scholarly journals Sensitivity of Monilinia fructicola from Peach Farms in China to Four Fungicides and Characterization of Isolates Resistant to Carbendazim and Azoxystrobin

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1555-1560 ◽  
Author(s):  
S. N. Chen ◽  
Y. Shang ◽  
Y. Wang ◽  
G. Schnabel ◽  
Y. Lin ◽  
...  
Keyword(s):  
Target Gene ◽  
Brown Rot ◽  
Mean Value ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Amino Acid Mutation ◽  
Disease Symptoms ◽  
Benzimidazole Carbamates ◽  
Production Areas

Brown rot of peach caused by Monilinia fructicola can cause considerable preharvest and postharvest losses in China. Fungicides are increasingly utilized to minimize such losses. Eighty isolates of M. fructicola were collected from commercial peach orchards located in five provinces in China and the sensitivity to carbendazim, azoxystrobin, tebuconazole, and boscalid was determined. Resistance to carbendazim was detected only in the Yunnan province in 15 of 16 isolates. Characterization of carbendazim-resistant isolates revealed stable resistance, no fitness penalty, and negative cross resistance to diethofencarb. Resistant isolates produced disease symptoms on detached fruit sprayed with label rates of formulated carbendazim and possessed the amino acid mutation E198A in β-tubulin. Resistance to azoxystrobin was detected in 3 of 10 isolates from Fujian. In contrast to carbendazim resistance, however, azoxystrobin resistance was unstable, associated with a fitness penalty, and not associated with mutations in the target gene cytochrome b. The concentration at which mycelial growth is inhibited 50% (EC50) values of the azoxystrobin-sensitive isolates were 0.02 to 1.94 μg/ml, with a mean value of 0.54 μg/ml. All isolates were sensitive to tebuconazole, with a mean EC50 value of 0.03 μg/ml. The EC50 values for boscalid were 0.01 to 3.85 μg/ml, with a mean value of 1.02 μg/ml. Our results indicate that methyl benzimidazole carbamates (MBCs), quionon outside inhibitors, demethylation inhibitor fungicides, and succinate dehydrogenase inhibitors are likely to be very effective in controlling brown rot in many peach production areas in China, but that resistance to MBCs is emerging.

scholarly journals Baseline Sensitivity of Monilinia fructicola from China to the DMI Fungicide SYP-Z048 and Analysis of DMI-Resistant Mutants

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 416-422 ◽  
Author(s):  
F. P. Chen ◽  
J. R. Fan ◽  
T. Zhou ◽  
X. L. Liu ◽  
J. L. Liu ◽  
...  
Keyword(s):  
Brown Rot ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Lesion Area ◽  
Site Mutation ◽  
Baseline Sensitivity ◽  
Dmi Fungicides ◽  
Resistant Mutants ◽  
Beijing China

Sterol 14α-demethylase inhibitors (DMIs) continue to be important in the management of brown rot of Monilinia spp. worldwide. In this study, the sensitivity of 100 Monilinia fructicola isolates from four unsprayed orchards and two packinghouses in Beijing, China, to the new DMI fungicide SYP-Z048 was evaluated and ranged from 0.003 to 0.039 and 0.016 to 0.047 μg/ml, respectively. Laboratory mutants resistant to SYP-Z048 were generated using UV irradiation but no mutants occurred spontaneously. Resistance was stable after 10 weekly consecutive transfers on fungicide-free medium. Three parameters, including growth rate, sporulation in vitro, and lesion area, were significantly different when sensitive isolates and resistant mutants were analyzed as groups. Mutants grew more slowly and developed significantly smaller lesions on detached fruit, and their sporulation ability in vitro was reduced. Cross resistance was found between SYP-Z048 and propiconazole (ρ = 0.82, P < 0.0001) but not between SYPZ048 and tridemorph, carbendazim, procymidone, azoxystrobin, or pyrimethanil. SYP-Z048 resistance in mutants exhibiting 50% mycelial growth inhibition values greater than 0.3 μg/ml was correlated with the presence of a mutation in the CYP51 gene that encodes the target protein for DMI fungicides. The mutation caused an amino acid change from tyrosine to phenylalanine at position 136 (Y136F). To our knowledge, this is the first baseline sensitivity of M. fructicola collected from China to a DMI fungicide. The inability of M. fructicola to generate spontaneous DMI-resistant mutants coupled with reduced fitness of Y136F mutants can explain why this target site mutation has not yet emerged as a DMI fungicide resistance determinant in M. fructicola field populations worldwide.

scholarly journals Cross-Resistance Among Demethylation Inhibitor Fungicides With Brazilian Monilinia fructicola Isolates as a Foundation to Discuss Brown Rot Control in Stone Fruit

