scholarly journals Phenotypic Characterization of Multifungicide Resistance in Botrytis cinerea Isolates from Strawberry Fields in Florida

Plant Disease ◽  
2013 ◽  
Vol 97 (3) ◽  
pp. 393-401 ◽  
Author(s):  
A. Amiri ◽  
S. M. Heath ◽  
N. A. Peres

Chemical control has always been essential for the management of gray mold, caused by Botrytis cinerea, to ensure sustainable strawberry production. However, lack of knowledge about actual resistance development may have disastrous consequences and lead to severe epidemics such as the one that affected several strawberry fields in 2012 in Florida. In this study, we tested 392 isolates collected from Florida strawberry fields between 2010 and 2012 for their sensitivity to boscalid (Bosc), a succinate dehydrogenase inhibitor (SdhI); pyraclostrobin, a quinone outside inhibitor (QoI); boscalid + pyraclostrobin (Pristine); fenhexamid, a hydroxyanilide (Hyd); pyrimethanil and cyprodinil, anilinopyrimidines; fludioxonil, a phenylpyrrole; and fludioxonil + cyprodinil (Switch). The respective resistance frequencies for boscalid, pyraclostrobin, Pristine, fenhexamid, cyprodinil, and pyrimethanil were 85.4, 86.5, 86.0, 44.4, 52.7, and 59.5%. Overall, 17.8 and 19.8% of isolates showed reduced sensitivity to fludioxonil and Switch, respectively. All fungicides sprayed preventively on detached strawberry fruit failed to control isolates with high levels of resistance to each fungicide except for fludioxonil and Switch. Four phenotypes with multifungicide resistance (MFR) were detected in B. cinerea populations from Florida. Isolates resistant to one fungicide (FR1), two (MFR2), three (MFR3), and four (MFR4) fungicides from different chemical groups represented 5.9, 28.6, 41.8, and 23.7% of the total resistant population, respectively. The MFR3 isolates were predominant and contained two subpopulations, the Bosc-QoI-APR isolates (56.5%) and the Bosc-QoI-HydR isolates (40.6%). In addition to reporting on very highly resistant populations to boscalid and QoI fungicides, we show evidence for a widespread multifungicide resistance to B. cinerea that warrants immediate implementation of novel management strategies to impede the development of more resistant populations.

2021 ◽  
Author(s):  
Lincoln A. Harper ◽  
Scott Paton ◽  
Barbara Hall ◽  
Suzanne McKay ◽  
Richard P. Oliver ◽  
...  

AbstractGray mold, caused by Botrytis cinerea, is an economically important disease of grapes in Australia and across grape growing regions worldwide. Control of this disease relies heavily on canopy management and the application of single site fungicides. Fungicide application can lead to the selection of fungicide resistant B. cinerea populations, which has an adverse effect on the chemical control of the disease. Characterising the distribution and severity of resistant B. cinerea populations is needed to inform resistance management strategies. In this study, 725 isolates were sampled from 75 Australian vineyards during 2013 – 2016 and were screened against seven fungicides with different MOAs. The resistance frequencies for azoxystrobin, boscalid, fenhexamid, fludioxonil, iprodione, pyrimethanil and tebuconazole were 5, 2.8, 2.1, 6.2, 11.6, 7.7 and 2.9% respectively. Nearly half of the resistant isolates (43.7%) were resistant to more than one of the fungicides tested. The frequency of vineyards with at least one isolate simultaneously resistant to 1, 2, 3, 4 or 5 fungicides was 19.5, 7.8, 6.5, 10.4 and 2.6%.Resistance was associated with previously published genotypes in CytB (G143A), SdhB (H272R/Y), Erg27 (F412S), Mrr1 (D354Y), Os1 (I365S, N373S + Q369P, I365S + D757N) and Pos5 (P319A, L412F). Expression analysis was used to characterise fludioxonil resistant isolates exhibiting overexpression (6.3 - 9.6-fold) of the ABC transporter encoded by AtrB (MDR1 phenotype). Novel genotypes were also described in Mrr1 (S611N, D616G) and Cyp51 (P357S). Resistance frequencies were lower when compared to most previously published surveys of both grape and non-grape B. cinerea resistance. Nonetheless, continued monitoring of critical chemical groups used in Australian vineyards is recommended.


