scholarly journals Triazole Sensitivity in a Contemporary Population of Fusarium graminearum from New York Wheat and Competitiveness of a Tebuconazole-Resistant Isolate

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 607-613 ◽  
Author(s):  
Pierri Spolti ◽  
Emerson M. Del Ponte ◽  
Yanhong Dong ◽  
Jaime A. Cummings ◽  
Gary C. Bergstrom
Keyword(s):  
New York ◽  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Field Isolate ◽  
Effective Concentration ◽  
Resistant Isolate ◽  
Head Blight ◽  
Future Studies ◽  
Sensitive Isolate ◽  
Mean Sensitivity

A sample of 50 isolates, including 25 each of the 3-acetyldeoxynivalenol and the 15-acetyldeoxynivalenol trichothecene genotype, from a contemporary collection of Fusarium graminearum associated with Fusarium head blight (FHB) of wheat in New York varied in sensitivity to tebuconazole (effective concentration leading to a 50% reduction of mycelial growth [EC50] of 0.28 to 8.09 mg/liter; μ = 1.12 mg/liter) and metconazole (0.05 to 0.86 mg/liter; μ = 0.33). Mean sensitivity did not differ between the trichothecene genotype groups. Isolate Gz448NY11 from Steuben County is the first tebuconazole-resistant field isolate of F. graminearum reported in the Americas and has the lowest sensitivity to tebuconazole (EC50 = 8.09 mg/liter) documented for this species. Suppression of FHB and deoxynivalenol (DON) following application of a commercial rate of tebuconazole was significantly diminished in plants inoculated with the tebuconazole-resistant isolate compared with those inoculated with a tebuconazole-sensitive isolate well documented for its aggressiveness and toxigenicity on wheat. There was no diminution of FHB and DON suppression with either isolate following application of metconazole. Significantly more individuals of the tebuconazole-resistant isolate were recovered from spikes inoculated with an equal mixture of the two isolates and sprayed with tebuconazole. Future studies are needed on the epidemiology and monitoring of triazole-resistant isolates to understand the risk that fungicide resistance poses to disease management and food security.

scholarly journals Activity of Demethylation Inhibitor Fungicide Metconazole on Chinese Fusarium graminearum Species Complex and Its Application in Carbendazim-Resistance Management of Fusarium Head Blight in Wheat

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 929-937 ◽  
Author(s):  
Yabing Duan ◽  
Xian Tao ◽  
Huahua Zhao ◽  
Xuemei Xiao ◽  
Meixia Li ◽  
...  
Keyword(s):  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Species Complex ◽  
Resistance Management ◽  
Head Blight ◽  
Grain Yields ◽  
Significant Difference ◽  
Fusarium Graminearum Species Complex ◽  
Demethylation Inhibitor

Fusarium graminearum species complex (FGSC), causing Fusarium head blight (FHB) of wheat, has species-specific geographical distributions in wheat-growing regions. In recent years, benzimidazole resistance of FHB pathogens has been largely widespread in China. Although the demethylation inhibitor fungicide metconazole has been used for FHB control in some countries, no information about metconazole sensitivity of Chinese FHB pathogen populations and efficacy of metconazole in FHB control in China is available. In this study, the sensitivity of FGSC to metconazole was measured with 32 carbendazim-sensitive strains and 35 carbendazim-resistant strains based on mycelial growth. The 50% effective concentration values of 67 strains were normally distributed and ranged from 0.0209 to 0.0838 μg ml−1, with a mean of 0.0481 ± 0.0134 μg ml−1. No significant difference in metconazole sensitivity was observed between carbendazim-sensitive and -resistant populations. An interactive effect of metconazole and phenamacril, a novel cyanoacrilate fungicide approved in China against Fusarium spp., in inhibiting mycelial growth showed an additive interaction at different ratios. Furthermore, field trials to evaluate the effect of metconazole and metconazole + phenamacril treatments in FHB control, deoxynivalenol (DON) production, and grain yields were performed. Compared with the fungicides carbendazim and phenamacril currently used in China, metconazole exhibits a better efficacy for FHB control, DON production, and grain yields, and dramatically reduces use dosages of chemical compounds in the field. The mixture of metconazole and phenamacril at ratios of 2:3 and 1:2 showed the greatest efficacy for FHB control, DON production, and grain yields among all the fungicide treatments but its use dosages were higher in comparison with metconazole alone. In addition, FHB control, grain yields, and DON levels were significantly correlated with each other, showing that visual disease indices can be used as an indicator of grain yields and DON contamination. Meanwhile, the frequency of carbendazim-resistant alleles in F. graminearum populations was dramatically reduced after metconazole and phenamacril alone and the mixture of metconazole and phenamacril applications, indicating that metconazole and a mixture of metconazole and phenamacril can be used for carbendazim resistance management of FHB in wheat. Overall, the findings of this study provide important data for resistance management of FHB and reducing DON contamination in wheat grains.