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2843-2850
Author(s):  
Pamela Suellen Salvador Dutra ◽  
Paulo S. F. Lichtemberg ◽  
Maria Bernat Martinez ◽  
Themis J. Michailides ◽  
Louise Larissa May De Mio
Keyword(s):  
Brown Rot ◽  
Lesion Size ◽  
Stone Fruit ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Wild Type ◽  
Specific Test ◽  
Allele Specific ◽  
Fruit Orchards ◽  
Demethylation Inhibitor

Despite the resistance problems in Monilinia fructicola, demethylation inhibitor fungicides (DMIs) are still effective for the disease management of brown rot in commercial stone fruit orchards in Brazil. This study aims to investigate the sensitivity of M. fructicola isolates and efficiency of DMIs to reduce brown rot. A set of 93 isolates collected from Brazilian commercial orchards were tested for their sensitivities to tebuconazole, propiconazole, prothioconazole, and myclobutanil. The isolates were analyzed separately according to the presence or absence of the G461S mutation in MfCYP51 gene, determined by allele-specific test. The mean EC50 values for G461S mutants and wild-type isolates were respectively 8.443 and 1.13 µg/ml for myclobutanil, 0.236 and 0.026 µg/ml for propiconazole, 0.115 and 0.002 µg/ml for prothioconazole, and 1.482 and 0.096 µg/ml for tebuconazole. The density distribution curves of DMI sensitivity for both genotypes showed that myclobutanil and prothioconazole curves were mostly shifted toward resistance and sensitivity, respectively. Incomplete cross-resistance was detected among propiconazole and tebuconazole in both wild-type (r = 0.45) and G461S (r = 0.38) populations. No cross-sensitivity was observed among wild-type isolates to prothioconazole and the others DMIs tested. Fungicide treatments on detached fruit inoculated with M. fructicola genotypes showed significant DMI efficacy differences when fruit were inoculated with wild-type and G461S isolates. Protective applications with prothioconazole were more effective for control of both G461S and wild-type isolates compared with tebuconazole. Curative applications with tebuconazole were most effective in reducing the incidence and lesion size of G461S isolates. Sporulation occurred only for G461S isolates treated with tebuconazole under curative and preventative treatments. The differences found among the performance of triazoles against M. fructicola isolates will form the basis for recommendations of rational DMI usage to control brown rot in Brazil.

scholarly journals First Report of the β-Tubulin E198A Mutation Conferring Resistance to Methyl Benzimidazole Carbamates in European Isolates of Monilinia fructicola

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 497-497 ◽  
Author(s):  
J. Weger ◽  
M. Schanze ◽  
M. Hilber-Bodmer ◽  
T. H. M. Smits ◽  
A. Patocchi
Keyword(s):  
South Carolina ◽  
Molecular Mechanisms ◽  
Brown Rot ◽  
The United States ◽  
Monilinia Fructicola ◽  
Tubulin Gene ◽  
First Report ◽  
Benzimidazole Carbamates ◽  
High Level ◽  
Β Tubulin

The causal agent of brown rot on stone and pome fruits, Monilinia fructicola (G. Wint.), is a quarantine pathogen in Europe. It has been detected in Austria (later eradicated), Spain, the Czech Republic, Italy, Germany, and Switzerland (1). In the United States and other countries, M. fructicola isolates were reported to show resistance to different classes of fungicides, including methyl benzimidazole carbamates (MBC) (2). Lichou et al. (2) reported the presence of isolates resistant to the MBC carbendazim in France, but the mechanisms inducing MBC resistance in these isolates were not studied. Ma et al. (3) in California, and more recently, Zhu et al. (4) in South Carolina, demonstrated that the molecular mechanisms accounting for low and high levels of resistance to MBC fungicides in M. fructicola isolates were the mutations H6Y and E198A, respectively, in the β-tubulin gene. Four M. fructicola isolates each from Italy, France, Spain, and Switzerland (16 isolates total), all having an unknown level of MBC resistance, were selected. In each isolate, the section of the β-tubulin gene containing the two potentially mutant codons was PCR-amplified with the primers TubA and TubR1 (3) and the amplicons were sequenced directly. Sequence analysis revealed the amino acid histidine (H) at codon 6 in all the isolates, which would not predict MBC resistance, while alanine (A) at codon 198 (the mutation predictive of a high level of MBC resistance) was found in all isolates from Spain and Switzerland and in three isolates each from France and Italy. A representative sequence of the four identical partial β-tubulin gene sequences from the Swiss isolates was submitted to GenBank under the Accession No. HQ709265. All isolates were tested in a potato dextrose agar (PDA) petri dish assay for resistance to the MBC fungicide thiophanate-methyl (Nippon Soda Co., Ltd., Tokyo, Japan) at the discriminatory dose of 50 μg/ml (4). All isolates with the E198A mutation were able to grow on the media, while the two isolates without the E198A mutation were not able to grow. The result indicated that most isolates had a high level of resistance to the MBC fungicide. To our knowledge, this is the first report of the presence of the E198A mutation conferring resistance to MBC fungicides in European isolates of M. fructicola. As the mutation appears to be widely distributed, we anticipate that MBC fungicides may be ineffective at controlling brown rot in countries with occurrence of M. fructicola. References: (1) M. Hilber-Bodmer et al. Plant Dis. 94:643, 2010. (2) J. Lichou et al. Phytoma 547:22, 2002. (3) Z. H. Ma et al. Appl. Environ. Microbiol. 69:7145, 2003. (4) F. X. Zhu et al. Plant Dis. 94:1511, 2010.