2014 ◽  
Vol 104 (8) ◽  
pp. 859-864 ◽  
Author(s):  
Marc Bardin ◽  
Véronique Decognet ◽  
Philippe C. Nicot

Although Botrytis cinerea is known for its ability to produce high amounts of spores on diseased plants, enabling it to complete rapidly numerous developmental cycles in favorable environments, population genetics studies of this fungus indicate enormous diversity and limited clonal spread. Here, we report an exception to this situation in the settings of commercial tomato greenhouses. The genotypic characterization of 712 isolates collected from the air and from diseased plants, following the development of gray mold epidemics in four greenhouses in southern France, revealed the presence of a few predominant genotypes in a background of highly diverse populations. The comparison of genotypic profiles for isolates collected in the air or on the plants was compatible with the hypothesis of an entry in the greenhouse of substantial amounts of inoculum from the outside environment but it also highlighted the importance of secondary inoculum produced within the crop. The overall results of this work suggest that sporulation could be an important target for disease management strategies in the greenhouse.


2017 ◽  
Vol 107 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Wayne M. Jurick ◽  
Otilia Macarisin ◽  
Verneta L. Gaskins ◽  
Eunhee Park ◽  
Jiujiang Yu ◽  
...  

Botrytis cinerea causes gray mold and is an economically important postharvest pathogen of fruit, vegetables, and ornamentals. Fludioxonil-sensitive B. cinerea isolates were collected in 2011 and 2013 from commercial storage in Pennsylvania. Eight isolates had values for effective concentrations for inhibiting 50% of mycelial growth of 0.0004 to 0.0038 μg/ml for fludioxonil and were dual resistant to pyrimethanil and thiabendazole. Resistance was generated in vitro, following exposure to a sublethal dose of fludioxonil, in seven of eight dual-resistant B. cinerea isolates. Three vigorously growing B. cinerea isolates with multiresistance to postharvest fungicides were further characterized and found to be osmosensitive and retained resistance in the absence of selection pressure. A representative multiresistant B. cinerea strain caused decay on apple fruit treated with postharvest fungicides, which confirmed the in vitro results. The R632I mutation in the Mrr1 gene, associated with fludioxonil resistance in B. cinerea, was not detected in multipostharvest fungicide-resistant B. cinerea isolates, suggesting that the fungus may be using additional mechanisms to mediate resistance. Results from this study show for the first time that B. cinerea with dual resistance to pyrimethanil and thiabendazole can also rapidly develop resistance to fludioxonil, which may pose control challenges in the packinghouse environment and during long-term storage.


Plant Disease ◽  
2021 ◽  
Author(s):  
Hafiz Muhammad Usman ◽  
Qin Tan ◽  
Mohammad Mazharul Karim ◽  
Muhammad Adnan ◽  
Weixiao Yin ◽  
...  

