Biological control of apple blue mold withPseudomonas fluorescens

2005 ◽  
Vol 51 (7) ◽  
pp. 591-598 ◽  
Author(s):  
Hassan-Reza Etebarian ◽  
Peter L Sholberg ◽  
Kenneth C Eastwell ◽  
Ronald J Sayler
Keyword(s):  
Biological Control ◽  
Fluorescent Protein ◽  
Biological Control Agent ◽  
Major Effect ◽  
Penicillium Expansum ◽  
Postharvest Disease ◽  
Dual Culture ◽  
Blue Mold ◽  
Iron Chelate ◽  
Penicillium Spp

Pseudomonas fluorescens isolate 1100-6 was evaluated as a potential biological control agent for apple blue mold caused by Penicillium expansum or Penicillium solitum. Both the wild-type isolate 1100-6 and a genetically modified derivative labeled with the gene encoding the green fluorescent protein (GFP) were compared. The P. fluorescens isolates with or without GFP equally reduced the growth of Penicillium spp. and produced large zones of inhibition in dual culture plate assays. Cell-free metabolites produced by the bacterial antagonists reduced the colony area of Penicillium isolates by 17.3% to 78.5%. The effect of iron chelate on the antagonistic potential of P. fluorescens was also studied. The use of iron chelate did not have a major effect on the antagonistic activity of P. fluorescens. With or without GFP, P. fluorescens significantly reduced the severity and incidence of apple decay by 2 P. expansum isolates after 11 d at 20 °C and by P. expansum and P. solitum after 25 d at 5 °C when the biocontrol agents were applied in wounds 24 or 48 h before challenging with Penicillium spp. Populations of P. fluorescens labeled with the GFP were determined 1, 9, 14, and 20 d after inoculation at 5 °C. The log CFU/mL per wound increased from 6.95 at the time of inoculation to 9.12 CFU/mL (P < 0.05) 25 d after inoculation at 5 °C. The GFP strain did not appear to penetrate deeply into wounds based on digital photographs taken with an inverted fluorescence microscope. These results indicate that P. fluorescens isolate 1100-6 could be an important new biological control for apple blue mold.Key words: Penicillium expansum, P. solitum, postharvest disease, Malus, GFP.

scholarly journals Characterization of Penicillium Isolates Associated with Blue Mold on Apple in Uruguay

Plant Disease ◽  
2004 ◽  
Vol 88 (1) ◽  
pp. 23-28 ◽  
Author(s):  
M. J. Pianzzola ◽  
M. Moscatelli ◽  
S. Vero
Keyword(s):  
Fragment Length Polymorphism ◽  
Random Amplified Polymorphic Dna ◽  
Species Level ◽  
Penicillium Expansum ◽  
Postharvest Disease ◽  
Pear Fruit ◽  
Blue Mold ◽  
Penicillium Spp ◽  
Its1 And Its2

Blue mold caused by Penicillium spp. is the most important postharvest disease of apple in Uruguay. Fourteen isolates of Penicillium were recovered from rotten apple and pear fruit with blue mold symptoms, and from water from flotation tanks in commercial apple juice facilities. Phenotypic identification to species level was performed, and the isolates were tested for sensitivity to commonly used postharvest fungicides. Genetic characterization of the isolates was performed with restriction fragment length polymorphism of the region including the internal transcribed spacer (ITS) ITS1 and ITS2 and the 5.8SrRNA gene (ITS1-5.8SrRNA gene-ITS2) ribosomal DNA region and with random amplified polymorphic DNA (RAPD) primers. Both techniques were able to differentiate these isolates at the species level. RAPD analysis proved to be an objective, rapid, and reliable tool to identify Penicillium spp. involved in blue mold of apple. In all, 11 isolates were identified as Penicillium expansum and 3 as P. solitum. This is the first report of P. solitum as an apple pathogen in Uruguay.

scholarly journals Identification of the Fungal Pathogens of Postharvest Disease on Peach Fruits and the Control Mechanisms of Bacillus subtilis JK-14

Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 322 ◽  
Author(s):  
Shuwu Zhang ◽  
Qi Zheng ◽  
Bingliang Xu ◽  
Jia Liu
Keyword(s):  
Biological Control ◽  
Bacillus Subtilis ◽  
Fungal Pathogens ◽  
Biological Control Agent ◽  
Storage Period ◽  
Control Agent ◽  
Antagonistic Activity ◽  
Postharvest Disease ◽  
Economic Losses ◽  
Control Mechanisms

Postharvest fungal disease is one of the significant factors that limits the storage period and marketing life of peaches, and even result in serious economic losses worldwide. Biological control using microbial antagonists has been explored as an alternative approach for the management of postharvest disease of fruits. However, there is little information available regarding to the identification the fungal pathogen species that cause the postharvest peach diseases and the potential and mechanisms of using the Bacillus subtilis JK-14 to control postharvest peach diseases. In the present study, a total of six fungal isolates were isolated from peach fruits, and the isolates of Alternaria tenuis and Botrytis cinerea exhibited the highest pathogenicity and virulence on the host of mature peaches. In the culture plates, the strain of B. subtilis JK-14 showed the significant antagonistic activity against the growth of A. tenuis and B. cinerea with the inhibitory rates of 81.32% and 83.45% at 5 days after incubation, respectively. Peach fruits treated with different formulations of B. subtilis JK-14 significantly reduced the mean disease incidences and lesion diameters of A. tenuis and B. cinerea. The greatest mean percent reduction of the disease incidences (81.99% and 71.34%) and lesion diameters (82.80% and 73.57%) of A. tenuis and B. cinerea were obtained at the concentration of 1 × 107 CFU mL−1 (colony forming unit, CFU). Treatment with the strain of B. subtilis JK-14 effectively enhanced the activity of the antioxidant enzymes-superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in A. tenuis and B. cinerea inoculated peach fruits. As such, the average activities of SOD, POD and CAT were increased by 36.56%, 17.63% and 20.35%, respectively, compared to the sterile water treatment. Our results indicate that the isolates of A. tenuis and B. cinerea are the main pathogens that cause the postharvest peach diseases, and the strain of B. subtilis JK-14 can be considered as an environmentally-safe biological control agent for the management of postharvest fruits diseases. We propose the possible mechanisms of the strain of B. subtilis JK-14 in controlling of postharvest peach diseases.

scholarly journals Prevalence and Incidence of Phacidiopycnis Rot in d'Anjou Pears in Washington State

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 413-418 ◽  
Author(s):  
C. L. Xiao ◽  
R. J. Boal
Keyword(s):  
The United States ◽  
Gray Mold ◽  
Washington State ◽  
Postharvest Disease ◽  
Wound Infections ◽  
Postharvest Diseases ◽  
Pear Fruit ◽  
Blue Mold ◽  
Penicillium Spp ◽  
Organic Orchards

Phacidiopycnis rot, caused by Phacidiopycnis piri, is a newly recognized postharvest disease in pear fruit (Pyrus communis cv. d'Anjou) in the United States. To determine the prevalence and incidence of this disease, decayed fruit were sampled during packing and repacking operations from four packinghouses in 2001 and 2002. During March to May (repacking) in 2001, Phacidiopycnis rot was found in packed fruit that were stored in cardboard boxes from 22 of 26 grower lots (orchards), and accounted for 5 to 71% of the total decay. Phacidiopycnis rot, gray mold caused by Botrytis cinerea, and blue mold caused by Penicillium spp. accounted for an average of 34.1, 10.3, and 33.6% of decayed fruit from conventional orchards, respectively; and 22.8, 35.7, and 23.5% of decayed fruit from organic orchards, respectively. During November 2001 to January 2002 (packing), Phacidiopycnis rot was observed in fruit that were stored in field bins before packing from 30 of 33 grower lots, accounting for 18.4% of decayed fruit sampled. During March to May in 2002, Phacidiopycnis rot was responsible for 2 to 68% of decayed fruit sampled from 36 of 39 grower lots. Phacidiopycnis rot, gray mold, and blue mold accounted for an average of 19.6, 26.8, and 37.4% of decayed fruit from conventional orchards, respectively; and 42.2, 25.7, and 8.2% of decayed fruit from organic orchards, respectively. Most Phacidiopycnis rot that occurred in field bins before packing appeared to originate from wound infections; whereas after packing, approximately 60 and 30% of Phacidiopycnis rot originated from stem and calyx infections, respectively. This study indicates that Phacidiopycnis rot should be considered one of the targets for control of postharvest diseases in d'Anjou pears in the region.

