scholarly journals Fitness and Competitive Ability of Botrytis cinerea Field Isolates with Dual Resistance to SDHI and QoI Fungicides, Associated with Several sdhB and the cytb G143A Mutations

2014 ◽  
Vol 104 (4) ◽  
pp. 347-356 ◽  
Author(s):  
T. Veloukas ◽  
P. Kalogeropoulou ◽  
A. N. Markoglou ◽  
G. S. Karaoglanidis
Keyword(s):  
Botrytis Cinerea ◽  
Selection Pressure ◽  
Competitive Ability ◽  
Storage Conditions ◽  
Gray Mold ◽  
Apple Fruit ◽  
Competition Experiment ◽  
Individual Fitness

Respiration inhibitors such as the succinate dehydrogenase inhibitors (SDHIs) and the quinone outside inhibitors (QoIs) are fungicide classes with increasing relevance in gray mold control. However, recent studies have shown that dual resistance to both fungicide classes is a common trait in Botrytis cinerea populations from several hosts throughout the world. Resistance of B. cinerea to SDHIs is associated with several mutations in the sdhB, sdhC, and sdhD genes, while resistance to QoIs, in most cases, is associated with the G143A mutation in the cytb gene. The objective of the current study was to investigate the fitness and the competitive ability of B. cinerea field strains possessing one of the H272Y/R/L, N230I, or P225F sdhB substitutions and the G143A mutation of cytb. Fitness parameters measured were (i) mycelial growth and conidia germination in vitro, (ii) aggressiveness and sporulation capacity in vivo, (iii) sclerotia production in vitro and sclerotia viability under different storage conditions, and (iv) sensitivity to oxidative stress imposed by diquat treatments. The competitive ability of the resistant isolates was measured in the absence and presence of the SDHI fungicides boscalid and fluopyram selection pressure. The measurements of individual fitness components showed that the H272R/G143A isolates had the lower differences compared with the sensitive isolates. In contrast, the groups of H272Y/L/G143A, N230I/G143A, and P225F/G143A isolates showed reduced fitness values compared with the sensitive isolates. Isolates possessing only the cytb G143A substitution did not show any fitness cost. The competition experiments showed that, in the absence of fungicide selection pressure, after four disease cycles on apple fruit, the sensitive isolates dominated in the population in all the mixtures tested. In contrast, when the competition experiment was conducted under the selection pressure of boscalid, a gradual decrease in the frequency of sensitive isolates was observed, whereas the frequency of H272L and P225F isolates was increased. When the competition experiment was conducted in the presence of fluopyram, the sensitive isolates were eliminated even after the first disease cycle and the P225F mutants dominated in the population. Such results suggest that the sdhB mutations may have adverse effects on the mutants. The observed dominance of sensitive isolates in the competition experiments conducted in the absence of fungicides suggest that the application of SDHIs in alternation schemes may delay the selection or reduce the frequency of SDHI-resistant mutants.

scholarly journals Characterization of Postharvest Fungicide-Resistant Botrytis cinerea Isolates From Commercially Stored Apple Fruit

2017 ◽  
Vol 107 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Wayne M. Jurick ◽  
Otilia Macarisin ◽  
Verneta L. Gaskins ◽  
Eunhee Park ◽  
Jiujiang Yu ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Gray Mold ◽  
Apple Fruit ◽  
Sublethal Dose ◽  
Long Term Storage ◽  
Pose Control ◽  
First Time

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.

scholarly journals Effects of Origanum vulgare essential oil and its two main components, carvacrol and thymol, on the plant pathogen Botrytis cinerea

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9626
Author(s):  
Huiyu Hou ◽  
Xueying Zhang ◽  
Te Zhao ◽  
Lin Zhou
Keyword(s):  
Antifungal Activity ◽  
Essential Oil ◽  
Botrytis Cinerea ◽  
Spore Germination ◽  
Gray Mold ◽  
Origanum Vulgare ◽  
Mycelium Growth ◽  
Main Components

