Hormetic Effects of Dimethachlone on Mycelial Growth and Virulence of Sclerotinia sclerotiorum

2020 ◽  
Author(s):  
Simin Hu ◽  
li jin li ◽  
Pengju Wang ◽  
Fuxing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Plant Pathogen ◽  
Mycelial Growth ◽  
Control Plant ◽  
Potato Dextrose Agar ◽  
Plant Diseases ◽  
Sublethal Doses ◽  
Encoding Gene ◽  
Polygalacturonase Gene ◽  
Stimulation Amplitude

Fungicide hormesis has implications for the application of fungicides to control plant diseases. We investigated the hormetic effects of the dicarboximide fungicide dimethachlone on mycelial growth and virulence of the necrotrophic plant pathogen Sclerotinia sclerotiorum. Dimethachlone at sublethal doses in potato dextrose agar (PDA) increased the mycelial growth of S. sclerotiorum. After the growth-stimulated mycelia were sub-cultured on fresh PDA and inoculated on rapeseed leaves, increased mycelial growth and virulence were observed, indicating that hormetic traits were passed down to the next generation. Dimethachlone applied to leaves at 0.002 to 500 μg/mL stimulated virulence, with a maximum stimulation amplitude (MSA) of 31.4% for the isolate HLJ4, which occurred at 2 μg/mL. Dimethachlone resistant isolates and transformants had a mean virulence MSA of 30.4%, which was significantly higher (P = 0.008) than the MSA for sensitive isolates (16.2%). Negative correlations were detected between MSA and virulence in the absence of any fungicide (r = -0.872, P < 0.001) and between MSA and mycelial growth on PDA (r = -0.794, P = 0.002). Studies on hormetic mechanisms indicated that dimethachlone had no significant effects on expression levels of three virulence-associated genes, i.e., a cutinase encoding gene SsCut, a polygalacturonase gene SsPG1, or an oxaloacetate acetylhydrolase gene SsOah1. The results will contribute to understanding hormesis and have implications for the judicious application of fungicides to control plant diseases.

scholarly journals Stimulatory Effects of Sublethal Doses of Dimethachlon on Sclerotinia sclerotiorum

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Feng Zhou ◽  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Oilseed Rape ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Plant Disease ◽  
Pathogenic Fungi ◽  
Potato Dextrose Agar ◽  
Detached Leaves ◽  
Sublethal Doses ◽  
Fungal Phytopathogens ◽  
Plant Disease Management

Growth and virulence stimulations of sublethal doses of fungicides on plant-pathogenic fungi and oomycetes have been reported and the stimulatory effects are potentially relevant to plant disease management. Sclerotinia sclerotiorum is one of the most devastating and economically important necrotrophic fungal phytopathogens, capable of infecting more than 400 species of plants worldwide. In order to study stimulatory effects of sublethal doses of fungicides on S. sclerotiorum, 55 dimethachlon-sensitive isolates and 3 dimethachlon-resistant isolates of S. sclerotiorum were assayed to determine effects of sublethal doses of dimethachlon on mycelial growth rate on potato dextrose agar (PDA) media and virulence on oilseed rape plants. Results showed that all 3 dimethachlon-resistant isolates and 13 of the 55 sensitive isolates exhibited stimulatory responses to sublethal doses of dimethachlon. Dimethachlon-resistant isolates grew significantly (P < 0.05) faster on PDA media amended with dimethachlon at 0.5 to 4 μg/ml than on fungicide-free PDA media. As for virulence on detached leaves of oilseed rape plants, lesion diameters of dimethachlon-resistant isolates after growth on PDA media amended with dimethachlon at 0.5 to 2 μg/ml were significantly larger (P < 0.05) than the control. The maximum stimulatory effects were 42.40 to 59.80%. In pot experiments, for both dimethachlon-sensitive and -resistant isolates, significant (P < 0.05) virulence stimulations were observed after spraying with dimethachlon at a concentration of 2 μg/ml. After growing on dimethachlon-amended PDA media, H2O2 sensitivity of S. sclerotiorum decreased significantly (P < 0.05) compared with the nonamended PDA control.

scholarly journals Stimulatory Effects of Boscalid on Virulence of Sclerotinia sclerotiorum Indicate Hormesis May Be Masked by Inhibitions