Evaluation of fungal isolates for the inhibition of vegetative growth of Venturis inaequalis

1997 ◽  
Vol 75 (4) ◽  
pp. 626-631 ◽  
Author(s):  
A. Ouimet ◽  
O. Carisse ◽  
P. Neumann
Keyword(s):  
Biological Control ◽  
Vegetative Growth ◽  
Biological Control Agent ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Inhibitory Effect ◽  
Control Agent ◽  
Dual Culture ◽  
Inhibitory Effects ◽  
Aureobasidium Sp

As a part of a broader study on biological control of apple scab, caused by Venturia inaequalis, a collection of 183 microorganisms originating from apple leaf litter was evaluated for their inhibitory effects on the vegetative growth of V. inaequalis. In a first screening, based on dual culture, 31 isolates (17%) showed inhibition. From these isolates, 11 fungi were selected for quantitative evaluation based on the presence of a distinct zone of inhibition. The selected fungi were evaluated again, in a more precise test, which indicated that isolates P164A (Ophiostoma sp.), P66A (Chaetophoma sp.), P26A (Aureobasidium sp.), P59A (Phoma sp.), and P28A (unidentified) inhibited 95.3, 88.9, 85.8, 80.7, and 80.1% of mycelial growth, respectively. Inhibition by the most effective fungus (Ophiostoma sp.) lasted for more than 58 days. A test using culture filtrates, incubated over time, was carried out to determine whether the living fungus was a prerequisite for inhibition. The inhibitory effect of metabolites secreted by the selected fungi was less than 5%. This study revealed the potential of at least five fungi that could be considered in the development of a biological control agent against V. inaequalis. Key words: antifungal inhibition, apple scab, biological control.

scholarly journals Characterization of Fludioxonil-Resistant and Pyrimethanil-Resistant Phenotypes of Penicillium expansum from Apple

2008 ◽  
Vol 98 (4) ◽  
pp. 427-435 ◽  
Author(s):  
H. X. Li ◽  
C. L. Xiao
Keyword(s):  
Osmotic Stress ◽  
The United States ◽  
Apple Fruit ◽  
Penicillium Expansum ◽  
Postharvest Disease ◽  
Wild Type ◽  
Blue Mold ◽  
Pome Fruit ◽  
Development Of Resistance ◽  
Resistant Mutants