Background Botrytis cinerea causes serious gray mold disease in many plants. This pathogen has developed resistance to many fungicides. Thus, it has become necessary to look for new safe yet effective compounds against B. cinerea. Methods Essential oils (EOs) from 17 plant species were assayed against B. cinerea, of which Origanum vulgare essential oil (OVEO) showed strong antifungal activity, and accordingly its main components were detected by GC/MS. Further study was conducted on the effects of OVEO, carvacrol and thymol in vitro on mycelium growth and spore germination, mycelium morphology, leakages of cytoplasmic contents, mitochondrial injury and accumulation of reactive oxygen species (ROS) of B. cinerea. The control efficacies of OVEO, carvacrol and thymol on tomato gray mold were evaluated in vivo. Results Of all the 17 plant EOs tested, Cinnamomum cassia, Litsea cubeba var. formosana and O. vulgare EOs had the best inhibitory effect on B. cinerea, with 0.5 mg/mL completely inhibiting the mycelium growth of B. cinerea. Twenty-one different compounds of OVEO were identified by gas chromatography–mass spectrometry, and the main chemical components were carvacrol (89.98%), β-caryophyllene (3.34%), thymol (2.39%), α-humulene (1.38%) and 1-methyl-2-propan-2-ylbenzene isopropyl benzene (1.36%). In vitro experiment showed EC50 values of OVEO, carvacrol and thymol were 140.04, 9.09 and 21.32 μg/mL, respectively. Carvacrol and thymol completely inhibited the spore germination of B. cinerea at the concentration of 300 μg/mL while the inhibition rate of OVEO was 80.03%. EC50 of carvacrol and thymol have significantly (P < 0.05) reduced the fresh and dry weight of mycelia. The collapse and damage on B. cinerea mycelia treated with 40 μg/mL of carvacrol and thymol was examined by scanning electron microscope (SEM). Through extracellular conductivity test and fluorescence microscope observation, it was found that carvacrol and thymol led to increase the permeability of target cells, the destruction of mitochondrial membrane and ROS accumulation. In vivo conditions, 1000 μg/mL carvacrol had the best protective and therapeutic effects on tomato gray mold (77.98% and 28.04%, respectively), and the protective effect was significantly higher than that of 400 μg/mL pyrimethanil (43.15%). While the therapeutic and protective effects of 1,000 μg/mL OVEO and thymol were comparable to chemical control. Conclusions OVEO showed moderate antifungal activity, whereas its main components carvacrol and thymol have great application potential as natural fungicides or lead compounds for commercial fungicides in preventing and controlling plant diseases caused by B. cinerea.

scholarly journals Actinomycete as biocontrol agents against tomato gray mold disease caused by Botrytis cinerea

2021 ◽  
Vol 48 (3) ◽  
Author(s):  
Hind Lahmyed ◽  
◽  
Rachid Bouharroud ◽  
Redouan Qessaoui ◽  
Abdelhadi Ajerrar ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Extracellular Enzymes ◽  
Chitinase Activity ◽  
Gray Mold ◽  
Antagonistic Activity ◽  
Future Research ◽  
In Planta ◽  
Tomato Fruits

The present work aims to isolate actinomycete bacteria with antagonistic abilities towards Botrytis cinerea, the causal agent of gray mold, from a soil sample collected from the rhizosphere of a healthy tomato grove. In vitro confrontation led to the isolation of 104 actinomycete isolates; fifteen isolates have shown the most significant mortality rate of the mycelial growth of B. cinerea (>50%). Based on the results of this screening, representative strains were selected to verify their in vivo antagonistic activity on tomato fruits; the reduction of B. cinerea has a percentage ranging from 52.38% to 96.19%. Furthermore, the actinomycete isolates were evaluated for their plant growth-promoting (PGP) properties and their ability to produce biocontrol-related extracellular enzymes viz., amylase, protease, cellulase, chitinase, esterases, and lecithinase. Indeed, Ac70 showed high β-1,3-glucanase activity and siderophore production (17U/ml and 43% respectively), and the highest chitinase activity (39μmol/ml) was observed for Ac24. These results indicated that these actinomycetes might potentially control gray mold caused by B. cinerea on tomato fruits. Investigations on enhancing the efficacy and survival of the biocontrol agent in planta and finding out the best formulation are recommended for future research.

scholarly journals Fitness and Competitive Ability of Botrytis cinerea Isolates with Resistance to Multiple Chemical Classes of Fungicides

2016 ◽  
Vol 106 (9) ◽  
pp. 997-1005 ◽  
Author(s):  
S. N. Chen ◽  
C. X. Luo ◽  
M. J. Hu ◽  
G. Schnabel
Keyword(s):  
Botrytis Cinerea ◽  
Competitive Ability ◽  
Selective Pressure ◽  
Spore Production ◽  
Inoculum Potential ◽  
Eastern United States ◽  
Competitive Disadvantage ◽  
Multiple Chemical