Anthracnose, mainly caused by Colletotrichum gloeosporioides species complex including C. fructicola and C. siamense, is a devastating disease of peach. The chemical control has been widely used for years and management failures have increased towards commonly used fungicides. Therefore, screening of sensitivity of Colletotrichum spp. to fungicides with different modes of action is needed to make proper management strategies for peach anthracnose. In this study, sensitivity of 80 isolates of C. fructicola and C. siamense was screened for pyraclostrobin, procymidone, prochloraz and fludioxonil based on mycelial growth inhibition at discriminatory doses. Results showed that C. fructicola and C. siamense isolates were highly resistant to procymidone and fludioxonil with 100% resistance frequencies to both fungicides, but sensitive to prochloraz, i.e., no resistant isolates were found. For pyraclostrobin, 74% of C. fructicola isolates showed high resistance and 26 % were low resistant, all of the C. siamense isolates were low resistant. No positive cross-resistance was observed between pyraclostrobin and azoxystrobin, even they are members of the same quinone outside inhibitor (QoI) fungicide group, and between pyraclostrobin and non-QoIs. Resistant isolates to QoI fungicides were evaluated for the fitness penalty. Results showed that no significant differences except for mycelial growth rates were detected between highly resistant and low-resistant isolates of C. fructicola. Molecular characterization of Cyt b gene revealed that the G143A point mutation was the determinant of the high resistance in C. fructicola. This study demonstrated the current resistance status of C. fructicola and C. siamense to different fungicides and their future perspectives. Demethylation inhibitor (DMI) fungicides are the best option among different chemicals to control peach anthracnose in China.


2018 ◽  
Vol 7 (3) ◽  
pp. 131-131
Author(s):  
Raees Ahmed ◽  
Amjad S. Gondal ◽  
Muhammad Tariq Khan ◽  
Shazia Shahzaman ◽  
Sajjad Hyder

Gray mold caused by Botrytis cinerea is an important disease that attacks fruits, leaves and twigs of peach. Peach is grown on an area of 18,008 ha with an average production of 72,085 tons per year in Pakistan (FAO, 2017). During May 2017, brown spots on 33% of the peach fruits examined were observed in Swat district of KPK province of Pakistan. Infected fruits were incubated at 25±2 °C in a humid chamber resulted in greyish mycelial growth with light brown lesions. Hyphal growths on infected fruits were cultured on PDA media and purified by hyphal tip method. Morphologically whitish grey growth was observed on PDA and later on dark sclerotia were observed after 6-7 days of incubation. Hyphae were found septate with branched hyaline conidiophores having a bunch of ovoid conidia at their tips. Further confirmations were done by amplifying internal transcribed spacer regions (Andrew et al., 2009) and glyceraldehyde-3-phosphate dehydrogenase (G3PDH) region of the isolates (Li et al., 2012). Amplicons sequenced from Macrogen Korea were blasted and submitted in NCBI showed that ITS sequences (Accessions MH049690 and MH049691) were 99% identical with already reported (MG878388 and MG654661) sequences and the G3PDH gene sequences (Accessions MH560352 and MH560353) were 99 % identical with already reported (Accessions MG204876) sequences of B. cinerea. Pathogenicity was confirmed on healthy peach fruits disinfected with 50% ethanol, inoculated by placing a plug of about 1cm2 taken from the edge of actively growing B. cinerea isolate (BTS-16). Fruits were incubated at 25±2 °C in a humid chamber (Abata et al., 2016). A set of healthy fruits mock-inoculated with a plug of agar medium were used as control. Three days after inoculation, inoculated fruits showed sunken lesions with cottony greyish mycelial growth on their surface. Fungus isolated from these infections was re-confirmed as B. cinerea. Conducive environment for the disease progression in nearby areas can result into a huge loss in peach produce so there is a need to devise management strategies to cope with the pathogen. This is the first report of gray mold disease of peach caused by B. cinerea from Pakistan. 


Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2087-2093 ◽  
Author(s):  
S. Saito ◽  
T. J. Michailides ◽  
C. L. Xiao