scholarly journals Fusarium graminearum ATP-Binding Cassette Transporter Gene FgABCC9 Is Required for Its Transportation of Salicylic Acid, Fungicide Resistance, Mycelial Growth and Pathogenicity towards Wheat

2018 ◽  
Vol 19 (8) ◽  
pp. 2351 ◽  
Author(s):  
Peng-Fei Qi ◽  
Ya-Zhou Zhang ◽  
Cai-Hong Liu ◽  
Jing Zhu ◽  
Qing Chen ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Tertiary Structure ◽  
Severe Disease ◽  
Atp Binding ◽  
Head Blight ◽  
Transporter Family ◽  
Wide Range ◽  
Atp Binding Cassette

ATP-binding cassette (ABC) transporters hydrolyze ATP to transport a wide range of substrates. Fusarium graminearum is a major causal agent of Fusarium head blight, which is a severe disease in wheat worldwide. FgABCC9 (FG05_07325) encodes an ABC-C (ABC transporter family C) transporter in F. graminearum, which was highly expressed during the infection in wheat and was up-regulated by the plant defense hormone salicylic acid (SA) and the fungicide tebuconazole. The predicted tertiary structure of the FgABCC9 protein was consistent with the schematic of the ABC exporter. Deletion of FgABCC9 resulted in decreased mycelial growth, increased sensitivity to SA and tebuconazole, reduced accumulation of deoxynivalenol (DON), and less pathogenicity towards wheat. Re-introduction of a functional FgABCC9 gene into ΔFgABCC9 recovered the phenotypes of the wild type strain. Transgenic expression of FgABCC9 in Arabidopsis thaliana increased the accumulation of SA in its leaves without activating SA signaling, which suggests that FgABCC9 functions as an SA exporter. Taken together, FgABCC9 encodes an ABC exporter, which is critical for fungal exportation of SA, response to tebuconazole, mycelial growth, and pathogenicity towards wheat.

scholarly journals Fusarium graminearum Isolates from Wheat and Maize in New York Show Similar Range of Aggressiveness and Toxigenicity in Cross-Species Pathogenicity Tests

2015 ◽  
Vol 105 (4) ◽  
pp. 441-448 ◽  
Author(s):  
Paulo R. Kuhnem ◽  
Emerson M. Del Ponte ◽  
Yanhong Dong ◽  
Gary C. Bergstrom
Keyword(s):  
New York ◽  
Fusarium Graminearum ◽  
Rank Order ◽  
Ear Rot ◽  
Head Blight ◽  
Mycotoxin Production ◽  
Pathogenicity Tests ◽  
Similar Range ◽  
Maize Kernels ◽  
Wheat Kernels