Resistance to multiple chemical classes of fungicides in Botrytis cinerea isolates from eastern United States strawberry fields is common and strategies to control them are needed. In this study, we compared fitness and competitive ability of eight sensitive isolates (S), eight isolates resistant to five or six chemical classes of fungicides but not to phenylpyrroles (5CCR), and eight isolates resistant to six or seven chemical classes including phenylpyrroles (6CCR/MDR1h). The latter included the MDR1h phenotype due to overexpression of atrB based on Δ497V/L in mrr1. The 6CCR/MDR1h isolates grew more slowly at 4°C on potato dextrose agar, and both 5CCR and 6CCR/MDR1h isolates were hypersensitive to osmotic stress compared with S isolates. In contrast, no differences were found in oxidative sensitivity, aggressiveness, and spore production in vivo, and sclerotia production and viability in vitro. In competition experiments, the 5CCR and 6CCR/MDR1h isolates were both outcompeted by S isolates and 6CCR/MDR1h isolates were outcompeted by 5CCR isolates in the absence of fungicide pressure. Under selective pressure of a fludioxonil/pyraclostrobin rotation, the 6CCR/MDR1h isolates dominated after coinoculation with 5CCR and S isolates. The competitive disadvantage of 5CCR and especially 6CCR/MDR1h isolates suggest that, in the absence of fungicide selection pressure, S isolates may reduce inoculum potential of multifungicide-resistant isolates under field conditions.

scholarly journals First Report of Fenpyrazamine Resistance in Botrytis cinerea from Strawberry Fields in Spain

2018 ◽  
Vol 19 (1) ◽  
pp. 45-45
Author(s):  
Dolores Fernández-Ortuño ◽  
Alejandra Vielba-Fernández ◽  
Alejandro Pérez-García ◽  
Juan A. Torés ◽  
Antonio de Vicente
Keyword(s):  
Botrytis Cinerea ◽  
Gray Mold ◽  
In Vivo Studies ◽  
Cross Resistance ◽  
In Vitro Tests ◽  
Class Iii ◽  
Single Spore ◽  
First Report

Botrytis cinerea Pers. is an important fungal pathogen responsible for gray mold, one of the most economically important diseases of strawberry (Fragaria × ananassa) worldwide. The primary disease management strategy involves the application of different classes of fungicides, including the sterol biosynthesis inhibitor class III fungicide fenpyrazamine. In 2014 and 2015, strawberries affected with gray mold symptoms were collected from eight locations in Huelva, where fenhexamid had been used extensively. Twenty-five B. cinerea single-spore isolates were examined to determine EC50 values and to determine a discriminatory dose to monitor fenpyrazamine resistance in the field in future studies. The in vitro tests divided the isolates into two groups: 15 sensitive (EC50 from 0.02 to 1.3 μg/ml) and 10 resistant (EC50 from 50.1 to 172.6 μg/ml), which showed cross-resistance with fenhexamid. Performance of fenpyrazamine in in vivo studies was also carried out. Only the fenpyrazamine-resistant isolates developed gray mold on the fungicide-treated fruit. This is the first report of fenpyrazamine resistance in B. cinerea from strawberry fields in Spain and cross-resistance with fenhexamid.

scholarly journals Resistance to Pyraclostrobin and Boscalid in Populations of Botrytis cinerea from Stored Apples in Washington State

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 604-612 ◽  
Author(s):  
Y. K. Kim ◽  
C. L. Xiao
Keyword(s):  
Botrytis Cinerea ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Gray Mold ◽  
Apple Fruit ◽  
Conidial Germination ◽  
Postharvest Disease ◽  
Cross Resistance ◽  
Baseline Sensitivity

