinam to 62 isolates of P.nicotianae were determined by mycelial growth rate method.The EC50 values ranged from 0.294 6 to 2.389 9 μg/mL with a mean of 1.084 0 μg/mL.The sensitivity distribution was unimodal,and there was no resistant isolate in P.nicotianae population.The carboxylic acid amide(CAA)fungicides were single-site in action and activity to oomycetes.The synergistic interactions were tested by Wadley method between fluazinam and dimethomorph,flumorph,mandipropamid,respectively.The mixture containing dimethomoph:Huazinam at 1:2 ratio showed additive actions,with the synergy ratio of 1.2.The mixture containing flumorph and fluazinam at 1:5 ratio had the highest synergy ratio(SR 2.07).Mandipropamid and fluazinam had an additive interaction and the proportion of 2:1 had the lowest EC50 value(0.020 7 μg/mL).This study demonstrated the sensitivity of P.nicotianae to fluazinam,and provided the experimental foundation to use fluazinam for tobacco black shank management.展开更多
基金supported by the Doctor Foundation of Gansu Academy of Agricultural Sciences,China(2020GAAS33)the Young Science and Technology Lifting Engineering Talents in Gansu Province,China(2020-18)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2017-ICS)。
文摘Maize(Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues. Given favourable environmental conditions, this disease spread to areas surrounding Gansu. In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018and 2020 to identify the disease-causing pathogen. Based on morphological features, pathogenicity tests, and multilocus phylogenetic analysis involving internal transcribed spacer(ITS), 18S small subunit rDNA(SSU), 28S large subunit rDNA(LSU), translation elongation factor 1-alpha(TEF), and β-tubulin(TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight. Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis. The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight.
基金Supported by Special Project of the Central Government in Guidance of Local Science and Technology Development (Scientific and Technological Innovation Base Project) (226Z5504G)The Fourth Batch of High-end Talent Project in Hebei Province.
文摘Chinese chive is a kind of medicinal and edible plant,with many diseases,and chemical fungicides are usually used for control.In order to find out the risk of pesticide residues in Chinese chives,this paper summarized relevant literatures published in recent years,and sorted out and analyzed the types of pesticides used and detection techniques of common diseases in Chinese chives.
基金supported by the National Natural Science Foundation of China (31772190)the Jiangsu Agriculture Science and Technology Innovation Fund, China (JASTIF) (CX(21)2037)the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (KYCX21_0631)。
文摘Fusarium head blight(FHB) caused by Fusarium graminearum is a devastating fungal disease on small grain cereal crops,because it reduces yield and quality and causes the mycotoxin contamination to the grain.Dynamins and dynamin-related proteins(DRPs) are large GTPase superfamily members,which are typically involved in the budding and division of vesicles in eukaryotic cells,but their roles in Fusarium spp.remain unexplored.Here,we found that FgDnm1,a DRP and homolog to Dnm1 in Saccharomyces cerevisiae,contributes to the normal fungal growth,sexual reproduction and sensitivity to fungicides.In addition,we found FgDnm1 co-localizes with mitochondria and is involved in toxisome formation and deoxynivalenol(DON) production.Several quinone outside inhibitors(QoIs) and succinate dehydrogenase inhibitors(SDHIs) cause fragmentated morphology of mitochondria.Importantly,the deletion of FgDnm1displays filamentous mitochondria and blocks the mitochondrial fragmentation induced by QoIs and SDHIs.Taken together,our studies uncover the effect of mitochondrial dynamics in fungal normal growth and how such events link to fungicides sensitivity and toxisome formation.Thus,we concluded that altered mitochondrial morphology induced by QoIs and SDHIs depends on FgDnm1.