Penicillium expansum is the primary cause of blue mold, a major postharvest disease of apple. Fludioxonil and pyrimethanil are two newly registered postharvest fungicides for pome fruit in the United States. To evaluate the potential risk of resistance development in P. expansum to the new postharvest fungicides, one isolate of each of thiabendazole-resistant (TBZ-R) and -sensitive (TBZ-S) P. expansum was exposed to UV radiation to generate fungicide-resistant mutants. Four fludioxonil highly-resistant mutants (EC50 > 1,000 μg/ml) and four pyrimethanil-resistant mutants (EC50 > 10 μg/ml) were tested for sensitivities to thiabendazole, fludioxonil, and pyrimethanil, and fitness parameters including mycelial growth, sporulation on potato dextrose agar (PDA), sensitivity to osmotic stress, and pathogenicity and sporulation on apple fruit. The stability of resistance of the mutants was tested on PDA and apple fruit. Efficacy of the three fungicides to control blue mold incited by the mutants was evaluated on apple fruit. Six fungicide-resistant phenotypes were identified among the parental wild-type isolates and their mutants based upon their resistance levels. All four fludioxonil highly-resistant mutants were sensitive to pyrimethanil and retained the same phenotypes of resistance to TBZ as the parental isolates. All four pyrimethanil-resistant mutants had a low level of resistance to fludioxonil with a resistance factor >15. The two pyrimethanil-resistant mutants derived from a TBZ-S isolate became resistant to TBZ at 5 μg/ml. After 20 successive generations on PDA and four generations on apple fruit, the mutants retained the same phenotypes as the original generations. All mutants were pathogenic on apple fruit at both 0 and 20°C, but fludioxonil highly-resistant mutants were less virulent and produced fewer conidia on apple fruit than pyrimethanil-resistant mutants and their parental wild-type isolates. Compared with the parental isolates, all four fludioxonil highly-resistant mutants had an increased sensitivity to osmotic stress on PDA amended with NaCl, while the pyrimethanil-resistant mutants did not. Pyrimethanil was effective against blue mold caused by fludioxonil-resistant mutants at both 0 and 20°C. Pyrimethanil and fludioxonil reduced blue mold incited by pyrimethanil-resistant mutants during 12-week storage at 0°C but were not effective at 20°C. TBZ was not effective against pyrimethanil-resistant mutants derived from TBZ-S wild-type isolates at room temperature but provided some control at 0°C. The results indicate that: (i) a fitness cost was associated with fludioxonil highly resistant mutants of P. expansum in both saprophytic and pathogenic phases of the pathogen but not pyrimethanil-resistant mutants; (ii) pyrimethanil possessed a higher risk than fludioxonil in the development of resistance in P. expansum; and (iii) triple resistance to the three apple-postharvest fungicides could emerge and become a practical problem if resistance to pyrimethanil develops in P. expansum populations.

scholarly journals Cladobotryum mycophilum as Potential Biocontrol Agent

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 891
Author(s):  
Mila Santos ◽  
Fernando Diánez ◽  
Alejandro Moreno-Gavíra ◽  
Brenda Sánchez-Montesinos ◽  
Francisco J. Gea
Keyword(s):  
Biological Control ◽  
Fusarium Oxysporum ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Control Agent ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Dual Culture ◽  
Potential Biocontrol Agent

A study was conducted to explore the efficacy of potential biocontrol agent Cladobotryum mycophilum against different phytopathogenic fungi. The growth rates of 24 isolates of C. mycophilum were determined, and their antagonistic activity was analysed in vitro and in vivo against Botrytis cinerea, Fusarium oxysporum f. sp. radicis-lycopersici, Fusarium oxysporum f.sp. cucumerinum, Fusarium solani, Phytophthora parasitica, Phytophthora capsici, Pythium aphanidermatum and Mycosphaerella melonis. Most isolates grow rapidly, reaching the opposite end of the Petri dish within 72–96 h. Under dual-culture assays, C. mycophilum showed antagonistic activity in vitro against all phytopathogenic fungi tested, with mycelial growth inhibition ranging from 30 to 90% against all the different phytopathogens tested. Similarly, of all the selected isolates, CL60A, CL17A and CL18A significantly (p < 0.05) reduced the disease incidence and severity in the plant assays compared to the controls for the different pathosystems studied. Based on these results, we conclude that C. mycophilum can be considered as a potential biological control agent in agriculture. This is the first study of Cladobotryum mycophilum as a biological control agent for different diseases caused by highly relevant phytopathogens in horticulture.

Use of Green Fluorescent Protein and Image Analysis to Quantify Proliferation of Trichoderma harzianum in Nonsterile Soil

2004 ◽  
Vol 94 (12) ◽  
pp. 1383-1389 ◽  
Author(s):  
K. A. Orr ◽  
G. R. Knudsen
Keyword(s):  
Biological Control ◽  
Image Analysis ◽  
Green Fluorescent Protein ◽  
Trichoderma Harzianum ◽  
Fluorescent Protein ◽  
Biological Control Agent ◽  
Hyphal Growth ◽  
Epifluorescence Microscopy ◽  
Nonsterile Soil ◽  
Green Fluorescent

