Utilisation of immunochemical methods for detection of Colletotrichum spp. in strawberry

Four polyclonal and two monoclonal antibodies were prepared and tested to detect a quarantine pathogen of strawberry – Colletotrichum acutatum. Only one of them, polyclonal IgG K91, was sensitive enough to recognize the pathogen. This antibody was genus-specific and did not cross-react with several other fungal pathogens of strawberry (Phytophthora fragariae, P. cactorum, Verticillium albo-atrum, Botrytis cinerea, Pythium ultimum). Four techniques, PTA-ELISA, dot blot, immunoprint and immunofluorescent microscopy were used to test the specifity and sensitivity of antibodies. After artificial infection of strawberry (cvs Elsanta, Vanda, and Kama), Colletotrichum acutatum was detected by PTA-ELISA, dot blot and immunoprint in roots, crowns, petioles and fruits in the latent stage of the disease. For reliable detection in the latent stage it is recommended to use at least two of the mentioned techniques.

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Utilization of immunochemical methods to detect Phytophthora fraga-riae – a quarantine pathogen of strawberry

Plant Protection Science ◽

10.17221/8366-pps ◽

2001 ◽

Vol 37 (No. 2) ◽

pp. 57-65 ◽

Cited By ~ 2

Author(s):

B. Pekárová ◽

J. Krátká ◽

J. Slováček

Keyword(s):

Polyclonal Antibodies ◽

Pathogenic Fungi ◽

Pythium Ultimum ◽

Colletotrichum Acutatum ◽

Phytophthora Cactorum ◽

Dot Blot ◽

Quarantine Pathogen ◽

Phytophthora Fragariae ◽

Fusarium Sp ◽

Mycelial Mass

Polyclonal antibodies anti-PfP IgG and anti-PfM IgG and monoclonal antibody MAb29 were prepared to detect a quarantine pathogen of strawberry, Phytophthora fragariae. Laboratory rabbits and mice were immunized using purified and unpurified protein extracts from the mycelial mass of the pathogen. All prepared antibodies were genus-specific, therefore Phytophthora cactorum was also detected. Except for Pythium ultimum, the antibodies did not cross-react with other pathogenic fungi, such as Botrytis cinerea, Colletotrichum acutatum, Fusarium sp., Verticillium albo-atrum. PTA-ELISA was used to test the antibodies. P. fragariae was detected in artificially infected strawberries (cultivars Elsanta, Kama and Vanda) by means of PTA-ELISA, immunoprinting and dot blot. Detection of the pathogen was optimal in undamaged roots or roots with necrotic tips only. At a later stage of infection, when whole roots were necrotic, the crown was more suitable for successful detection. To detect P. fragariae at the early stages of infection it is recommended to use at least two of the three mentioned immunotechniques.

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The Use of Essential Oils from Thyme, Sage and Peppermint against Colletotrichum acutatum

Plants ◽

10.3390/plants10010114 ◽

2021 ◽

Vol 10 (1) ◽

pp. 114

Author(s):

Armina Morkeliūnė ◽

Neringa Rasiukevičiūtė ◽

Lina Šernaitė ◽

Alma Valiuškaitė

Keyword(s):

Essential Oils ◽

Fungal Pathogens ◽

Control Plant ◽

Antimicrobial Activities ◽

Plant Diseases ◽

Colletotrichum Acutatum ◽

Low Toxicity ◽

Colletotrichum Spp ◽

Biological Protection

The Colletotrichum spp. is a significant strawberry pathogen causing yield losses of up to 50%. The most common method to control plant diseases is through the use of chemical fungicides. The findings of plants antimicrobial activities, low toxicity, and biodegradability of essential oils (EO), make them suitable for biological protection against fungal pathogens. The aim is to evaluate the inhibition of Colletotrichum acutatum by thyme, sage, and peppermint EO in vitro on detached strawberry leaves and determine EO chemical composition. Our results revealed that the dominant compound of thyme was thymol 41.35%, peppermint: menthone 44.56%, sage: α,β-thujone 34.45%, and camphor: 20.46%. Thyme EO inhibited C. acutatum completely above 200 μL L−1 concentration in vitro. Peppermint and sage EO reduced mycelial growth of C. acutatum. In addition, in vitro, results are promising for biological control. The detached strawberry leaves experiments showed that disease reduction 4 days after inoculation was 15.8% at 1000 μL L−1 of peppermint EO and 5.3% at 800 μL L−1 of thyme compared with control. Our findings could potentially help to manage C. acutatum; however, the detached strawberry leaves assay showed that EO efficacy was relatively low on tested concentrations and should be increased.