基金supported by grants from the Ministry of Science and Technology of the People’s Republic of China(2018YFA0507101,2021YFA1300301)the Beijing Natural Science Foundation(5215016)。
文摘MicroRNAs(miRNAs)are small noncoding RNA molecules ubiquitously distributed across diverse organisms,serving as pivotal regulators of genetic expression.Notably,plant-derived miRNAs have been demonstrated to have unique bioactivity and certain stability in mammalian systems,thereby facilitating their capacity for cross-kingdom modulation of gene expression.While there is substantial evidence supporting the regulation of mammalian cells by plant-derived miRNAs,several questions remain unanswered.Specifically,a comprehensive investigation of the mechanisms underlying the stability and transport of plant miRNAs and their cross-kingdom regulation of gene expression in mammals remains to be done.In this review,we summarized the origin,processing,and functional mechanisms of plant miRNAs in mammalian tissues and circulation,emphasizing their greater resistance to mammalian digestion and circulation systems compared to animal miRNAs.Additionally,we introduce four well-known plant miRNAs that have been extensively studied for their functions and mechanisms in mammalian systems.By delving into these aspects,we aim to offer a fundamental understanding of this intriguing field and shed light on the complex interactions between plant miRNAs and mammalian biology.
文摘Leaf and fruit spot (Pseudocercospora angolensis) disease of citrus attacks leaves, fruits, and young twigs of the plant. The disease can cause a yield loss of (50% to 100%) in areas with high rainfall and humidity during the active growth stages of the crop. Currently, citrus plantations in the south, south-west and north-west of Ethiopia are seriously affected by this disease. As a result, this study was proposed to study the effect of fungicides in controlling. And candidate fungicides were: Carbonchlor 50% SC only, Benline 50% WP only, Bellis 38% WG only, Carbonchlor 50% SC combined with Bellis 38% WG, Benline 50% WP combined with Carbonchlor 50% SC and Benline 50% WP combined with Matco 72% WP for effective management of citrus leaf and fruit spot (Pseudocercospra angolensis) disease. The study was carried out in 2021 cropping season. A Randomized Complete Block Design (RCBD) with three replications was the design applied. The result showed that the highest level of efficacy (90.46%) was produced by Bellis 38% WG fungicide followed by Carbonchlor 50% SC (86.50%), Bellis 38% WG + Carbonchlor 50% SC (82.00%), Carbonchlor 50% SC + Benline 50% WP (67.89%), Benline 50% WP (65.62%) and Matco 72% WP + Benline 50% WP (49.48%). Therefore, based on the outcome of the study application of Bellis 38% WG only followed by Carbonchlor 50% SC only, Carbonchlor 50% SC combined with Benline 50% WP, Bellis 38% WG combined with Carbonchlor 50% SC, Bellis 38% WG only, Benline 50% WP only and Matco 72% WP combined with Benline 50% WP were effective fungicides to be used for the control of leaf and fruit spot disease.
文摘Potato propagation through tubers and seed is an inefficient way of propagation thus we propose an alternative method in this study which is in vitro propagation.Plantlets were raised from True Potato Seeds(TPS)in test tubes containing 10 mL of Murashige Skoog(MS)medium.Subculturing was done after every 21 days and after four subsequent subculturing,when there was an adequate quantity of stock material,uninodal cuttings of about 3-4 mm in length were prepared from in vitro proliferated potato plants by excising leaves of 1-2 mm on each side of the node.Prepared uninodal cuttings were cultured on 1/2 strength MS medium for root primordia development.The selected uninodal cuttings with root primordia were encapsulated with sodium alginate solution(3.5%(w/v)),mixed with 1.25%charcoal and different concentration of fungicide(thiophanate methyl,sigma)to enhance the viability percentage of synthetic seed.Furthermore,these encapsulated uninodal cuttings were subjected to different storage intervals to check maximum storage.Results showed that optimum dose for fungicide is 150 mg/L as it resulted in good viability percentage,shoot number,shoot length,rooting percentage,root number,root length and ideal for bead formation with sodium alginate.Similarly,results revealed that encapsulated uninodal cuttings can be stored at a temperature of 4℃ up to 45 days with a survival rate of 63.33%.Encapsulated uninodal cutting stored for 60 days showed a poor viability percentage of about 43.03%.It can be concluded that optimum dose of 150 mg/L with storage time of 45 days should be used to get a better outcome for synthetic potato seed production.