One drawback of traditional methods for fungal biomass measurement is the inability to distinguish biomass of an introduced fungus from that of the indigenous microbial community in nonsterile soil. We quantified biomass of a specific fungal biological control agent in nonsterile soil using epifluorescence microscopy and image analysis of green fluorescent protein (GFP)-expressing Trichoderma harzianum (ThzID1-M3). Numbers of colony forming units on a semiselective medium were compared with biomass estimates from image analysis, after ThzID1-M3 was incubated in soil that either remained moist (-0.05 MPa) for 14 to 21 days or remained moist for approximately 5 days and then was allowed to dry to <-3.0 MPa. Recovery of significant numbers of ThzID1-M3 propagules lagged approximately 3 days behind initiation of hyphal growth. Reductions in both colony counts and biomass were observed over time when soil was allowed to dry. However, in soil that remained moist, colony counts increased over a 14- to 21-day period even though biomass declined after approximately 3 to 5 days. Our results confirm that use of GFP, along with epifluorescence microscopy, is a useful tool to distinguish active hyphal biomass, the form of the fungus that is functional for biological control, from inactive propagules such as conidia or chlamydospores that are enumerated by plate counts.

scholarly journals Biological Control of Pear Valsa Canker Caused by Valsa pyri Using Penicillium citrinum

Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 198
Author(s):  
Hongbo Yuan ◽  
Bingke Shi ◽  
Tianxiang Huang ◽  
Zengqiang Zhou ◽  
Li Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Biological Control Agent ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Control Agent ◽  
Penicillium Citrinum ◽  
Lesion Length ◽  
Dual Culture ◽  
Valsa Canker

Valsa canker caused by Valsa pyri is one of the most destructive diseases of commercial pear. For the present analysis, 29 different endophytic fungal strains were isolated from the branches of a healthy pear tree. In dual culture assays, strain ZZ1 exhibited robust antifungal activity against all tested pathogens including Valsa pyri. Microscopic analyses suggested that following co-culture with ZZ1, the hyphae of V. pyri were ragged, thin, and ruptured. ZZ1 also induced significant decreases in lesion length and disease incidence on detached pear branches inoculated with V. pyri. ZZ1 isolate-derived culture filtrates also exhibited antifungal activity against V. pyri, decreasing mycelial growth and conidium germination and inhibiting V. pyri-associated lesion development on pear branches. These results suggest that the ZZ1 isolate has the potential for use as a biological control agent against V. pyri. The strain was further identified as Penicillium citrinum based on its morphological characteristics and molecular analyses. Overall, these data highlight a potentially valuable new biocontrol resource for combating pear Valsa canker.

scholarly journals First Report of Penicillium expansum Isolates Resistant to Pyrimethanil from Stored Apple Fruit in Pennsylvania

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1004-1004 ◽  
Author(s):  
H. J. Yan ◽  
V. L. Gaskins ◽  
I. Vico ◽  
Y. G. Luo ◽  
W. M. Jurick
Keyword(s):  
United States ◽  
The United States ◽  
Apple Fruit ◽  
Washington State ◽  
Penicillium Expansum ◽  
Economic Losses ◽  
Conidial Suspension ◽  
Blue Mold ◽  
First Report ◽  
Penicillium Spp