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 833-840
Author(s):  
Simin Hu ◽  
Qianru Xu ◽  
Yuchao Zhang ◽  
Fuxing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Negative Correlation ◽  
Plant Pathogen ◽  
Mycelial Growth ◽  
Molecular Mechanisms ◽  
Potato Dextrose Agar ◽  
Dosage Range ◽  
Expression Levels ◽  
The Future ◽  
Different Levels

Hormetic effects of fungicides on phytopathogens are of great importance for proper application of fungicides. The aim of the present study was to investigate the stimulatory effects of the fungicide boscalid on mycelial growth and virulence of the devastating plant pathogen Sclerotinia sclerotiorum. Boscalid in potato dextrose agar (PDA) at a dosage range from 0.0005 to 0.002 μg/ml exerted statistically significant (P ≤ 0.015) stimulations on mycelial growth of S. sclerotiorum, and the maximum stimulation magnitudes were 5.55 ± 0.73% (mean ± SD) for the four isolates tested. Boscalid in PDA at 0.02 μg/ml inhibited mycelial growth of isolates HLJ3H and HLJ4H by 15.0 and 8.9%, respectively. However, after the growth-inhibited mycelia were inoculated on rapeseed leaves, isolates HLJ3H and HLJ4H exhibited virulence stimulations of 8.7 and 17.8%, respectively, indicating that hormesis may be masked by inhibitions. Boscalid sprayed at 0.0001 to 0.1 μg/ml on detached rapeseed leaves had significant (P ≤ 0.041) stimulations on virulence of S. sclerotiorum, and the maximum stimulation magnitudes were 17.90 ± 5.94% (mean ± SD) for the four isolates tested. Experiments on 12 isolates with different levels of virulence showed there was a negative correlation (R = –0.663, P = 0.019) between the maximum virulence stimulation magnitude and virulence of S. sclerotiorum in the absence of fungicide. Boscalid at stimulatory concentrations had no significant effect on the expression levels of three virulence-associated genes that encode cutinase (SsCut), polygalacturonase (SsPG1), and oxaloacetate acetylhydrolase (SsOah1). The molecular mechanisms for hormetic effects of boscalid on S. sclerotiorum remain to be studied in the future.

scholarly journals Effect of Osmotic and Matric Potentials on Sclerotinia minor and Sclerotinia sclerotiorum Virulence on Peanut

2016 ◽  
Vol 4 (3) ◽  
pp. 147-158 ◽  
Author(s):  
Ahmed Abd-Elmagid ◽  
Robert Hunger ◽  
Carla Garzón ◽  
Mark Payton ◽  
Ho-Jong Ju ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Vegetative Growth ◽  
Mycelial Growth ◽  
Potato Dextrose Agar ◽  
Matric Potential ◽  
Progress Curve ◽  
High Concentrations ◽  
Matric Stress ◽  
Osmotic Potentials ◽  
Sclerotial Germination

The effect of osmotic and matric potentials on mycelial growth, sclerotia production, germination, and virulence of two isolates of Sclerotinia sclerotiorum, and one isolate of S. minor were studied on potato dextrose agar (PDA) media adjusted with KCl, glycerol, or agar. Osmotic potentials created by KCl and glycerol significantly reduced vegetative growth of the three isolates. On matrically adjusted PDA, vegetative growth of the three isolates was not negatively affected by matric stress up to -3.5 MPa. When KCl was the osmoticum, sclerotia number did not follow a consistent pattern. However, sclerotia number decreased when osmotic stress created by glycerol was increased. Matric stress was not a consistent factor affecting sclerotia production by both species.  However, the highest levels of matric stress -3.0 and -3.5 MPa significantly reduced sclerotia production by both species. In general, there was a trend toward lower sclerotial germination with increasing osmotic and matric stress. Pathogenicity of S. minor and S. sclerotiorum on the peanut cultivar (Okrun) was reduced by high concentrations of KCl. Mycelia of both species produced at high matric potential -3.5 MPa did not differ in pathogenicity on Okrun compared with mycelia grown on non-amended PDA. In water-stressed-Okrun, induced by polyethylene glycol 8000, the Area under Disease Progress Curve (AUDPC) was significantly decreased. The relevance of these results to the behavior of S. minor and S. sclerotiorum, and their pathogenicity on peanut is discussed.

scholarly journals Stimulatory Effects of Sublethal Doses of Carbendazim on the Virulence and Sclerotial Production of Botrytis cinerea