基金Agricultural Science and Technology Development and Resource and Environmental Protection Management Fund of Guangdong Provincial Rural Revitalization Strategy Project(2022KJ153-06)Special Fund for China Agricultural Industry Research System(CARS-01-32,2022KJ105)+1 种基金"The 14 th Five-Year Plan"New Discipline Team Building Project of Guangdong Academy of Agricultural Sciences(202116TD)Science and Technology Plan Project of Shaoguan(210804164531395).
文摘[Objectives]The paper was to identify the characteristics and the potency of new fungicides to rice blast disease,and study their preventive and therapeutic effects on the disease.[Methods]Six new and conventional fungicides with different mechanisms of action were selected to compare their preventive and therapeutic effects on rice seedling blast in greenhouse.[Results]The agents which showed to be highly efficacious in blast prevention(greater than 90%)were 25%pyraclostrobin EC,20%fenoxanil SC,75%tricyclazole WP and 50%prochloraz-manganese WP sprayed at the dosages of 112.5-150,180-360,270-450 and 450-600 g/ha,respectively.The therapeutic effect of new fungicides 25%pyraclostrobin EC and 50%prochloraz-manganese WP on rice blast were above 90%when the dosages were 90-150 and 360-600 g/ha,respectively.The therapeutic effect of the conventional fungicide 40%isoprothiolane EC on rice blast was 69.04%when the dosage was 480 g/ha,while those of other fungicides were worse.[Conclusions]Both 25%pyraclostrobin EC and 50%prochloraz-manganese WP have good preventive and therapeutic effects on rice blast,which will provide a reference for the use of these fungicides in the field.
文摘Natural antiseptic formulas are increasingly favored by consumers. This article take preservatives compounded from cinnamon, sophora flavescens and other plant extracts as the main research object, evaluated its antibacterial efficacy and application in cosmetics, expect that it can be used in cosmetics to replace conventional chemical preservatives. Research on its antibacterial efficacy through inhibition zone and MIC experiment, and product application research used anti-corrosion challenge and antibacterial rate experiment. The results showed that the plant-derived antiseptic system had a broad antibacterial spectrum, inhibition of 10 different common pathogenic bacteria, and had a very significant inhibitory effect on Gram-positive bacteria and fungi;Among them, the diameter of the antibacterial circle for Bacillus subtilis and Aspergillus niger can reached 31.89 mm and 28.26 mm, while the MIC value was 0.4 mg/mL and 0.8 mg/mL. The spray product with 1.5% addition amount successfully passed the anti-corrosion challenge test and meets the anti-corrosion standard requirements;The 2% added amount of disposable gel product has an inhibitory rate of 51.05% and 70.74% against Escherichia coli and Staphylococcus aureus within 20 minutes of action. In summary, the plantderived compound preservative has ability to be used in cosmetic preservative systems.
基金sponsored by the National Natural Science Foundation of China (30971891)the Natural Science Foundation of Jiangsu Province, China(BK2008337)the Anhui Provincial Natural Sci-ence Foundation,China (10040606Q26)
文摘This report reviews the characteristics of JS399-19, a novel cyanoacrylate fungicide. JS399-19 strongly inhibits the mycelial growth of the fungal plant pathogens of the genus Fusarium and exhibits great potential in controlling Fusarium head blight (FHB) on wheat and other cereals. The mode of action of JS399-19 is evidently different from that of benzimidazole (for example, carbendazim) and other sort of fungicides, making it a possible replacement for carbendazim in China to manage carbendazim-resistant subpopulations of Fusarium graminearum and F. asiaticum. JS399-t9 has excellent protective and curative activity against these pathogens. Incorrect use of this fungicide, however, is likely to select for resistance. Among JS399-19-resistant mutants of F. asiaticum induced in the laboratory, the resistant level of mutants was high and the phenotype of resistance against JS399-19 was conferred by a major gene by genetic analysis. The fitness of laboratory-induced JS399-19-resistant mutants of F. asiaticum was nearly equal to that of their parents. JS399-19 lacks cross resistance with other sort fungicides. To control FHB with JS399-19 and to delay the development of the fungicide-resistance, farmers should use tank mixtures containing JS399-19 and carbendazim, metconazole, tebuconazole, or prothioconazole.