This study aimed to assess whether pathogenic Fusarium graminearum isolates from wheat and maize were more aggressive on their host of origin and whether aggressiveness was influenced further by B-trichothecene chemotype. Fifteen isolates were selected from a contemporary collection of isolates surveyed in New York in 2011 to 2012 to represent diversity of host of origin and chemotype. Three pathogenicity assays were used to evaluate and compare these isolates. Fusarium head blight (FHB) severity and trichothecene production in wheat, and maize seedling blight were evaluated in greenhouse inoculation experiments, and Gibberella ear rot (GER) severity and trichothecene production were evaluated in maize ears inoculated in the field. Our results showed among F. graminearum isolates a wide variation in aggressiveness and mycotoxin production toward wheat and maize and these isolates could not be structured by their host of origin or by chemotype. Moreover, aggressiveness rank order changed according to the host/organ evaluated. This indicates that relative susceptibility at the seedling stage may not predict susceptibility of ears. Significant correlations were observed of total trichothecenes (deoxynivalenol [DON] and its acetylated derivatives) produced with FHB and GER severity on wheat and maize, respectively. One isolate did not produce DON or ADON in wheat or maize kernels, yet was aggressive on both hosts. Nine of the fifteen isolates produced small amounts of zearalenone (ZON) in maize kernels, but not in wheat kernels, and ZON level was not correlated with GER severity. F. graminearum isolates from New York showed wide variation in aggressiveness and mycotoxin production toward susceptible wheat and maize. Neither host of origin nor trichothecene chemotype appeared to structure the populations we sampled.

scholarly journals Fitness traits of deoxynivalenol and nivalenol-producing Fusarium graminearum species complex strains from wheat

2017 ◽  
Author(s):  
C.P. Nicolli ◽  
F.J. Machado ◽  
P. Spolti ◽  
E.M. Del Ponte
Keyword(s):  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Species Complex ◽  
Head Blight ◽  
Fitness Traits ◽  
Fusarium Graminearum Species Complex ◽  
Important Trait ◽  
South Of Brazil ◽  
Species Specific ◽  
Moderately Resistant

AbstractFusarium graminearum of the 15-acetyl(A)deoxynivalenol(D0N) chemotype is the main cause of Fusarium head blight (FHB) of wheat in south of Brazil. However, 3-ADON and nivalenol(NIV) chemotypes have been found in other members of the species complex causing FHB in wheat. To improve our understanding of the pathogen ecology, we assessed a range of fitness-related traits in a sample of 30 strains representatives of 15-ADON (F. graminearum), 3-ADON (F. cortaderiae and F. austroamericanum) and NIV (F. meridionale and F. cortaderiae). These included: perithecia formation on three cereal-based substrates, mycelial growth at two suboptimal temperatures, sporulation and germination, pathogenicity towards a susceptible and a moderately resistant cultivar and sensitivity to tebuconazole. The most important trait favoring F. graminearum was its 2x higher sexual fertility (> 40% PPI = perithecia production index) than the other species (< 30% PPI); PPI varied among substrates (maize > rice > wheat). In addition, sensitivity to tebuconazole appeared lower in F. graminearum which had the only strain with EC50 > 1 ppm. In the pathogenicity assays, the DON-producers were generally more aggressive (1.5 to 2x higher final severity) towards the two cultivars, with 3-ADON or 15-ADON leading to higher area under the severity curve than the NIV strains in the susceptible and moderately resistant cv., respectively. There was significant variation among strains of a same species with regards asexual fertility (mycelial growth, macroconidia production and germination), which suggest a strain-rather than a species-specific differences. These results contribute new knowledge to improve our understanding of the pathogen-related traits that may explain the dominance of certain members of the species complex in specific wheat agroecosystems.

scholarly journals Antifungal Activity of Quinofumelin against Fusarium graminearum and Its Inhibitory Effect on DON Biosynthesis

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 348
Author(s):  
Qian Xiu ◽  
Lianyu Bi ◽  
Haorong Xu ◽  
Tao Li ◽  
Zehua Zhou ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fusarium Graminearum ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Marker Gene ◽  
Economic Loss ◽  
Inhibitory Effect ◽  
Head Blight ◽  
Excellent Control