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Inhibition of Fungal Growth by Macerated Plant Tissues in a Closed Environment

HortScience ◽

10.21273/hortsci.33.3.476e ◽

1998 ◽

Vol 33 (3) ◽

pp. 476e-476

Author(s):

Craig S. Charron ◽

Catherine O. Chardonnet ◽

Carl E. Sams

Keyword(s):

Radial Growth ◽

Fungal Pathogens ◽

Solid Phase ◽

Indian Mustard ◽

Fungal Growth ◽

Allyl Isothiocyanate ◽

Pythium Ultimum ◽

Alternative Methods ◽

Gas Chromatography Mass Spectrometry ◽

Clean Air

The U.S. Clean Air Act bans the use of methyl bromide after 2001. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of macerated tissues of Brassica spp. This study tested the potential of several Brassica spp. for control of fungal pathogens. Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar on petri dishes were sealed in 500-ml glass jars (at 22 °C) containing macerated leaves (10 g) from one of six Brassica spp. Radial growth was measured 24, 48, and 72 h after inoculation. Indian mustard (B. juncea) was the most suppressive, followed by `Florida Broadleaf' mustard (B. juncea). Volatile compounds in the jars were sampled with a solid-phase microextraction device (SPME) and identified by gas chromatography-mass spectrometry (GC-MS). Allyl isothiocyanate (AITC) comprised over 90% of the total volatiles measured from Indian mustard and `Florida Broadleaf' mustard. Isothiocyanates were detected in jars with all plants except broccoli. (Z)-3-hexenyl acetate was emitted by all plants and was the predominant volatile of `Premium Crop' broccoli (B. oleracea L. var. italica), `Michihili Jade Pagoda' Chinese cabbage (B. pekinensis), `Charmant' cabbage (B. oleracea L. var. capitata), and `Blue Scotch Curled' kale (B. oleracea L. var. viridis). To assess the influence of AITC on radial growth of P. ultimum and R. solani, AITC was added to jars to give headspace concentrations of 0.10, 0.20, and 0.30 mg·L–1 (mass of AITC per volume of headspace). Growth of both fungi was inhibited by 0.10 mg·L–1 AITC. 0.20 mg·L–1 AITC was fungicidal to P. ultimum although the highest AITC level tested (0.30 mg·L–1) did not terminate R. solani growth. These results indicate that residues from some Brassica spp. may be a viable part of a soilborne pest control strategy.

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The Root Rot-Fusarium Wilt Complex of Peas

Australian Journal of Biological Sciences ◽

10.1071/bi9630055 ◽

1963 ◽

Vol 16 (1) ◽

pp. 55 ◽

Cited By ~ 50

Author(s):

A Kerr

Keyword(s):

Fusarium Oxysporum ◽

Fusarium Wilt ◽

Root Rot ◽

Fungal Pathogens ◽

South Australia ◽

Pythium Ultimum ◽

Wilt Symptom ◽

Intensive Cropping ◽

Race 2

At least four fungal pathogens are involved in the root rot-Fusarium wilt complex of peas which is a serious problem following intensive cropping of peas in South Australia. The pathogens are Fusarium oxysporum f. pisi race 2 Snyder & Hansen, F. solani f. pisi Snyder & Hansen, Pythium ultimum Trow, and Ascochyta pinodella L. K. Jones. In susceptible pea cultivars there is a marked interaction between F. oxysporum and P. ultimum. P. ultimum alone causes initial stunting from which plants gradually recover; F. OX1Jsporum alone probably CRuses little damage; both fungi together CRuse initial stunting followed by severe wilt symptom about 6 weeks after sowing and death 2 weeks later. The importance ofF. solani and A. pinodella has not been fully determined, but they probably cause only minor damage.