基金supported by the National Natural Science Foundation of China (No.30600082,20777089)the "Knowledge Innovation" Program of Chinese Academy of Sciences (No.kzcx1-yw-06-03)the Key Technologies R&D Program of China (No.2008BADA7B01)
文摘Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the γ-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.
基金supported by the National Natural Science Foundation of China (No. 81773911, 81690263 and 81573616)the Development Project of Shanghai Peak DisciplinesIntegrated Medicine (No. 20180101)。
文摘Nanotechnologies have been successfully applied to the treatment of various diseases.Plant-derived exosome-like nanoparticles (PENs) are expected to become effective therapeutic modalities for treating disease or in drug-delivery. PENs are minimally cytotoxic to healthy tissues, with which they show excellent biocompatibility, and are biased towards tumors by targeting specific tissues through special endocytosis mechanisms. Thus, the use of these PENs may expand the scope of drug therapies while reducing the off-target effects.In this review, we summarize the fundamental features and bioactivities of PENs extracted from the grape, grapefruit, ginger, lemon, and broccoli and discuss the applications of these particles as therapeutics and nanocarriers.
文摘The effects of biofungicide formula containing the biocontrol agent Trichoderma harzianum (Jn14) as wettable powder in combination with the fungicides pyrimethanil and a mixture of cyprodinil and flydioxonil on Botrytis cinerea of strawberry in vitro, in vivo and in greenhouse were studied. The pathogen B. cinerea was more affected in vitro by low concentrations of the fungicides tested above 0.4 μg·ml-1 than the bioagent T. harzianum (Jn14). The later was almost insensitive to pyrimethanil. In the same direction, gray mould disease severity on strawberry detached leaves and whole plants was reduced up to 89% by the tested fungicides, compared to the control, while the application of T. harzianum (Jn14) alone reduced disease severity up to 45% on strawberry detached leaves, compared to the control. In the integrated control approach, the combination of T. harzianum (Jn14) with higher concentrations of the tested fungicides (ED50) completely inhibited strawberry gray mould disease severity in pots and the greenhouse.
基金supported by Cooperation Project between China and Poland Government of Ministry of Science and Technology of China(AM30:001(30-20))the National Natural Science Foundation of China(30370911).
文摘Two seed lots of lettuce (Lactuca sativa L.) cv. Krlowa Majowych were primed in polyethylene glycol (PEG) 8000 at -1.25MPa for 7 days in dark at 20C. Two fungicide treatments combined with PEG were used to control fungi: 1) Funaben T(0.1%) and Apron 35 SD (0.02%) were added to -1.25 MPa PEG solution (PEG+F); 2) After seed priming and drying,Funaben T was mixed at 5 g kg-1 and Apron 35 SD at 1 g kg-1 of seeds (PEG then F dust). PEG, PEG+F and PEG then F dusttreatments reduced significantly thermodormancy and increased the seed germination at 35C in both lots. PEG then Fdust treatment had the best effect on reducing seed thermodormancy at 35C, and increased seed germination to 64.5% inlot 1 and 72.0% in lot 2 compared to 0 in untreated. PEG and PEG then F dust treatments have accelerated germinationspeed at 20 and 15C in both lots. There was a significant reduction in seed infestation in which the seeds were treatedwith PEG+F and PEG then F dust compared to untreated seeds and PEG primed seeds. PEG priming enhanced seedinfestation considerably by Alternaria alternata, Penicillium spp., Rhizopus spp. and Ulocladium spp. Mycologicalanalysis showed higher frequency of Alternaria alternata and Ulocladium spp. in untreated seeds at 20C. Priming incombination with fungicides significantly alleviated the infestation of fungi, especially Alternaria alternata infestation.