Gray mold caused by Botrytis cinerea is a major postharvest disease of blueberry grown in the Central Valley of California and western Washington State. Sensitivities to boscalid, cyprodinil, fenhexamid, fludioxonil, and pyraclostrobin, representing five different fungicide classes, were examined for 249 (California) and 106 (Washington) B. cinerea isolates recovered from decayed blueberry fruit or flowers. In California and Washington, 7 and 17 fungicide-resistant phenotypes, respectively, were detected: 66 and 49% of the isolates were resistant to boscalid, 20 and 29% were moderately resistant to cyprodinil, 29 and 29% were resistant to fenhexamid, and 66 and 55% were resistant to pyraclostrobin. All isolates from California were sensitive to fludioxonil, whereas 70% of the isolates from Washington showed reduced sensitivity to fludioxonil. In California, 26 and 30% of the isolates were resistant to two and three classes of fungicides, respectively. In Washington, 31, 14, 16, and 9% of the isolates were resistant to two, three, four, and five classes of fungicides, respectively. Inherent risk of the development of resistance to quinone outside inhibitor (QoI) fungicides was assessed by detecting the presence of the Bcbi-143/144 intron in gene cytb. The intron was detected in 11.8 and 40% of the isolates in California and Washington, respectively, suggesting that the risk of QoI resistance is higher in California than in Washington. On detached blueberry fruit inoculated with 11 isolates exhibiting different fungicide-resistant phenotypes, most fungicides failed to control gray mold on fruit inoculated with the respective resistant phenotypes but the mixture of cyprodinil and fludioxonil was effective against all fungicide-resistant phenotypes tested. Our findings would be useful in designing and implementing fungicide resistance management spray programs for control of gray mold in blueberry.


2015 ◽  
Vol 105 (4) ◽  
pp. 424-432 ◽  
Author(s):  
Dolores Fernández-Ortuño ◽  
Anja Grabke ◽  
Xingpeng Li ◽  
Guido Schnabel

Gray mold, caused by the fungal pathogen Botrytis cinerea, is one of the most destructive diseases of small fruit crops and control is largely dependent on the application of fungicides. As part of a region-wide resistance-monitoring program that investigated 1,890 B. cinerea isolates from 189 fields in 10 states of the United States, we identified seven isolates (0.4%) from five locations in four different states with unprecedented resistance to all seven Fungicide Resistance Action Committee (FRAC) codes with single-site modes of action including FRAC 1, 2, 7, 9, 11, 12, and 17 registered in the United States for gray mold control. Resistance to thiophanate-methyl, iprodione, boscalid, pyraclostrobin, and fenhexamid was based on target gene mutations that conferred E198A and F200Y in β-tubulin, I365N/S in Bos1, H272R/Y in SdhB, G143A in Cytb, and T63I and F412S in Erg27. Isolates were grouped into MDR1 and MDR1h phenotypes based on sensitivity to fludioxonil and variations in transcription factor mrr1. MDR1h isolates had a previously described 3-bp deletion at position 497 in mrr1. Expression of ABC transporter atrB was increased in MDR1 isolates but highest in MDR1h isolates. None of the isolates with seven single resistances (SR) had identical nucleotide variations in target genes, indicating that they emerged independently. Multifungicide resistance phenotypes did not exhibit significant fitness penalties for the parameters used in this study, but MDR1h isolates produced more sclerotia at low temperatures and exhibited increased sensitivity to salt stress. In this study we show that current resistance management strategies have not been able to prevent the geographically independent development of resistance to all seven site-specific fungicides currently registered for gray mold control in the United States and document the presence of MDR1h in North America.


2018 ◽  
Vol 108 (11) ◽  
pp. 1287-1298 ◽  
Author(s):  
O. Kozhar ◽  
T. L. Peever