scholarly journals Characterization of M. laxa and M. fructigena isolates from Hungary with MP-PCR

2012 ◽  
Vol 39 (No. 3) ◽  
pp. 116-122 ◽  
Author(s):  
Sz. Sződi ◽  
H. Komjáti ◽  
Gy. Turóczi
Keyword(s):  
Genetic Diversity ◽  
Brown Rot ◽  
Monilinia Fructicola ◽  
Monilinia Laxa ◽  
Stone Fruits ◽  
Monilinia Fructigena ◽  
Population Structure Analysis ◽  
Total Genetic Diversity ◽  
Biological Methods

Monilinia laxa (Monilia laxa), Monilinia fructicola (Monilia fructicola) and Monilinia fructigena (Monilia fructigena) are the causal agents of brown rot on pome and stone fruits in Hungary. Forty-five isolates collected from different hosts, different years in several orchards were used for characterization of the M. laxa and M. fructigena population in Hungary. The isolates were identified on species level based on morphological and molecular biological methods; out of these 24 were M. laxa, 20 were M. fructigena and 1 was M. fructicola. Populations of the three Monilinia species were studied with microsatellite primers and the degree of genetic diversity within the species was measured. The population structure analysis revealed that genetic diversity within M. laxa subpopulations was H<sub>S</sub>= 0.1599, while within M. fructigena subpopulations was H<sub>S</sub>= 0.2551. The total genetic diversity was H<sub>T</sub>= 0.3846, while genetic diversity between M. laxa and M. fructigena subpopulations was D<sub>ST</sub>= 0.1771. No clustering relationship was observed among isolates by the different years or hosts.

scholarly journals First Report of the β-tubulin E198A Allele for Fungicide Resistance in Monilinia fructicola from South Carolina

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1511-1511 ◽  
Author(s):  
F. X. Zhu ◽  
P. K. Bryson ◽  
A. Amiri ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
East Coast ◽  
Brown Rot ◽  
Petri Dish ◽  
Monilinia Fructicola ◽  
Tubulin Gene ◽  
First Report ◽  
Additional Control ◽  
Benzimidazole Carbamates ◽  
Β Tubulin

Resistance to methyl benzimidazole carbamates (MBCs) in Monilinia fructicola, the causal agent of brown rot of stone fruits, is known to be present in South Carolina peach orchards, but the molecular mechanism of resistance has not been investigated. Nine isolates were collected from peach in five counties in South Carolina and examined in petri dish assays on potato dextrose agar (PDA) for resistance to the MBC fungicide thiophanate-methyl (Topsin-M 70WP; Ceraxagri, King of Prussia, PA) at the discriminatory dose of 50 μg/ml. Isolates that grew on the fungicide-amended medium were considered highly resistant (HR). The β-tubulin gene from four sensitive (S) and five HR M. fructicola isolates was PCR-amplified with primer pair TubA and TubR1 as described previously (1). Sequence analysis revealed several silent mutations in introns and exons in S and HR isolates and the presence of the previously described E198A allele in HR but not S isolates (1). Nucleotide sequences of the β-tubulin gene from three S (BS, S2, MfEgpc1) and two HR isolates (MfPdt6 and BR2) were submitted to GenBank under accession numbers HM051379, HM051380, HM051381, HM051382, and HM051383, respectively. To our knowledge, this is the first report of the E198A in M. fructicola isolates from South Carolina and the East Coast. This allele is responsible for high levels of MBC resistance in M. fructicola (1). A previously reported PCR-based method using primers HRF+HRR designed to detect the E198A mutation in M. fructicola HR isolates (1) was improved by adding primer TR739 (5′-TCA CGA CGA ACA ACA TCA AGA-3′) to the PCR cocktail. This additional internal primer amplified a 222-bp fragment from all S and HR isolates and therefore provided a useful, additional control. The confirmation of the E198A allele in M. fructicola isolates provides another useful tool to detect MBC resistance in commercial peach orchards in South Carolina. Reference: (1) Z. H. Ma et al. Appl. Environ. Microbiol. 69:7145, 2003.