基金Supported by Key R&D Program of Shandong Province(2018GNC110013)the Innovative Project of Forestry Science and Technology of Shandong Provinc of China(LYCX04-2018-23)Agricultural Improved Seed Project of Shandong Province(2016LZG012)
文摘In this research,the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among the 16 tested fungicides,10% of Difenoconazole WG,33. 5% of Copper quinolate SC,25%of Bromothalonil EC,70% of Mancozeb WP,430 g/L of Tebuconazole SC,50% of Prochloraz-manganese chloride and 400 g/L of Flusilazole EC achieved the best inhibitory effect on mycelial growth of C. horri,with the inhibition rate of 100%; 70% of Polyram WG,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP,50% of Chlorobromoisocyanuric acid AF,50% of Triram WP and 400 g/L of Flusilazole achieved the best inhibitory effect on spore germination of C. horri,with the germination rate of 0. In conclusion,33. 5% of Copper quinolate SC,25% of Bromothalonil EC,70% of Mancozeb WP and 400 g/L of Flusilazole EC achieved the best inhibitory effect both in mycelial growth and spore germination,which could be used as the preference fungicides for the control of persimmon anthracnose,and 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect,which could be used as alternative fungicides. The results of this research could provide scientific evidence for the effective control of persimmon anthracnose,and more optional pesticides for utilization in the production practice of persimmon industry.
基金supported by the National Science Fund for Distinguished Young Scholars of China(30225030)the National Natural Science Foundation of China(30170663)the Natural Science Foundation of Beijing(6012005).
文摘The yeasts Cryptococcus laurentii, Trichosporon pullulans, Rhodotorula glutinis andTrichosporon sp.were used to investigate their sensitivity to four fungicides anddifferent concentrations of CO2, as well as their antagonistic ability to Penicilliumexpansumand Alternariaalternata in vitro when applied with fungicide. There were significantdifferences in sensitivity to the fungicides among the different yeasts(P=0.05). R.glutinis was more sensitive to Deccocil, Iprodione and Stroby as compared to otheryeasts. Combination antagonistic yeasts with fungicide could more significantly enhancebiocontrol ability of the yeasts against the pathogenic fungi in vitro(P = 0.05). C.laurentii was the most effective antagonist among the four yeasts and could completelycontrol spore germination of P.expansum and A.alternata when combined with Stroby at theconcentration of 100 L L-1. The yeasts, except R.glutinis, could grow well on nutrientyeast dextrose agar (NYDA) after 8 d incubation even at 20% CO2 concentration at 25℃.Particularly Trichosporon sp. showeda better adaptability to low temperature as comparedto other antagonists.
文摘Wheat blast, caused by a fungal pathogen, <i><span style="font-family:Verdana;">Magnaporthe oryzae Tritichum </span></i><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">MoT</span></i><span style="font-family:Verdana;">) pathotype (wheat isolates), was first reported in Bangladesh among Asian countries in 2016. It is a serious disease of wheat causing yield failures and significant economic losses during epidemic years. Extensive use of persistent synthetic pesticides to control notorious wheat blast imposes enormous threat to human health and environment. In addition, the increasing demand for organic food has stimulated people to look for alternative methods. Nowadays, the need for synthetic chemical-free agricultural practices is gaining importance due to effective in managing crop pests, inexpensive, biodegradable, easily available and have low toxicity to non-target organisms. In order to identify active plants, 12 kinds of methanol extracts obtained from 12 medicinal plants were conducted </span><i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> to test the effect against </span><i><span style="font-family:Verdana;">Magnaporthe oryzae Triticum </span></i><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">MoT</span></i><span style="font-family:Verdana;">) pathotype. The remarkable inhibitory activity {(29.6 ± 01.5) mm, (25.1 ± 01.0) mm and (20.0 ± 02.0) mm zone of inhibition)} exhibited by the extracts (5 mg/disk) obtained from </span><i><span style="font-family:Verdana;">Artemisia indica</span></i><span style="font-family:Verdana;"> (Nagdona), </span><i><span style="font-family:Verdana;">Persicaria orientalis</span></i><span style="font-family:Verdana;"> (Bishkatali) and </span><i><span style="font-family:Verdana;">Clerodendrum indicum</span></i><span style="font-family:Verdana;"> (Bamonhati), respectively. Other medicinal plant extracts did not show any significant or no activity at all. Therefore, the three plant extracts might be a promising source for developing natural fungicides against wheat blast.</span>
文摘Tolerance in isolations of Trichoderma was developed by exposing two strains of T. harzianum and three of T. asperelloides to increasing concentrations of chemical fungicides. These isolation of Trichoderma were exposed to three fungicides: Captan, Thiabendazol and the mixture Captan-Carboxin. Some selected lines of these strains reached tolerance to Captan and partial tolerance to the mixture Captan-Carboxin. The biological and genetic changes in these tolerant lines were monitored by determining the relative growth rate of the fungus, inhibition of Fusarium and by analyzing the genomic changes through UP-PCR. The results show that the tolerance to fungicides can be developed without affecting the parameters of biological activity in these lines of Trichoderma (growth and parasitism against Fusarium). Chemical tolerance to the fungicide was verified by means of changes at the DNA level (UP-PCR), mainly in the lines tolerant to Captan. This suggests that Trichoderma survives in environments with remnants of fungicide molecules.