Botrytis cinerea, causal agent of gray mold, is one of the most important pathogens affecting raspberry in the U.S. Pacific Northwest and worldwide. Fungicides are currently applied to control the disease starting from 5 to 10% bloom and continuing on a calendar basis throughout the season rather than according to inoculum level or infection risk primarily because the disease cycle on red raspberry is poorly understood. Botrytis cinerea was isolated from raspberry flowers and fruit sampled at seven developmental stages during each of 2015 and 2016 in a northwestern Washington raspberry field untreated with fungicides. Incidence of colonization of flowers was low (15% of total sampled flowers), but increased as fruit developed, and peaked in mature fruit (67% of total sampled fruit). In the early stages of flower development, B. cinerea recovery was greatest from the carpel (80% of carpels colonized) compared with other floral organs. As fruit matured, additional floral parts were colonized by B. cinerea, possibly facilitating secondary internal or external infections of mature fruit. Average weekly minimum air temperature, average weekly night air temperature, cumulative rain, average weekly leaf wetness percentage, and duration of leaf wetness >90% were significantly positively correlated with B. cinerea colonization of raspberry in NW Washington during two seasons of this study. Our data does not support the hypothesis that the bloom period is the critical window for B. cinerea colonization of red raspberry and suggest that later colonization of developing fruit may be more important for gray mold development on raspberry. The outcomes of this research provide useful information for improvement of gray mold disease management strategies for red raspberry in NW Washington and elsewhere.


2021 ◽  
Vol 9 (2) ◽  
pp. 266
Author(s):  
Weizhen Wang ◽  
Yuan Fang ◽  
Muhammad Imran ◽  
Zhihong Hu ◽  
Sicong Zhang ◽  
...  

Botrytis cinerea is a destructive necrotrophic pathogen that can infect many plant species. The control of gray mold mainly relies on the application of fungicides, and the fungicide fludioxonil is widely used in China. However, the field fungicide resistance of B. cinerea to this compound is largely unknown. In this study, B. cinerea isolates were collected from different districts of Shanghai province in 2015–2017, and their sensitivity to fludioxonil was determined. A total of 65 out of 187 field isolates (34.76%) were found to be resistant to fludioxonil, with 36 (19.25%) showing high resistance and 29 (15.51%) showing moderate resistance. Most of these resistant isolates also showed resistance to iprodione, and some developed resistance to fungicides of other modes of action. AtrB gene expression, an indicator of MDR1 and MDR1h phenotypes, was not dramatically increased in the tested resistant isolates. Biological characteristics and osmotic sensitivity investigations showed that the fitness of resistant isolates was lower than that of sensitive ones. To investigate the molecular resistance mechanisms of B. cinerea to fludioxonil, the Bos1 amino acid sequences were compared between resistant and sensitive isolates. Resistant isolates revealed either no amino acid variations or the mutations I365S, I365N, Q369P/N373S, and N373S.


Plant Disease ◽  
1999 ◽  
Vol 83 (6) ◽  
pp. 589-589
Author(s):  
P. M. Prichard ◽  
M. K. Hausbeck ◽  
R. D. Heins

Plant height can be regulated by manipulation of day (DT) and night temperatures (NT). Traditionally, commercial flower crops are grown with a DT higher than the NT, which results in greater internode length than when the regimen is reversed. Because temperature manipulation is a popular height-control tool among growers, the influence of DT/NT regimens of 16/16, 19/19, 22/22, 16/19, 19/22, 16/22, 19/16, 22/19, and 22/16°C on foliage susceptibility to Botrytis cinerea was investigated. After a minimum 3-week temperature treatment, seed geraniums (Pelargonium × hortorum), petunias (Petunia × hybrida), and impatiens (Impatiens wallerana) were inoculated with 2.7 × 105 B. cinerea conidia per ml of water and incubated at 20°C for the duration of the experiment. When averaged over two experiments, the maximum proportion of geranium, petunia, and impatiens foliage infected was 81.5, 35.5, and 27.0%, respectively. The maximum proportion of leaves supporting sporulating B. cinerea was 59.5% for geraniums, 25.5% for petunias, and 5.5% for impatiens. Area under the disease progress curve data indicated that susceptibility of bedding plant foliage was not influenced by the difference in DT/NT regimens. Results suggest that growers that use higher NT than DT to limit plant height do not increase host susceptibility to B. cinerea. However, more rigorous disease management strategies are needed for production of seed geraniums than for petunias or impatiens.


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