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

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.

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Stimulatory Effects of Sublethal Doses of Dimethachlon on Sclerotinia sclerotiorum

Plant Disease ◽

10.1094/pdis-10-13-1059-re ◽

2014 ◽

Vol 98 (10) ◽

pp. 1364-1370 ◽

Cited By ~ 21

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.

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Hormetic Effects of Carbendazim on the Virulence of Botrytis cinerea

Plant Disease ◽

10.1094/pdis-10-17-1602-re ◽

2018 ◽

Vol 102 (5) ◽

pp. 886-891 ◽

Cited By ~ 6

Author(s):

Menglong Cong ◽

Shun He ◽

Hongju Ma ◽

Guoqing Li ◽

Fuxing Zhu

Keyword(s):

Hydrogen Peroxide ◽

Disease Management ◽

Botrytis Cinerea ◽

Time Course ◽

Plant Pathogens ◽

Pathogenic Fungus ◽

Physiological Mechanism ◽

Potato Dextrose Agar ◽

Direct Stimulation ◽

Sublethal Doses

The ascomycete plant-pathogenic fungus Botrytis cinerea infects more than 1,400 plant species worldwide. Stimulatory effects of sublethal doses of fungicides on plant pathogens are of close relevance to disease management. In the present study, stimulatory effects of carbendazim on the virulence of B. cinerea to cucumber plants were investigated. Spraying carbendazim on cucumber plants at 3 to 200 μg/ml had stimulatory effects on the virulence of carbendazim-resistant isolates of B. cinerea and the maximum percent stimulations were 16.7 and 13.5% for isolates HBtom451 and HBstr491, respectively. Preconditioned mycelia (i.e., mycelia grown on potato dextrose agar [PDA] amended with carbendazim at concentrations of 10, 50, or 200 μg/ml) also showed increased virulence, and the maximum percent stimulations for isolates HBtom451 and HBstr491 were 7.9 and 9.5%, respectively. Compared with mycelia grown on PDA without carbendazim, virulence stimulation magnitudes of spraying carbendazim on leaves increased moderately but the concentrations of carbendazim that elicited the maximum stimulation increased 20- and 8-fold for preconditioned isolates HBtom451 and HBstr491, respectively. The time course of infection indicated that virulence stimulation was mediated by a direct stimulation mechanism. Studies of the physiological mechanism for stimulation demonstrated that carbendazim had no significant effects on tolerance to hydrogen peroxide, or on oxalic acid production in B. cinerea. These studies will deepen our understanding of quantitative features of hormetic effects of sublethal doses of fungicides on plant pathogens.

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Hypovirulence and Double-Stranded RNA in Botrytis cinerea

Phytopathology ◽

10.1094/phyto-97-12-1590 ◽

2007 ◽

Vol 97 (12) ◽

pp. 1590-1599 ◽

Cited By ~ 76

Author(s):

M. D. Wu ◽

L. Zhang ◽

G. Q. Li ◽

D. H. Jiang ◽

M. S. Hou ◽

...

Keyword(s):

Botrytis Cinerea ◽

Mycelial Growth ◽

Horizontal Transmission ◽

Potato Dextrose Agar ◽

Dutch Elm Disease ◽

Transmission Experiment ◽

Dsrna Element ◽

Double Stranded Rna ◽

Virulent Isolate ◽

Virulent Strains

Twenty-one strains of Botrytis cinerea isolated from 13 species of plants grown in China were compared for pathogenicity on Brassica napus, mycelial growth on potato dextrose agar, and presence of double-stranded (ds)RNA. The results showed that the strain CanBc-1 was severely debilitated in pathogenicity and mycelial growth, compared with the 20 virulent strains. A dsRNA of approximately 3.0 kb in length was detected in CanBc-1 and 4 hypovirulent single-conidium (SC) isolates of CanBc-1, but was not detected in the 20 virulent strains of B. cinerea and 4 virulent SC isolates of CanBc-1. Results of the horizontal transmission experiment showed that the hypovirulent trait of CanBc-1 was transmissible and the 3.0-kb dsRNA was involved in the transmission of hypovirulence. Analysis of a 920-bp cDNA sequence generated from the 3.0-kb dsRNA of CanBc-1 indicated that the dsRNA element was a mycovirus, designated as B. cinerea debilitation-related virus (BcDRV). Further analyses showed that BcDRV is closely related to Ophiostoma mitovirus 3b infecting O. novo-ulmi, the causal agent of Dutch elm disease. Mitochondria and cytoplasm in hyphal cells of CanBc-1 became degenerated, compared with the virulent isolate CanBc-1c-66 of B cinerea. This is the first report on the occurrence of Mitovirus-associated hypovirulence in B. cinerea.