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Sensitivity of Colletotrichum Species, Including C. fioriniae and C. nymphaeae, from Peach to Demethylation Inhibitor Fungicides

Plant Disease ◽

10.1094/pdis-04-16-0574-re ◽

2016 ◽

Vol 100 (12) ◽

pp. 2434-2441 ◽

Cited By ~ 15

Author(s):

S. N. Chen ◽

C. X. Luo ◽

M. J. Hu ◽

G. Schnabel

Keyword(s):

South Carolina ◽

Colletotrichum Acutatum ◽

In Vitro Activity ◽

Internal Transcribed Spacer Region ◽

Control Efficacy ◽

Dmi Fungicides ◽

Colletotrichum Spp ◽

Colletotrichum Acutatum Species Complex ◽

Demethylation Inhibitor

Few fungicides are effective against anthracnose, caused by Colletotrichum spp., and emerging resistance makes the search for chemical alternatives more relevant. Isolates of the Colletotrichum acutatum species complex were collected from South Carolina and Georgia peach orchards and phylogenetic analysis of the combined internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, and β-tubulin gene sequences separated the isolates into C. nymphaeae and C. fioriniae. The sensitivity of these and three other previously reported Colletotrichum spp. from peach, including C. fructicola, C. siamense, and C. truncatum, to demethylation inhibitor (DMI) fungicides difenoconazole, propiconazole, tebuconazole, metconazole, flutriafol, and fenbuconazole was determined based upon mycelial growth inhibition. C. truncatum was resistant to tebuconazole, metconazole, flutriafol, and fenbuconazole and C. nymphaeae was resistant to flutriafol and fenbuconazole based on 50% effective concentration (EC50) values >100 μg/ml. C. fructicola and C. siamense were sensitive to all DMI fungicides (EC50 values of 0.2 to 13.1 μg/ml). C. fioriniae subgroup 2 isolates were less sensitive to DMI fungicides (EC50 values of 0.5 to 16.2 μg/ml) compared with C. fioriniae subgroup 1 (EC50 values of 0.03 to 2.1 μg/ml). Difenoconazole and propiconazole provided the best control efficacy in vitro to all five species, with EC50 values of 0.2 to 2.7 μg/ml. Tebuconazole and metconazole were effective against all Colletotrichum spp., except for C. truncatum. The strong in vitro activity of some DMI fungicides against Colletotrichum spp. may be exploited for improved anthracnose disease management of peach.

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Diversity of Colletotrichum Species Associated with Olive Anthracnose and New Perspectives on Controlling the Disease in Portugal

Agronomy ◽

10.3390/agronomy8120301 ◽

2018 ◽

Vol 8 (12) ◽

pp. 301 ◽

Cited By ~ 4

Author(s):

Patrick Materatski ◽

Carla Varanda ◽

Teresa Carvalho ◽

António Bento Dias ◽

M. Doroteia Campos ◽

...

Keyword(s):