Gray mold caused by Botrytis cinerea is a major postharvest disease of apple. Pristine, a formulated mixture of pyraclostrobin and boscalid, was recently registered for use on apple. Pristine applied within 2 weeks before harvest is effective in controlling gray mold in stored apple fruit. To determine the baseline sensitivity of B. cinerea populations to these fungicides, 40 isolates from organic and 80 from conventional apple orchards where Pristine had not been used were tested for mycelial growth or conidial germination on fungicide-amended media. To monitor fungicide resistance, gray-mold-decayed apple fruit originating from orchards in which Pristine had been used were sampled from a fruit packinghouse. Isolates of B. cinerea recovered from the fruit were tested for resistance to the two fungicides. In the in vivo study in the orchards, Pristine was applied to fruit 1 day before harvest. Fruit were then harvested, wounded, and inoculated with isolates exhibiting different fungicide-resistance phenotypes. Fruit were stored at 0°C for 8 weeks for decay development. The effective concentration that inhibits mycelial growth by 50% relative to the control (EC50) values for sensitive isolates ranged from 0.008 to 0.132 μg/ml (mean = 0.043, n = 116) for pyraclostrobin and from 0.003 to 0.183 μg/ml (mean = 0.075, n = 117) for Pristine in a mycelial growth assay on potato dextrose agar. The EC50 values of boscalid for sensitive isolates ranged from 0.065 to 1.538 μg/ml (mean = 0.631, n = 29) in a conidial germination assay on water agar. Four isolates were resistant to pyraclostrobin, with resistance factors (RFs) ranging from 12 to 4,193. Of the four pyraclostrobin-resistant isolates, one also was resistant to boscalid (RF = 14) and Pristine (RF = 373), and two exhibited reduced sensitivity to Pristine (RF = 16 and 17). The minimum inhibitory concentration for conidial germination (for boscalid) or mycelial growth (for pyraclostrobin and Pristine) of sensitive isolates was 5 μg/ml, which is thus recommended as a discriminatory concentration for phenotyping isolates for resistance to these fungicides. Of the 56 isolates obtained from decayed apple fruit that had been exposed to Pristine, 11 (approximately 20%) were resistant to both pyraclostrobin and boscalid and 1 was resistant only to pyraclostrobin. Of the additional 43 isolates obtained from decayed apple fruit originating from an organic orchard, 3 were resistant only to pyraclostrobin, 2 were resistant only to boscalid, and 2 were resistant to both fungicides. It appeared that there was no cross resistance between pyraclostrobin and boscalid because of the existence of isolates resistant only to either pyraclostrobin or boscalid. Pristine applied at label rate in the orchard failed to control gray mold on apple fruit inoculated with the Pristine-resistant isolates. This is the first report of multiple resistance to pyraclostrobin, boscalid, and Pristine in field populations of B. cinerea. Our results suggest that the development of dual resistance to pyraclostrobin and boscalid in B. cinerea populations could result in the failure to control gray mold with Pristine.

scholarly journals Dark Period Following UV-C Treatment Enhances Killing of Botrytis cinerea Conidia and Controls Gray Mold of Strawberries

2016 ◽  
Vol 106 (4) ◽  
pp. 386-394 ◽  
Author(s):  
Wojciech J. Janisiewicz ◽  
Fumiomi Takeda ◽  
D. Michael Glenn ◽  
Mary J. Camp ◽  
Wayne M. Jurick
Keyword(s):  
Botrytis Cinerea ◽  
Fruits And Vegetables ◽  
Dark Period ◽  
Gray Mold ◽  
Apple Fruit ◽  
Tube Growth ◽  
Before And After ◽  
Negative Effect ◽  
Uv C

Strawberries are available throughout the year either from production in the field or from high and low tunnel culture. Diversity of production conditions results in new challenges in controlling diseases before and after harvest. Fungicides have traditionally been used to control these diseases; however, their limitations necessitate a search for new approaches. We found that UV-C irradiation of Botrytis cinerea, a major pathogen of strawberry, can effectively kill this fungus if a dark period follows the treatment. The inclusion of a 4-h dark period resulted in almost complete kill of B. cinerea conidia on agar media at a dose of 12.36 J/m2. The UV-C dose did not cause a reduction in photosynthesis in strawberry leaves or discoloration of sepals, even after exposing plants repeatedly (twice a week) for 7 weeks. Although irradiation of dry conidia of B. cinerea with this dose resulted in some survival, the conidia were not infective and not able to cause decay even when inoculated onto a highly susceptible mature apple fruit. Irradiation of strawberry pollen at 12.36 J/m2 did not affect pollen germination, tube growth and length in vitro, or germination and tube growth in the style of hand-pollinated emasculated strawberry flowers. No negative effect of the UV-C treatment was observed on fruit yield and quality in high tunnel culture. In the fruit and flower petal inoculation tests, the UV-C treatment was highly effective in reducing fruit decay and petal infection. This UV-C treatment with an exposure time of 60 s may be useful in controlling gray mold in tunnel production of strawberries and may also have the potential for use in intensive field and indoor production of other fruits and vegetables providing that a 4-h dark period follows the irradiation.

scholarly journals Stability and Fitness of Pyraclostrobin- and Boscalid-Resistant Phenotypes in Field Isolates of Botrytis cinerea from Apple