Fusarium graminearum, causal agent of Fusarium head blight (FHB), causes a huge economic loss. No information is available on the activity of quinofumelin, a novel quinoline fungicide, against F. graminearum or other phytopathogens. In this study, we used mycelial growth and spore germination inhibition methods to determine the inhibitory effect of quinofumelin against F. graminearum in vitro. The results indicated that quinofumelin excellently inhibited mycelial growth and spore germination of F. graminearum, with the average EC50 values of 0.019±0.007 μg/mL and 0.087 ± 0.024 μg/mL, respectively. In addition, we found that quinofumelin could significantly decrease deoxynivalenol (DON) production and inhibit the expression of DON-related gene TRI5 in F. graminearum. Furthermore, we found that quinofumelin could disrupt the formation of Fusarium toxinsome, a structure for producing DON. Western blot analysis demonstrated that the translation level of TRI1, a marker gene for Fusarium toxinsome, was suppressed by quinofumelin. The protective and curative assays indicated that quinofumelin had an excellent control efficiency against F. graminearum on wheat coleoptiles. Taken together, quinofumelin exhibits not only an excellent antifungal activity on mycelial growth and spore germination, but also could inhibit DON biosynthesis in F. graminearum. The findings provide a novel candidate for controlling FHB caused by F. graminearum.

scholarly journals Resistance to Fluopicolide and Propamocarb and Baseline Sensitivity to Ethaboxam Among Isolates of Pseudoperonospora cubensis From the Eastern United States

Plant Disease ◽  
2018 ◽  
Vol 102 (8) ◽  
pp. 1619-1626 ◽  
Author(s):  
A. Thomas ◽  
K. N. Neufeld ◽  
K. W. Seebold ◽  
C. A. Braun ◽  
M. R. Schwarz ◽  
...  
Keyword(s):  
United States ◽  
New York ◽  
Leaf Disc ◽  
The United States ◽  
Resistant Isolate ◽  
Pseudoperonospora Cubensis ◽  
Eastern United States ◽  
Baseline Sensitivity ◽  
Highly Sensitive ◽  
Sensitive Isolate

Chemical control is currently the most effective method for controlling cucurbit downy mildew (CDM) caused by Pseudoperonospora cubensis. Most commercial cucurbit cultivars, with the exception of a few new cucumber cultivars, lack adequate disease resistance. Fluopicolide and propamocarb were among the most effective fungicides against CDM in the United States between 2006 and 2009. Since then, reduced efficacy of these two fungicides under field conditions was reported starting around 2013 but occurrence of resistance to fluopicolide and propamocarb in field isolates of P. cubensis had not been established. Thirty-one isolates collected from cucurbits in the eastern United States were tested for their sensitivity to fluopicolide and propamocarb using a leaf disc assay. This same set of isolates and four additional isolates (i.e., 35 isolates) were also used to establish the baseline sensitivity of P. cubensis to ethaboxam, an ethylamino-thiazole-carboxamide fungicide, which was recently granted registration to control CDM in the United States. About 65% of the isolates tested were resistant to fluopicolide with at least one resistant isolate being present in samples collected from 12 of the 13 states in the eastern United States. About 74% of the isolates tested were sensitive to propamocarb with at least one resistant isolate being among samples collected from 8 of the 12 states in the study. The frequency of resistance to fluopicolide and propamocarb was high among isolates collected from cucumber, while the frequency was low among isolates collected from other cucurbit host types. All isolates tested were found to be sensitive to ethaboxam and EC50 values ranged from 0.18 to 3.08 mg a.i./liter with a median of 1.55 mg a.i./liter. The ratio of EC50 values for the least sensitive and the most sensitive isolate was 17.1, indicating that P. cubensis isolates were highly sensitive to ethaboxam. The most sensitive isolates to ethaboxam were collected from New York, North Carolina, and Ohio, while the least sensitive isolates were collected from Georgia, Michigan, and New Jersey. These results show that ethaboxam could be a viable addition to fungicide programs used to control CDM in the United States.

scholarly journals In vitro sensitivity of Fusarium graminearum isolates to fungicides