Severe Disease ◽

Colletotrichum Acutatum ◽

High Similarity ◽

Flower Buds ◽

Vegetative Organs ◽

Nucleotide Mutation ◽

Olive Cultivars ◽

Colletotrichum Spp ◽

Olive Trees ◽

Working Out

Olive anthracnose is a very common and severe disease caused by diverse species of fungi belonging to Colletotrichum acutatum and Colletotrichum gloeosporioides complexes. To understand aspects of the Colletotrichum colonization and primary infection in olives, Colletotrichum spp. were isolated from the interior of 2-year stems, flower buds, and immature fruits of three important olive cultivars, Galega vulgar, Cobrançosa, and Azeiteira, from different sites within Alentejo, a major olive-producing region in Portugal. A total of 270 trees was sampled, and 68 Colletotrichum spp. isolates were obtained from 46 olive trees. DNA extraction and amplification of β-tubulin and GADPH genes through PCR revealed that the vast majority of the isolates showed high similarity to Colletotrichum nymphaeae, and only three isolates showed high similarity to Colletotrichum godetiae. The highest number of Colletotrichum spp. isolates was detected in olive trees from Galega vulgar and in immature fruits. No significant differences in the number of Colletotrichum spp. isolates were found in trees from different sites. The highest percentages of infected immature fruits were obtained in trees that also presented a high percentage of 2-year stem infections, which may indicate that 2-year stems serve as important sources of inoculum, and the fungus may travel from the stems to other parts of the plant. Another indication of such possibility is that one isolate of C. nymphaeae (C. nymphaeae 2), characterized by a unique nucleotide mutation within the beta tubulin gene, was present in different organs of the same tree, both in 2-year stems and in recently formed vegetative organs as flower buds and immature fruits, which seem to suggest that it may be the same isolate, which has moved systemically inside the plant. The results presented here can play an important role in working out strategies for the effective and timely management of the disease and in reducing the number of unnecessary fungicide applications.

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Assessment of Fungal Pathogens Affecting the Weed Conyza bonariensis in Argentina

Journal of Agricultural Science ◽

10.5539/jas.v10n3p62 ◽

2018 ◽

Vol 10 (3) ◽

pp. 62

Author(s):

Martin Bonacci ◽

Ángela N. Formento ◽

Fernando Daita ◽

Melina Sartori ◽

Miriam Etcheverry ◽

...

Keyword(s):

Fungal Pathogens ◽

Alternative Methods ◽

Weed Species ◽

Koch’S Postulates ◽

Fungal Isolates ◽

Conyza Bonariensis ◽

Pesticide Reduction ◽

Colletotrichum Spp ◽

And Control ◽

Koch's Postulates

In the last years Conyza bonariensis has become an important weed and control is difficult with the use of current technology in Argentinean pampas region. The increasing prevalence of herbicide-resistant weed species, public concern related to pesticide use and the introduction of government policies for pesticide reduction, is driving the search for alternative methods to chemical control. The aims of the present study were to detect fungal diseases associated with C. bonariensis, to identify fungal isolates from the symptomatic leaves and to confirm through Koch’s postulates the isolates pathogenicity. Mycological analysis of symptomatic leaves showed the presence of twelve genera of filamentous fungi. Among 116 isolates, Colletotrichum spp. was the most prevalent genus followed by Nigrospora spp. and Septoria spp. In the pathogenicity assays, 22 out of 116 isolates were able to comply with the Koch’s postulates. The pathogenic isolates were included into three genera Alternaria spp., Colletotrichum spp. and Septoria spp. This study provides the first report that demonstrates pathogenicity of fungal isolates on C. bonariensis in Argentina and represents the first step in a future biocontrol program.

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Caenorhabditis elegans as an Emerging Model for Virus-Host Interactions

Journal of Virology ◽

10.1128/jvi.00509-17 ◽

2017 ◽

Vol 91 (23) ◽

Cited By ~ 10

Author(s):

Don B. Gammon

Keyword(s):

Caenorhabditis Elegans ◽

Virus Infection ◽

Fungal Pathogens ◽

Model Organism ◽

Artificial Infection ◽

Viral Pathogen ◽

Content Type ◽

Host Interactions ◽

C Elegans ◽

Infection Models

ABSTRACT Since 1999, Caenorhabditis elegans has been extensively used to study microbe-host interactions due to its simple culture, genetic tractability, and susceptibility to numerous bacterial and fungal pathogens. In contrast, virus studies have been hampered by a lack of convenient virus infection models in nematodes. The recent discovery of a natural viral pathogen of C. elegans and development of diverse artificial infection models are providing new opportunities to explore virus-host interplay in this powerful model organism.