Plant Disease ◽  
2019 ◽  
Vol 103 (9) ◽  
pp. 2385-2391 ◽  
Author(s):  
Menglong Cong ◽  
Bao Zhang ◽  
Kunyu Zhang ◽  
Guoqing Li ◽  
Fuxing Zhu
Keyword(s):  
Nadph Oxidase ◽  
Botrytis Cinerea ◽  
Mycelial Growth ◽  
Pectin Methylesterase ◽  
Potato Dextrose Agar ◽  
Low Doses ◽  
Xylanase Gene ◽  
Oxidase Gene ◽  
Expression Levels ◽  
Sublethal Doses

Stimulatory effects of low doses of fungicides on the virulence of phytopathogens have profound implications for applications of fungicides. The present study demonstrated that carbendazim sprayed at 0.001 to 0.03 μg/ml had stimulatory effects on the virulence of mycelia of Botrytis cinerea, and the maximum percent stimulations were 15.5 and 21.4% for isolates HB459 and HB536, respectively. Potato dextrose agar (PDA) amended with carbendazim at 0.01, 0.02, and 0.05 μg/ml inhibited mycelial growth of isolate HB536 by 0.8, 10.0, and 30.6%, respectively. However, after the inhibited mycelia were inoculated on cucumber leaves, virulence increased by 10.1, 12.9, and 10.8%, respectively. With respect to sclerotial production, carbendazim at 0.005 and 0.02 μg/ml in PDA significantly (P < 0.05) increased, while at 0.1 μg/ml significantly (P < 0.05) reduced the sclerotial number and weight of both isolates compared with nontreated controls. Conidia germination percentages slightly yet statistically significantly (P < 0.05) increased after being inoculated on PDA amended with carbendazim at 0.001 and 0.005 μg/ml. Carbendazim at 0.001∼0.02 μg/ml, either sprayed on cucumber leaves or cosuspended with conidia, exerted significantly (P < 0.05) stimulatory effects on the virulence of B. cinerea conidia. Mechanism studies showed that sublethal doses of carbendazim did not increase the expression levels of pathogenicity-related pectin methylesterase gene Bcpme1, endopolygalacturonase gene Bcpg2, cutinase gene CutA, xylanase gene Xyn11A, or NADPH oxidase gene BcnoxA.

scholarly journals Forest Tree Associated Bacterial Diffusible and Volatile Organic Compounds against Various Phytopathogenic Fungi

2020 ◽  
Vol 8 (4) ◽  
pp. 590 ◽  
Author(s):  
Wei-Liang Kong ◽  
Pu-Sheng Li ◽  
Xiao-Qin Wu ◽  
Tian-Yu Wu ◽  
Xiao-Rui Sun
Keyword(s):  
Control Plant ◽  
Pathogenic Fungi ◽  
Plant Growth Promoting Rhizobacteria ◽  
Forest Tree ◽  
Phytopathogenic Fungi ◽  
Plant Diseases ◽  
Pseudomonas Sp ◽  
Headspace Collection ◽  
Plant Growth Promoting ◽  
Encoding Gene

Plant growth-promoting rhizobacteria (PGPR) can potentially be used as an alternative strategy to control plant diseases. In this study, strain ST–TJ4 isolated from the rhizosphere soil of a healthy poplar was found to have a strong antifungal activity against 11 phytopathogenic fungi in agriculture and forestry. Strain ST–TJ4 was identified as Pseudomonas sp. based on 16S rRNA-encoding gene sequences. The bacterium can produce siderophores, cellulase, and protease, and has genes involved in the synthesis of phenazine, 1–phenazinecarboxylic acid, pyrrolnitrin, and hydrogen cyanide. Additionally, the volatile compounds released by strain ST–TJ4 can inhibit the mycelial growth of plant pathogenic fungi more than diffusible substances can. Based on volatile compound profiles of strain ST–TJ4 obtained from headspace collection and GC–MS/MS analysis, 1-undecene was identified. In summary, the results suggested that Pseudomonas sp. ST–TJ4 can be used as a biocontrol agent for various plant diseases caused by phytopathogenic fungi.

scholarly journals Development of Sclerotia and Apothecia of Sclerotinia sclerotiorum from Infected Soybean Seed and Its Control by Fungicide Seed Treatment

Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1113-1115 ◽  
Author(s):  
D. S. Mueller ◽  
G. L. Hartman ◽  
W. L. Pedersen
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Radial Growth ◽  
Mycelial Growth ◽  
Seed Treatment ◽  
Soybean Seed ◽  
Potato Dextrose Agar ◽  
Field Soil ◽  
Laboratory Studies ◽  
Infected Seed ◽  
Seed Coats

Field and laboratory studies were done to evaluate the development of sclerotia and apothecia of Sclerotinia sclerotiorum from soybeans and its control with fungicide seed treatment. Soybean seed infected with S. sclerotiorum produced mycelia on both seed coats and cotyledons after 48 h on potato dextrose agar (PDA). Obviously infected soybean seed also were placed in aluminum pans containing field soil and placed in soybean fields near Urbana, Illinois and Clinton, Wisconsin. In 1997, a total of 553 sclerotia, 20 stipes, and 10 apothecia were produced from 500 infected seeds. In 1998, 201 sclerotia and 22 stipes were produced, but no apothecia were observed from the 500 infected seeds. Fludioxonil was the most effective fungicide for reducing radial growth of S. sclerotiorum on PDA plates and suppressed 99% of the radial growth at 0.1 μg a.i./ml. S. sclerotiorum was recovered from 2% of soybean seed lots containing infected seed. When this seed lot was treated with several fungicides, captan + pentachloronitrobenzene + thiabendazole and fludioxonil completely inhibited mycelial growth from infected seed; thiram and thiabendazole each reduced recovery of S. sclerotiorum by 90%. In the field, 754 sclerotia and 10 apothecia were produced from 1,000 infected seeds over a two-year period. When evaluating fungicide control in the field, thiram, fludioxonil, and captan + pentachloronitrobenzene + thiabendazole reduced sclerotia formation from infected seed by more than 98%.

scholarly journals Assess the severity of Sclerotinia sclerotiorum isolate on peas Pisum sativum. L

2019 ◽  
pp. 316-326
Author(s):  
Zanib Al-Sadiq Al-bozidy ◽  
Najat Khalifa El-Gariani ◽  
Mohammed Alsaghir
Keyword(s):  
Seed Germination ◽  
Pisum Sativum ◽  
Sclerotinia Sclerotiorum ◽  
Agricultural Production ◽  
Potato Dextrose Agar ◽  
Plant Diseases ◽  
Local Variety ◽  
Field Crops ◽  
Pisum Sativum L ◽  
Fungal Suspension

Pisum sativum. L is one of the most important legumes and vegetables. It is an essential source of energy and highly rich in protein. Peas are affected by many plant diseases, Sclerotinia sclerotiorum, which affects many vegetable and field crops plants causing significant losses in agricultural production. S. sclerotiorum was isolated from infected pea pods on Potato Dextrose Agar (PDA) media. the percentage of seed germination was investigated for both local and Italian varities, also the effect of fungus on seeds and bodes was evaluated. Results of this study showed that the percentage of seed germination in the local varity was 98%, while in the Italian varity 90%. The ability of pathogenicity was high on seeds and bods of the local variety. and also the effect of S. sclerotiorum suspension when using perlite showed that the fungus hed a high effecte on the plant growth and seed germination comparied with sclerotia treatment on local variety only, while the effect of fungal suspension decreased seed and plant germination on petmous comparied with sclerotia treatment.

scholarly journals Hormetic Effects of Mixtures of Dimethachlone and Prochloraz on Sclerotinia sclerotiorum

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 546-554 ◽  
Author(s):  
Ran Zhang ◽  
Yuchao Zhang ◽  
Qianru Xu ◽  
Jianhong Li ◽  
Fuxing Zhu
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Cell Membrane Permeability ◽  
Phytopathogenic Fungus ◽  
Inhibitory Effects ◽  
Fungicide Mixtures ◽  
Sublethal Doses ◽  
Additive Interactions