基金Supported by College-Enterprise Cooperation Project of Yanbian University[(2015)6]
文摘There are few kinds of fungicides for the prevention and treatment of Rhizoctonia solani,and the excessive use of chemical fungicides can cause many hazards and toxic and side effects,not in line with the requirements of rice planting. The mixed use of wood vinegar and chemical fungicides can reduce the use of chemical fungicides,alleviate pollution and improve rice quality. In this experiment,the Horsfall method was used to study the synergistic inhibiting effect of mixture between wood vinegar and chemical fungicides on the growth of Rhizoctonia solani,as well as the optimal ratio. The results showed that when wood vinegar was mixed with Captan,the synergistic mixture ratio was 4∶6,3∶ 7 or 1∶ 9,and the toxicity ratio under mixture ratio of 4∶ 6 and 1∶ 9 was 1. 75 and 1. 99,respectively,with significant synergistic effect;when wood vinegar was mixed with Chlorothalonil,the toxicity ratio(1. 08) under mixture ratio of 8∶ 2 was greater than 1,showing additive effect.
文摘The morphophysiological and molecular-genetic parameters of T. caries isolates collected from various fields of Southern Urals agrocenoses have been analysed. Isolate 1 of wheat callus had a high growth rate in vitro even in the presence of 0.1 mg/l fungicide Baitan. Isolate 2 of wheat callus had a low growth rate whereas 0.1 mg/l Baitan significantly inhibited its growth. Comparison of nucleotide sequences of 18S RNA gene of the two isolates showed high level of homology between them, but a large number of nucleotide substitutions have been found. The most characteristic excision was five nucleotides at position 461 of the isolate 2, compared with the isolate 1. Our results allow to assume that the environmental stress including high pesticide concentration may cause the resistance of T. caries pathogen to fungicides.
文摘Tobacco black shank caused by Phytophthora parasitica var.nicotianae(Breda de Hean)is one of the most serious diseases in tobacco growing,and few effective fungicides are available currently.The purpose of this study was to assess the feasibility of using fluazinam to treat tobacco black shank disease.In vitro toxicities of fluazinam to 62 isolates of P.nicotianae were determined by mycelial growth rate method.The EC50 values ranged from 0.294 6 to 2.389 9 μg/mL with a mean of 1.084 0 μg/mL.The sensitivity distribution was unimodal,and there was no resistant isolate in P.nicotianae population.The carboxylic acid amide(CAA)fungicides were single-site in action and activity to oomycetes.The synergistic interactions were tested by Wadley method between fluazinam and dimethomorph,flumorph,mandipropamid,respectively.The mixture containing dimethomoph:Huazinam at 1:2 ratio showed additive actions,with the synergy ratio of 1.2.The mixture containing flumorph and fluazinam at 1:5 ratio had the highest synergy ratio(SR 2.07).Mandipropamid and fluazinam had an additive interaction and the proportion of 2:1 had the lowest EC50 value(0.020 7 μg/mL).This study demonstrated the sensitivity of P.nicotianae to fluazinam,and provided the experimental foundation to use fluazinam for tobacco black shank management.