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Control of Postharvest Fungal Pathogens by Antifungal Compounds from Penicillium expansum

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-072 ◽

2013 ◽

Vol 76 (11) ◽

pp. 1879-1886 ◽

Cited By ~ 20

Author(s):

WAFA ROUISSI ◽

LUISA UGOLINI ◽

CAMILLA MARTINI ◽

LUCA LAZZERI ◽

MARTA MARI

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Fungal Pathogens ◽

Solid Phase ◽

Petri Dish ◽

Pathogenic Fungi ◽

Penicillium Expansum ◽

Colletotrichum Acutatum ◽

Volatile Organic

The fungicidal effects of secondary metabolites produced by a strain of Penicillium expansum (R82) in culture filtrate and in a double petri dish assay were tested against one isolate each of Botrytis cinerea, Colletotrichum acutatum, and Monilinia laxa and six isolates of P. expansum, revealing inhibitory activity against every pathogen tested. The characterization of volatile organic compounds released by the R82 strain was performed by solid-phase microextraction–gas chromatographic techniques, and several compounds were detected, one of them identified as phenethyl alcohol (PEA). Synthetic PEA, tested in vitro on fungal pathogens, showed strong inhibition at a concentration of 1,230 μg/ml of airspace, and mycelium appeared more sensitive than conidia; nevertheless, at the concentration naturally emitted by the fungus (0.726 ± 0.16 μg/ml), commercial PEA did not show any antifungal activity. Therefore, a combined effect between different volatile organic compounds produced collectively by R82 can be hypothesized. This aspect suggests further investigation into the possibility of exploiting R82 as a nonchemical alternative in the control of some plant pathogenic fungi.

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Inhibition of Pythium ultimum and Rhizoctonia solani by Shredded Leaves of Brassica Species

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.124.5.462 ◽

1999 ◽

Vol 124 (5) ◽

pp. 462-467 ◽

Cited By ~ 52

Author(s):

Craig S. Charron ◽

Carl E. Sams

Keyword(s):

Rhizoctonia Solani ◽

Fungal Pathogens ◽

Solid Phase ◽

Indian Mustard ◽

Allyl Isothiocyanate ◽

Brassica Species ◽

Pythium Ultimum ◽

Alternative Methods ◽

Gas Chromatography Mass Spectrometry ◽

Freeze Dried

The U.S. Clean Air Act bans the use of methyl bromide after 2005. Consequently, the development of alternative methods for control of soilborne pathogens is imperative. One alternative is to exploit the pesticidal properties of Brassica L. species. Macerated leaves (10 g) from `Premium Crop' broccoli [B. oleracea L. (Botrytis Group)], `Charmant' cabbage [B. oleracea L. (Capitata Group)], `Michihili Jade Pagoda' Chinese cabbage [B. rapa L. (Pekinensis Group)], `Blue Scotch Curled' kale [B. oleracea L. (Acephala Group)], Indian mustard [B. juncea (L.) Czerniak, unknown cultivar] or `Florida Broadleaf' mustard [B. juncea (L.) Czerniak] were placed in 500-mL glass jars. Petri dishes with either Pythium ultimum Trow or Rhizoctonia solani Kühn plugs on potato-dextrose agar were placed over the jar mouths. Radial growth of both fungi was suppressed most by Indian mustard. Volatiles were collected by solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry. Allyl isothiocyanate (AITC) comprised >90% of the volatiles measured from `Florida Broadleaf' mustard and Indian mustard whereas (Z)-3-hexenyl acetate was the predominant compound emitted by the other species. Isothiocyanates were not detected by SPME from `Premium Crop' broccoli and `Blue Scotch Curled' kale although glucosinolates were found in freeze-dried leaves of all species. When exposed to AITC standard, P. ultimum growth was partially suppressed by 1.1 μmol·L-1 (μmol AITC/headspace volume) and completely suppressed by 2.2 μmol·L-1 R. solani was partially suppressed by 1.1, 2.2, and 3.3 μmol·L-1 AITC. Use of Brassica species for control of fungal pathogens is promising; the presence of AITC in both lines of B. juncea suppressed P. ultimum and R. solani but some Brassicas were inhibitory even when isothiocyanates were not detected.

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