2011 ◽  
Vol 101 (11) ◽  
pp. 1385-1391 ◽  
Author(s):  
Y. K. Kim ◽  
C. L. Xiao
Keyword(s):  
Botrytis Cinerea ◽  
Apple Fruit ◽  
Fitness Components ◽  
Mean Values ◽  
Individual Fitness ◽  
Competitive Disadvantage ◽  
Stability Of Resistance ◽  
Sensitive Isolate ◽  
Initial Generation

Phenotype stability, fitness, and competitive ability of pyraclostrobin- and boscalid-resistant isolates of Botrytis cinerea from apple were investigated. Stability of resistance was determined after consecutive transfers on potato dextrose agar (PDA) or being cycled on apple fruit. In vitro fitness components mycelial growth, osmotic sensitivity, conidial germination, and sporulation were evaluated on agar media. Pathogenicity, virulence and sporulation on apple fruit were evaluated at both 20 and 0°C. Competition between fungicide-resistant and -sensitive isolates on apple fruit also was evaluated. Resistance to the two fungicides was retained at levels similar to that of the initial generation after 20 and 10 transfers on PDA and five and three disease cycles on apple fruit at 20 and 0°C, respectively. Great variability in individual fitness components tested was observed among isolates within the same phenotype groups either sensitive or resistant to the fungicides but, when compared as phenotype groups, there were no significant differences in the mean values of these fitness components between resistant and sensitive phenotypes except that the phenotype resistant only to boscalid produced fewer conidia in vitro than sensitive isolates. Resistant isolates were as pathogenic and virulent on apple fruit as sensitive isolates. There was no significant correlation between the values of individual fitness components tested and the level of resistance to pyraclostrobin or boscalid, except that virulence at 20°C positively correlated with the level of resistance to the two fungicides. The final frequency of pyraclostrobin-resistant individuals in the populations was significantly decreased compared with the initial generation and no boscalid-resistant individuals were detected after four disease cycles on apple fruit inoculated with a pair mixture of a dual-sensitive isolate and one isolate each of the three phenotypes resistant to pyraclostrobin, boscalid, or both. The results suggest that resistance of B. cinerea to pyraclostrobin and boscalid was stable in the absence of the fungicides and that resistance to the two fungicides did not significantly impair individual fitness components tested. However, both pyraclostrobin- and boscalid-resistant isolates exhibited competitive disadvantage over the dual-sensitive isolate on apple fruit.

scholarly journals Potencial de extratos etanólicos de propólis e extratos aquosos de plantas espontâneas no controle de doenças pós-colheita do morango

2016 ◽  
Vol 11 (1) ◽  
pp. 57
Author(s):  
Gabriela Silva Moura ◽  
Jonas Marcelo Jaski ◽  
Gilmar Franzener
Keyword(s):  
Antifungal Activity ◽  
Botrytis Cinerea ◽  
Gray Mold ◽  
Alternative Methods ◽  
Wild Plants ◽  
Rhizopus Nigricans ◽  
Post Harvest ◽  
Control Water