2014 ◽  
Vol 40 (3) ◽  
pp. 231-247 ◽  
Author(s):  
Aveline Avozani ◽  
Rosane Baldiga Tonin ◽  
Erlei Melo Reis ◽  
Juliane Camera ◽  
Camila Ranzi
Keyword(s):  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Conidial Germination ◽  
Head Blight ◽  
Synthesis Inhibitor ◽  
Quinone Outside Inhibitor ◽  
Ic50 Values ◽  
Dmi Fungicides ◽  
Different Origins

Head blight of wheat is a disease of global importance. In Brazil, it can cause damage of up to 27%. As resistant cultivars are not available yet, short-term disease control relies on the use of fungicides. The first step to reach effective management is to identify potent fungicides. In vitro experiments were conducted to determine the inhibitory concentration 50% (IC50) for mycelial growth or conidial germination, according to the chemical group of fungicides, of five Fusarium graminearum isolates of different origins. The following demethylation inhibitor (DMI) fungicides were tested: epoxiconazole, cyproconazole, metconazole, prochloraz, protioconazole and tebuconazole. In addition, azoxystrobin, kresoxim-methyl, pyraclostrobin and trifloxystrobin were included in the study, representing Quinone outside inhibitor fungicides (QoI), as well as a tubulin synthesis inhibitor, carbendazim and two ready mixtures, trifloxystrobin + tebuconazole or trifloxistrobin + prothioconazole. DMI's showed lower IC50 values compared to the QoI's. For the five tested isolates, in the overall mean, IC50 considering mycelial growth ranged for DMI's from 0.01 mg/L (metconazole, prochloraz and prothioconazole) to 0.12 mg/L (cyproconazole) and considering conidial germination for QoI's from 0.21 mg/L (azoxystrobin) to 1.33 mg/L (trifloxystrobin). The IC50 for carbendazim was 0.07 mg/L. All tested isolates can be considered sensitive to the studied DMI's, although certain differences in sensitivity could be detected between the isolates originating from one same state.

scholarly journals Carbendazim Resistance of Fusarium graminearum From Henan Wheat

Plant Disease ◽  
2019 ◽  
Vol 103 (10) ◽  
pp. 2536-2540 ◽  
Author(s):  
Shengming Liu ◽  
Liuyuan Fu ◽  
Shuan Wang ◽  
Jinpeng Chen ◽  
Jia Jiang ◽  
...  
Keyword(s):  
Point Mutation ◽  
Fusarium Graminearum ◽  
Single Point ◽  
Point Mutations ◽  
Henan Province ◽  
Resistant Isolate ◽  
Head Blight ◽  
Tubulin Gene ◽  
Predominant Type ◽  
Moderately Resistant

Fusarium head blight, also called scab, is caused by Fusarium graminearum and is one of the most important destructive diseases of wheat. The frequency of carbendazim resistance in 1,132 isolates of F. graminearum recovered from fields in different regions of Henan Province in 2016, 2017, and 2018 was determined. A total of 31 F. graminearum isolates resistant to carbendazim were detected, including 30 moderately resistant isolates and one highly resistant isolate. The frequency of resistance of F. graminearum isolates to carbendazim was 2.7%. The range of effective concentration (EC50) values of 1,101 sensitive isolates and 30 moderately resistant isolates was 0.08 to 0.98 μg ml−1 and 2.73 to 13.28 μg ml−1, respectively. The mean ± SD EC50 value was 0.55 ± 0.13 μg ml−1 and 5.61 ± 2.58 μg ml−1, respectively. The EC50 value of the highly resistant isolate was 21.12 μg ml−1. Point mutation types of the carbendazim-resistant isolates were characterized by cloning the β2-tubulin gene of 31 resistant isolates. Three point mutation types at amino acids F167Y, E198Q, and E198L in the β2-tubulin gene of resistant isolates were identified. Among 31 resistant isolates, the frequency of point mutation types in F167Y, E198Q, and E198L of the β2-tubulin gene was 71.0, 25.8, and 3.2%, respectively. The data indicate that F. graminearum has developed resistance to carbendazim in Henan Province, and single point mutations at amino acid F167Y were the predominant type of mutation detected.