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Hormetic Effects of Mixtures of Carbendazim and Iprodione on the Virulence of Botrytis cinerea

Plant Disease ◽

10.1094/pdis-05-18-0754-re ◽

2019 ◽

Vol 103 (1) ◽

pp. 95-101 ◽

Cited By ~ 2

Author(s):

Menglong Cong ◽

Shun He ◽

Jun Zhang ◽

Chaoxi Luo ◽

Fuxing Zhu

Keyword(s):

Botrytis Cinerea ◽

Mycelial Growth ◽

Plant Pathogens ◽

Pathogenic Fungi ◽

Potato Dextrose Agar ◽

Inhibitory Effects ◽

Additive Interaction ◽

Physiological Mechanisms ◽

Fungicide Mixtures ◽

Stimulation Of

Hormetic effects of fungicides on mycelial growth and virulence of plant pathogenic fungi have been reported, but the effects of fungicide mixtures on virulence hormesis of plant pathogens remain to be investigated. In this study, hormetic effects of mixtures of carbendazim and iprodione on the virulence of two carbendazim-resistant isolates of Botrytis cinerea were determined. Spraying carbendazim alone at 3 to 800 μg/ml exhibited hormetic effects on virulence to cucumber leaves, and carbendazim at 10 μg/ml had the maximum stimulation of 16.7% for isolate HBtom451. Spraying iprodione alone at 0.0001 to 0.0625 μg/ml exhibited hormetic effects on virulence, and iprodione at 0.025 μg/ml had the maximum stimulation of 18.7% for isolate HBtom451. However, spraying simultaneously carbendazim at 800 μg/ml and iprodione at 0.0625 μg/ml showed inhibitory effects on virulence to cucumber leaves. The mixture of carbendazim at 3 μg/ml and iprodione at 0.0001 μg/ml had much higher virulence stimulations than either fungicide at the same concentration alone. The maximum stimulation for the mixtures occurred at 10 and 0.0005 μg/ml for carbendazim and iprodione, respectively, and these concentrations were much lower than the concentration of their respective fungicide alone eliciting the maximum stimulations. The maximum stimulation amplitude for the mixture was slightly higher than that of each fungicide alone. These results demonstrated that carbendazim and iprodione mainly had dose-additive rather than amplitude-additive interactions when sprayed simultaneously with regard to virulence stimulations. Studies on virulence stimulations for mycelia treated with fungicide in potato dextrose agar showed that the maximum stimulation for the mixtures occurred at concentrations much lower than the concentration of carbendazim alone, indicating a dose-additive interaction when compared with carbendazim hormesis. Studies on potential physiological mechanisms of hormesis showed that increased tolerance to H2O2 may be one of the mechanisms for virulence hormesis for the mixtures of iprodione and carbendazim. These studies will advance our understanding of hormesis of fungicide mixtures.

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

Plant Disease ◽

10.1094/pdis-07-19-1421-re ◽

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.

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

Phytopathology ◽

10.1094/phyto-08-20-0364-r ◽

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.

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An Attempt at Biological Control of Blossom Blight of Rose Caused by Botrytis cinerea Using some Local Trichoderma spp. Strains

Acta Phytopathologica et Entomologica Hungarica ◽

10.1556/038.55.2020.010 ◽

2020 ◽

Vol 55 (1) ◽

pp. 27-34

Author(s):

G. Zadehdabagh ◽

K. Karimi ◽

M. Rezabaigi ◽

F. Ajamgard

Keyword(s):

Botrytis Cinerea ◽

Mycelial Growth ◽

Limiting Factor ◽

Dual Culture ◽

Trichoderma Spp ◽

Khuzestan Province ◽

Inhibitory Potential ◽

Cut Rose

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.

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Combination of Suspension Array and Mycelial Growth Assay for Detecting Multiple-Fungicide Resistance in Botrytis cinerea in Hebei Province in China

Plant Disease ◽

10.1094/pdis-07-18-1269-re ◽

2019 ◽

Vol 103 (6) ◽

pp. 1213-1219

Author(s):

Zehua Su ◽

Xin Zhang ◽

Jianjiang Zhao ◽

Wenqiao Wang ◽

Lei Shang ◽

...

Keyword(s):