scholarly journals Reduced Sensitivity in Monilinia fructicola Field Isolates from South Carolina and Georgia to Respiration Inhibitor Fungicides

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 737-743 ◽  
Author(s):  
A. Amiri ◽  
P. M. Brannen ◽  
G. Schnabel
Keyword(s):  
South Carolina ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Brown Rot ◽  
Conidial Germination ◽  
Cross Resistance ◽  
Monilinia Fructicola ◽  
Significant Difference

Quinone outside inhibitor (QoI) and succinate dehydrogenase inhibitor (SdhI) fungicides are respiration inhibitors (RIs) used for preharvest control of brown rot of stone fruit. Both chemical classes are site-specific and, thus, prone to resistance development. Between 2006 and 2008, 157 isolates of Monilinia fructicola collected from multiple peach and nectarine orchards with or without RI spray history in South Carolina and Georgia were characterized based upon conidial germination and mycelial growth inhibition for their sensitivity to QoI fungicides azoxystrobin and pyraclostrobin, SdhI fungicide boscalid, and a mixture of pyraclostrobin + boscalid. There was no significant difference (P = 0.05) between EC50 values for inhibition of conidial germination versus mycelial growth. The mean EC50 values based upon mycelial growth tests for 25 isolates from an orchard without RI-spray history were 0.15, 0.06, 2.23, and 0.09 μg/ml for azoxystrobin, pyraclostrobin, boscalid, and pyraclostrobin + boscalid, respectively. The respective mean EC50 values for 76 isolates from RI-sprayed orchards in South Carolina were 0.9, 0.1, 10.7, and 0.13 μg/ml and for 56 isolates from RI-sprayed orchards in Georgia were 1.2, 0.1, 8.91, and 0.17 μg/ml. Overall, mean EC50 values of populations from RI-sprayed orchards increased three-, two-, five-, and twofold between 2006 and 2008 for azoxystrobin, pyraclostrobin, boscalid, and pyraclostrobin + boscalid, respectively. A subset of 10 M. fructicola isolates representing low and high EC50 values for azoxystrobin, boscalid, and boscalid + pyraclostrobin was selected for a detached fruit assay to determine disease incidence and severity following protective treatments of formulated RI fungicides at label rates. Brown rot incidence was greater than 50% when fruit were inoculated with isolates having EC50 values of 2, 4, and 0.6 μg/ml for azoxystrobin, boscalid, and pyraclostrobin + boscalid, respectively. Pyraclostrobin failed to control any of the isolates tested in detached fruit assays. Based on minimum inhibitory concentration and brown rot incidence data, we recommend using 3 and 0.75 μg/ml as discriminatory doses to distinguish between sensitive isolates and those with reduced sensitivity to azoxystrobin and pyraclostrobin + boscalid, respectively. Results from our in vitro and in vivo assays indicate a shift toward reduced sensitivity in M. fructicola from the southeastern United States. No cross-resistance was observed between the QoI and the SdhI fungicides, which implies that rotation or tank mixtures of these two chemical classes can be used as a resistance management strategy.

scholarly journals Characterization of Monilinia fructicola Associated with Brown Rot of Cherry Fruit in Korea

2014 ◽  
Vol 42 (4) ◽  
pp. 353-356 ◽  
Author(s):  
Hyo-Won Choi ◽  
Sung Kee Hong ◽  
Young Kee Lee ◽  
Young Ju Nam ◽  
Jae Guem Lee ◽  
...  
Keyword(s):  
Brown Rot ◽  
Monilinia Fructicola

scholarly journals Halogenated Volatile Organic Compounds in Water Samples and Inorganic Elements Levels in Ores for Characterizing a High Anthropogenic Polluted Area in the Northern Latium Region (Italy)

2021 ◽  
Vol 18 (4) ◽  
pp. 1628
Author(s):  
Mario Vincenzo Russo ◽  
Ivan Notardonato ◽  
Alberto Rosada ◽  
Giuseppe Ianiri ◽  
Pasquale Avino
Keyword(s):  
Organic Compounds ◽  
Mean Value ◽  
Greenhouse Crops ◽  
River Waters ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
High Concentrations ◽  
Very High ◽  
Inorganic Fraction

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid–liquid extraction and static headspace) followed by gas chromatography–electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L−1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g−1), antimony (77.7 µg g−1), strontium (12,039 µg g−1) and zinc (103 µg g−1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g−1): the levels found in this paper (ranging between 1 and 5100 µg g−1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.

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