Previous studies showed that dimethachlone has significant hormetic effects on phytopathogenic fungus Sclerotinia sclerotiorum. The present study investigated hormetic effects of mixtures of dimethachlone and prochloraz on mycelial growth and virulence of two dimethachlone-resistant isolates of S. sclerotiorum. The stimulatory dimethachlone dosage range was around 1 to 100 μg/ml in potato dextrose agar (PDA) medium for mycelial growth of the two isolates, and dimethachlone at 10 and 50 μg/ml had the maximum percent stimulations of 80.6 and 19.3% for isolates JMS14 and HLJ4, respectively. Prochloraz at 0.0003 and 0.002 μg/ml had the maximum percent stimulations of 9.3 and 11.1% for isolates JMS14 and HLJ4, respectively. However, dimethachlone and prochloraz mixed at their respective stimulatory concentrations had the maximum percent stimulations of 48.1 and 9.3% for isolates JMS14 and HLJ4, respectively. After the mycelia with increased and inhibited growth on fungicide-amended PDA were subcultured on PDA without fungicide, mycelial growth for the second generation increased compared with the nontreated control. After the mycelia grown on fungicide-amended PDA were inoculated on rapeseed leaves, the amplitude of virulence stimulation was much greater than that of mycelial growth on PDA amended with fungicide, and the inhibited mycelia also showed substantially increased virulence on leaves. The mixture of dimethachlone at 100 μg/ml and prochloraz at 0.03 μg/ml in PDA inhibited mycelial growth of isolate JMS14 by 59.4%; however, after the inhibited mycelia were inoculated on rapeseed leaves, virulence was stimulated by 69.0%. Spraying sublethal doses of dimethachlone and prochloraz on rapeseed leaves also exhibited significant stimulatory effects on virulence. For isolate JMS14, the stimulatory concentration ranges for dimethachlone and prochloraz were around 1 to 600 μg/ml and 0.0003 to 0.18 μg/ml, respectively. The fitted curve of virulence stimulation for the mixture of dimethachlone and prochloraz shifted to the left on the x axis, denoting dose-additive interactions between the two fungicides with regard to virulence stimulation. Spraying dimethachlone alone at 10 to 50 μg/ml had significant stimulations on virulence, whereas prochloraz alone at 10 to 50 μg/ml had significant inhibitory effects on virulence, and the mixture of dimethachlone and prochloraz at the concentration ratio of 1:1 had greater inhibitory effects than prochloraz alone, indicating dose-additive interactions for the inhibitory effects. Dimethachlone and prochloraz and their mixtures increased tolerance of mycelia to hydrogen peroxide. Dimethachlone significantly increased, whereas prochloraz reduced mycelial cell membrane permeability, and the mixture of the two fungicides had effect-additive interactions with respect to effects on cell membrane permeability. These studies will advance our understanding of hormesis of fungicide mixtures.

scholarly journals ε-poly-L-lysine Affects the Vegetative Growth, Pathogenicity and Expression Regulation of Necrotrophic Pathogen Sclerotinia sclerotiorum and Botrytis cinerea

2021 ◽  
Vol 7 (10) ◽  
pp. 821
Author(s):  
Tao Zhou ◽  
He Liu ◽  
Yuanmin Huang ◽  
Zehao Wang ◽  
Yuhang Shan ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Sclerotinia Sclerotiorum ◽  
Stress Responses ◽  
Control Plant ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Plant Diseases ◽  
Necrotrophic Pathogen ◽  
Differential Expressed Genes ◽  
Toxic Food

Microbial secondary metabolites produced by Streptomyces are applied to control plant diseases. The metabolite, ε-poly-L-lysine (ε-PL), is a non-toxic food preservative, but the potential application of this compound as a microbial fungicide in agriculture is rarely reported. In this study, the effect and mode of action of ε-PL on two necrotrophic pathogenic fungi, Sclerotinia sclerotiorum and Botrytis cinerea, were investigated. The results showed that ε-PL effectively inhibited the mycelial growth of S. sclerotiorum and B. cinerea with EC50 values of 283 μg/mL and 281 μg/mL, respectively. In addition, ε-PL at the dose of 150 and 300 μg/mL reduced S. sclerotiorum sclerotia formation. The results of the RNA-seq and RT-qPCR validation indicated that ε-PL significantly regulated the gene expression of critical differential expressed genes (DEGs) involved in fungal growth, metabolism, pathogenicity, and induced an increase in the expression of the fungal stress responses and the detoxification genes. These results provided new insights for understanding the modes of action of ε-PL on S. sclerotiorum and B. cinerea and improved the sustainable management of these plant diseases.

Nanotechnology as a Smart Way to Promote the Growth of Plants and Control Plant Diseases

2021 ◽  
pp. 1-16
Author(s):  
Heba Mahmoud Mohammad Abdel‐Aziz ◽  
Mohammed Nagib Abdel‐ghany Hasaneen
Keyword(s):  
Control Plant ◽  
Plant Diseases ◽  
And Control
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