Apples in the United States are stored in low-temperature controlled atmospheres for 9 to 12 months and are highly susceptible to blue mold decay. Penicillium spp. cause significant economic losses worldwide and produce mycotoxins that contaminate processed apple products. Blue mold is managed by a combination of cultural practices and the application of fungicides. In 2004, a new postharvest fungicide, pyrimethanil (Penbotec 400 SC, Janseen PMP, Beerse, Belgium) was registered for use in the United States to control blue mold on pome fruits (1). In this study, 10 blue mold symptomatic ‘Red Delicious’ apples were collected in May 2011 from wooden bins at a commercial facility located in Pennsylvania. These fruit had been treated with Penbotec prior to controlled atmosphere storage. Ten single-spore Penicillium spp. isolates were analyzed for growth using 96-well microtiter plates containing Richards minimal medium amended with a range of technical grade pyrimethanil from 0 to 500 μg/ml. Conidial suspensions adjusted to 1 × 105 conidia/ml were added to three 96-well plates for each experiment; all experiments were repeated three times. Nine resistant isolates had prolific mycelial growth at 500 μg/ml, which is 1,000 times the discriminatory dose that inhibited baseline sensitive P. expansum isolates from Washington State (1). However, one isolate (R13) had limited conidial germination and no mycelial proliferation at 0.5 μg/ml and was categorized as sensitive. One resistant (R22) and one sensitive (R13) isolate were selected on the basis of their different sensitivities to pyrimethanil. Both isolates were identified as P. expansum via conventional PCR using β-tubulin gene-specific primers according to Sholberg et al. (2). Analysis of the 2X consensus amplicon sequences from R13 and R22 matched perfectly (100% identity and 0.0 E value) with other P. expansum accessions in GenBank including JN872743.1, which was isolated from decayed apple fruit from Washington State. To determine if pyrimethanil applied at the labeled rate of 500 μg/ml would control R13 or R22 in vivo, organic ‘Gala’ apple fruit were wounded, inoculated with 50 μl of a conidial suspension (1 × 104 conidia/ml) of either isolate, dipped in Penbotec fungicide or sterile water, and stored at 25°C for 7 days. Twenty fruit composed a replicate within a treatment and the experiment was performed twice. Non-inoculated water-only controls were symptomless, while water-dipped inoculated fruit had 100% decay with mean lesion diameters of 36.8 ± 2.68 mm for R22 and 38.5 ± 2.61 mm for R13. The R22 isolate caused 30% decay with 21.6 ± 5.44 mm lesions when inoculated onto Penbotec-treated apples, while the R13 isolate had 7.5% decay incidence with mean lesion diameters of 23.1 ± 3.41 mm. The results from this study demonstrate that P. expansum pyrimethanil-resistant strains are virulent on Penbotec-treated apple fruit and have the potential to manifest in decay during storage. To the best of our knowledge, this is the first report of pyrimethanil resistance in P. expansum from Pennsylvania, a major apple growing region for the United States. Moreover, these results illuminate the need to develop additional chemical, cultural, and biological methods to control this fungus. References: (1) H. X. Li and C. L. Xiao. Phytopathology 98:427, 2008. (2) P. L. Sholberg et al. Postharvest Biol. Technol. 36:41, 2005.

Influence of nutrients on growth ofEpicoccum nigrum

1996 ◽  
Vol 42 (7) ◽  
pp. 647-654 ◽  
Author(s):  
Ting Zhou ◽  
R. D. Reeleder ◽  
S. A. Sparace
Keyword(s):  
Amino Acids ◽  
Biological Control ◽  
Glutamic Acid ◽  
Biological Control Agent ◽  
Plant Diseases ◽  
White Mold ◽  
Malt Extract ◽  
Dual Culture ◽  
Potato Dextrose Broth ◽  
Inhibition Zones

Epicoccum nigrum is a potential biological control agent for certain plant diseases, such as white mold of bean caused by Sclerotinia sclerotiorum. To provide information that could be used to improve the production and efficacy of E. nigrum, the effects of nutrients, including specific carbohydrate sources and amino acids, on mycelial growth, sporulation, germination of conidia, and elongation of germ tubes were determined. In dual cultures of E. nigrum and S. sclerotiorum, the effects of nutrients on widths of inhibition zones between the two fungi were assessed. Standard mycological media supported faster radial growth than media with single carbohydrate sources and individual amino acids, but glutamic acid combined with maltose or dextrose was similar with respect to stimulation of sporulation when compared with media such as V8 juice and yeast extract agars. Dual culture inhibition zones were greater in certain simple media (dextrose and lysine, sucrose and lysine, and maltose and lysine) than in standard media. For germination and germ tube elongation, sucrose and maltose were superior to most other carbohydrate sources tested, and lysine and glutamic acid were superior amino acid sources. When standard broth media were compared for production of antifungal compounds by E. nigrum, both potato dextrose broth and malt extract broth were superior to Czapek solution. Culture filtrates of E. nigrum grown in potato dextrose broth were more inhibitory towards S. sclerotiorum than filtrates from malt extract cultures.Key words: biological control, white mold, Epicoccum purpurascens, antibiosis.

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