<p>A cultura do morangueiro é severamente acometida por várias doenças, dentre elas o mofo cinzento, causado por <em>Botrytis cinerea</em> é considerada a doença mais severa na pós-colheita. Visando reduzir o uso de fungicidas sintéticos, vem sendo realizadas pesquisas propondo a utilização de métodos alternativos de controle de patógenos pós-colheita envolvendo a utilização de extratos vegetais, uso de biofungicidas e óleos essenciais. Assim, o presente trabalho teve como objetivo avaliar o potencial de diferentes extratos de própolis e plantas espontâneas no controle de podridão pós-colheita causada pelo fungo <em>B. cinerea</em> em morangos. Para avaliar a atividade antifúngica direta dos extratos etanólico de própolis e extratos aquosos de plantas espontâneas sobre <em>B. cinerea,</em> foi realizado o experimento <em>in vitro</em>, utilizando-se os tratamentos própolis verde 0,5%; própolis verde 2,5%; própolis marrom 0,5%; própolis marrom 2,5%; língua-de-vaca 10%; assa-peixe 10%; rubim 10%; tansagem 10%; testemunha (água). As medições do diâmetro das colônias foram iniciadas 48, 72 e 96 horas após a instalação do experimento. No experimento <em>in vivo </em>os frutos foram imersos nos tratamentos descritos acima. Após cinco dias avaliou-se a incidência e severidade da doença mofo cinzento e das doenças pós-colheita como antracnose e podridão de Rhizopus que apareceram no experimento. Utilizou-se o delineamento experimental inteiramente casualizado (DIC) com quatro e cinco repetições para o ensaio <em>in vitro</em> e <em>in vivo,</em> respectivamente<em>.</em> Os resultados mostram que os extratos etanólicos de própolis verde e marrom a 2,5% apresentaram <em>in vitro</em> e <em>in vivo </em>atividade antifúngica a <em>B. cinerea</em> e <em>Rhizopus nigricans,</em> respectivamente.</p><p align="center"><strong><em>Potential of propolis extracts and extracts etanol spontaneous plants aqueous in control of diseases of strawberry post-harvest</em></strong><strong><em></em></strong></p><p><strong>Abstract</strong><strong>: </strong>The strawberry crop is severely affected by various diseases, including gray mold, caused by <em>Botrytis cinerea</em> is considered the most severe disease in post-harvest fruit. To reduce the use of synthetic fungicides, has been carried out research proposing the use of alternative methods of control postharvest pathogens involving the use of plant extracts, use of biofungicides, essential oils among others. Thus, this study aimed to evaluate the potential of different propolis extracts and wild plants in the control of post-harvest rot caused by the fungus <em>Botrytis cinerea</em> in strawberries. To evaluate the direct antifungal activity of ethanolic extracts of propolis and aqueous extracts of wild plants of B. cinerea, the in vitro experiment was performed, using treatments propolis 0.5%; propolis 2.5%; brown propolis 0.5%; brown propolis 2.5%; control (water + alcohol 2%); cow tongue 10%; assa-fish 10%; rubim 10%; tansagem 10%; control (water). Measurements of the diameter of the colonies were started 48, 72 and 96 hours after installation of the experiment. Conducted the in vivo experiment in which the fruits of strawberry plants were immersed in the treatments described above. After five days we evaluated the incidence and severity of gray mold disease and post-harvest diseases such as anthracnose and Rhizopus rot appearing in the experiment. We used a completely randomized design (CRD) with four and five replicates for the in vitro assay and in vivo, respectively. The results show that ethanol extracts of green and brown propolis 2.5% presented in vitro and in vivo antifungal activity to <em>B. cinerea</em> and <em>Rhizopus nigricans</em> respectively.</p>

scholarly journals Ultra-Structural Alterations in Botrytis cinerea—The Causal Agent of Gray Mold—Treated with Salt Solutions

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 582 ◽  
Author(s):  
Khamis Youssef ◽  
Sergio Ruffo Roberto ◽  
Admilton G. de Oliveira
Keyword(s):  
Electron Microscopy ◽  
Botrytis Cinerea ◽  
Morphological Changes ◽  
Pathogenic Fungi ◽  
Gray Mold ◽  
In Vitro Tests ◽  
Salt Solutions ◽  
Grape Berries

Potassium bicarbonate (PB), calcium chelate (CCh), and sodium silicate (SSi) have been extensively used as antifungal generally recognized as safe (GRAS) compounds against plant pathogenic fungi. In this research, in in vitro tests, the radial growth, conidial germination, and germ tube elongation of Botrytis cinerea was completely inhibited at 0.3% of PB, SSi, and CCh. In in vivo tests, application of PB, SSi, and CCh completely inhibited the occurrence of gray mold incidence of inoculated ‘Italia’ grape berries at concentrations of 1.0, 0.8, and 0.8%, respectively. In order to investigate the detailed mechanisms by which salts exhibited antifungal activity, we analyzed their influence on morphological changes by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and also on reactive species of oxygen (ROS), mitochondrial membrane potential (MMP), and adenosine triphosphate (ATP) content. Defects such as malformation and excessive septation were detected on salt-treated hyphae morphology observed by SEM. The internal structure of conidia treated or not with salt solutions was examined by TEM. In treated conidia, most of the conidia were affected and cellular vacuolization and cytoplasmic disorganization was observed. For ROS accumulation, a higher increase was observed in fluorescent conidia in presence of PB, SSi, and CCh by 75, 68, and 70% as compared to control, respectively. MMP was significantly decreased after salt application indicating a loss of mitochondria function. Also, luminescence showed that B. cinerea-conidia treated with salts contained less ATP than the untreated conidia. The results obtained herein are a step towards a comprehensive understanding of the mode of action by which salts act as antifungal agents against B. cinerea.

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