scholarly journals Fitness Attributes of Fusarium graminearum Isolates from Wheat in New York Possessing a 3-ADON or 15-ADON Trichothecene Genotype

2014 ◽  
Vol 104 (5) ◽  
pp. 513-519 ◽  
Author(s):  
Pierri Spolti ◽  
Emerson M. Del Ponte ◽  
Jaime A. Cummings ◽  
Yanhong Dong ◽  
Gary C. Bergstrom
Keyword(s):  
New York ◽  
Fusarium Graminearum ◽  
Wheat Cultivar ◽  
Wheat Variety ◽  
Head Blight ◽  
Wheat Kernels ◽  
Ascospore Production

In all, 50 isolates of Fusarium graminearum from wheat spikes in New York, including 25 isolates each of the 15-acetyl-deoxynivalenol (15-ADON) and 3-ADON genotype, were tested to determine whether 3-ADON isolates are more fit for saprophytic survival and pathogenicity on wheat spikes than are 15-ADON isolates. The isolates were characterized and compared for 14 different attributes of saprophytic fitness and pathogenic fitness on a susceptible wheat variety. Isolates of the two genotypes could not be differentiated for most of these traits. Three principle components—ascospore production on corn stalks, total trichothecene amount in wheat kernels, and incidence of diseased spikelets up from the point of inoculation—accounted for 29.4, 18.9, and 10.8% of the variation among the isolates, respectively. A bootstrapping procedure grouped the isolates into two distinct groups, with 27 and 23 isolates each, with isolates from both genotypes represented in similar proportions (15-ADON/3-ADON, n = 14/13 and 11/12). Within the contemporary population of F. graminearum causing wheat head blight in New York, isolates with a 3-ADON genotype did not possess any detectable advantage over isolates with a 15-ADON genotype in saprophytic fitness or in pathogenic fitness on a susceptible wheat cultivar.

scholarly journals In vitro sensitivity reduction of Fusarium graminearum to DMI and QoI fungicides

2014 ◽  
Vol 40 (4) ◽  
pp. 358-364 ◽  
Author(s):  
Aveline Avozani ◽  
Erlei Melo Reis ◽  
Rosane Baldiga Tonin
Keyword(s):  
Fusarium Graminearum ◽  
Mycelial Growth ◽  
Inhibitory Concentration ◽  
Head Blight ◽  
Short Term ◽  
Qoi Fungicides ◽  
Dmi Fungicides ◽  
Fungal Populations ◽  
Demethylation Inhibitor

In Brazil, Fusarium head blight (FHB) affecting wheat can cause up to 39.8% damage. Resistant cultivars are not available yet; thus, short-term disease control relies on the use of fungicides. The first step to improve control is to monitor fungal populations that are sensitivity to chemicals in order to achieve efficient FHB management. In vitro experiments were conducted to evaluate the inhibitory concentration (IC50) of fungicides for both mycelial growth and conidial germination of ten Fusarium graminearum isolates. The following demethylation inhibitor (DMI) fungicides were tested: metconazole, prothioconazole and tebuconazole. In addition, pyraclostrobin and trifloxystrobin were included, representing QoI fungicides, as well as three co-formulations containing metconazole + pyraclostrobin, prothioconazole + trifloxystrobin, and tebuconazole + trifloxystrobin. For mycelial growth, the overall mean IC50 of isolates was: metconazole 0.07, prothioconazole 0.1, and tebuconazole 0.19 mg/L. For the co-formulations, it was: prothioconazole + trifloxystrobin 0.08, tebuconazole + trifloxystrobin 0.12, and metconazole + pyraclostrobin 0.14 mg/L. Regarding spore germination inhibition, IC50 for prothioconazole + trifloxystrobin was 0.06, for tebuconazole + trifloxystrobin, 0.12 mg/L, for QoI alone pyraclostrobin, was 0.09, and for trifloxystrobin, 0.28 mg/L. There was a sensitivity shift among isolates and the highest fungitoxicity to F. graminearum was confirmed for prothioconazole, metconazole and tebuconazole .

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