Botrytis Cinerea ◽

High Throughput ◽

Fungicide Resistance ◽

Mycelial Growth ◽

Accurate Method ◽

Hebei Province ◽

Combination Method ◽

Major Type ◽

Suspension Array ◽

Growth Assay

To provide a high-throughput, efficient, and accurate method to monitor multiple-fungicide resistance of Botrytis cinerea in the field, we used the suspension array, sequencing, and mycelial growth assay in our research. Discriminating-dose bioassays for detecting carbendazim, diethofencarb, boscalid, and iprodione resistance (CarR, DieR, BosR, and IprR, respectively) were used to analyze 257 isolates collected from Hebei Province in China during 2016 and 2017. High resistance frequencies to carbendazim (100%), diethofencarb (92.08%), and iprodione (86.59%) were detected. BosR isolates accounted for 11.67% of the total. In addition, 103 isolates were randomly selected for phenotype and genotype detection. The high-throughput suspension array was utilized to detect eight genotypes simultaneously, including BenA-E198, BenA-198A, SdhB-H272, SdhB-272Y, BcOS1-I365, BcOS1-365S, erg27-F412, and erg27-412S, which were associated with resistance toward carbendazim or diethofencarb, boscalid, iprodione, and fenhexamid (FenR), respectively. Most of the benzimidazole-resistant isolates (81.55%) possessed the E198V mutation in the BenA gene. Ninety-three isolates with dual resistance to carbendazim and diethofencarb showed the E198V/K mutation. All BosR isolates carried the H272R mutation in the SdhB gene. The I365S and Q369P+N373S (66.99%) mutations in the BcOS1 gene were more frequently observed. No mutation was detected in the erg27 gene in Hebei isolates. There were 13 resistance profile phenotypes. Phenotypes with triple resistance were the most common (83.50%), and CarRDieRBosSIprRFenS was the major type. CarR isolates that carried E198V/K/A were all highly resistant (HR) and only one F200Y mutant was moderately resistant (MR) to carbendazim. Isolates that possessed E198V/K were MR or HR to diethofencarb. BosR isolates that possessed H272R mutation were lowly resistant (LR). IprR isolates were all LR or MR. The distribution of half maximal effective concentrations of CarR isolates with E198V/K mutations and IprR isolates with Q369P+N373S mutations significantly increased from 2016 to 2017. Combined with our observations, a combination method of the high-throughput suspension array and the mycelial growth assay was suggested to accurately monitor multiple resistance of B. cinerea in the field.

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Effects of Long-Wave UV Light on Monilinia Growth and Identification of Species

Plant Disease ◽

10.1094/pdis.1999.83.1.62 ◽

1999 ◽

Vol 83 (1) ◽

pp. 62-65 ◽

Cited By ~ 48

Author(s):

A. De Cal ◽

P. Melgarejo

Keyword(s):

Short Distance ◽

Mycelial Growth ◽

Uv Light ◽

Dark Period ◽

Morphological Characteristics ◽

Potato Dextrose Agar ◽

Long Wave ◽

The World ◽

Identification Of Species ◽

Respective Species

The effect of long-wave UV/dark period on mycelial growth of 46 isolates of Monilinia sp. collected in Spain and 16 isolates collected from other parts of the world was investigated. Typical isolates of M. laxa, M. fructigena, and M. fructicola were grown in the dark and identified by morphological characteristics. Long-wave UV/dark conditions reduced the growth rates of M. laxa, M. fructigena, and M. fructicola on potato dextrose agar. All isolates of M. fructigena grew more slowly than those of M. fructicola. Typical and atypical isolates of M. fructigena and M. fructicola were placed in their respective species based on long-wave UV/dark growth rate data. M. laxa isolates were readily distinguished by the short distance from their conidium to the first germ tube branch. The involvement of different photoreceptors in photoresponses by M. fructicola and M. fructigena is discussed. Differences in mycelial growth under long-wave UV may be a useful tool to identify Monilinia spp.

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Combination of Exercise Training and SOD Mimetic Tempol Enhances Upregulation of Nitric Oxide Synthase in the Kidney of Spontaneously Hypertensive Rats

International Journal of Hypertension ◽

10.1155/2020/2142740 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Pengyu Cao ◽

Osamu Ito ◽

Daisuke Ito ◽

Rong Rong ◽

Yang Zheng ◽

...

Keyword(s):

Nitric Oxide ◽

Exercise Training ◽

Nadph Oxidase ◽

Oxidase Activity ◽

Spontaneously Hypertensive Rats ◽

Hypertensive Rats ◽

Sod Activity ◽

Spontaneously Hypertensive ◽

Nadph Oxidase Activity ◽

Expression Levels

Both exercise training (Ex) and superoxide dismutase (SOD) mimetic tempol have antihypertensive and renal protective effects in rodent models of several hypertensions. We recently reported that Ex increases nitric oxide (NO) production and the expression levels of endothelial and neuronal NO synthase (eNOS and nNOS) in the kidney and aorta of the spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY). We also found that endogenous hydrogen peroxide (H2O2) upregulates the expression levels of eNOS and nNOS in SHR. To elucidate the mechanism of the Ex-upregulated NO system in the kidney, we examined the additive effect of Ex and tempol on the renal NO system in SHR and WKY. Our data showed that, in SHR, both Ex and tempol increase the levels of H2O2 and nitrate/nitrite (NOx) in plasma and urine. We also observed an increased renal NOS activity and upregulated expression levels of eNOS and nNOS with decreased NADPH oxidase activity. The effects of the combination of Ex and tempol on these variables were cumulate in SHR. On the other hand, we found that Ex increases these variables with increased renal NADPH oxidase activity, but tempol did not change these variables or affect the Ex-induced upregulation in the activity and expression of NOS in WKY. The SOD activity in the kidney and aorta was activated by tempol only in SHR, but not in WKY; whereas Ex increased SOD activity only in the aorta in both SHR and WKY. These results indicate that Ex-induced endogenous H2O2 produced in the blood vessel and other organs outside of the kidney may be carried to the kidney by blood flow and stimulates the NO system in the kidney.

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