Application of the consolidated species concept to identify the causal agent of strawberry anthracnose in Iran and initial molecular dating of the Colletotrichum acutatum species complex

Glomerella leaf spot (GLS) and bitter rot (BR) on apples are often caused by Colletotrichum acutatum in Paraná State, Brazil. GLS control is difficult because of its rapid development, with an incubation period of only 2 days under favorable conditions. Therefore, producers use successive fungicide applications every season; however, failure to control GLS has been commonly reported. The objectives of this study were to determine the sensitivity of isolates of the C. acutatum species complex obtained from apple orchards in Brazil to mancozeb, thiophanate-methyl, and azoxystrobin fungicides. Isolates from the different parts of the plant (leaves, flowers, buds, and twigs) and cultivars (Gala and Eva) showed different levels of sensitivity to mancozeb, thiophanate-methyl, and azoxystrobin. For mancozeb, the frequencies of isolates were 25% highly resistant, 50% low-resistance, and 25% sensitive. For thiophanate-methyl, the frequencies of isolates were 72.2% highly resistant, 11.1% resistant, and 16.7% moderately resistant. For azoxystrobin, the frequencies of isolates were 11.1% highly resistant, 5.6% resistant, and 83.3% sensitive. Interestingly, no mutations in the β-tubulin and cytochrome b genes were observed in any of the isolates resistant to thiophanate-methyl and azoxystrobin fungicides.

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Morphological, Pathogenic, and Molecular Characterization of Colletotrichum acutatum Isolates Causing Almond Anthracnose in Spain

Plant Disease ◽

10.1094/pdis-03-17-0318-re ◽

2017 ◽

Vol 101 (12) ◽

pp. 2034-2045 ◽

Cited By ~ 10

Author(s):

Ana López-Moral ◽

Maria Carmen Raya-Ortega ◽

Carlos Agustí-Brisach ◽

Luis F. Roca ◽

Maria Lovera ◽

...

Keyword(s):

Molecular Characterization ◽

Species Complex ◽

Morphological Characteristics ◽

Apple Fruit ◽

Colletotrichum Acutatum ◽

Pathogenicity Tests ◽

Clear Identification ◽

Colletotrichum Acutatum Species Complex ◽

A New Species

Almond anthracnose is a serious and emerging disease in several countries. All isolates causing almond anthracnose have been assigned to the Colletotrichum acutatum species complex, of which only C. fioriniae and C. godetiae have been associated with the disease to date. Here, we characterized Colletotrichum isolates from almond fruit affected by anthracnose in the Andalusia region. Two Colletotrichum isolates causing olive anthracnose were included for comparison. Morphological characteristics were useful for separating the isolates into groups based on colony morphology. Pathogenicity tests in almond, olive, and apple fruit showed differences in virulence and some degree of pathogenic specialization among isolates. Molecular characterization allowed clear identification of the Colletotrichum isolates tested. The olive isolates were identified as C. godetiae and C. nymphaeae, both previously identified in Andalusian olive orchards. Two phylogenetic species were identified among the almond isolates: C. godetiae, with gray colonies, which is well known in other countries, and C. acutatum, with pink-orange colonies. This species identification differs from those of pink-colony subpopulations described in other countries, which are C. fioriniae. Therefore, this study is also the first report of a new species of Colletotrichum causing almond anthracnose within the C. acutatum species complex.

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The Colletotrichum acutatum Species Complex as a Model System to Study Evolution and Host Specialization in Plant Pathogens

Frontiers in Microbiology ◽

10.3389/fmicb.2017.02001 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 19

Author(s):

Riccardo Baroncelli ◽

Pedro Talhinhas ◽

Flora Pensec ◽

Serenella A. Sukno ◽

Gaetan Le Floch ◽

...

Keyword(s):

Species Complex ◽

Plant Pathogens ◽

Model System ◽

Host Specialization ◽

Colletotrichum Acutatum ◽

Colletotrichum Acutatum Species Complex

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OCCURRENCE OF COLLETOTRICHUM ACUTATUM, CAUSE OF STRAWBERRY ANTHRACNOSE IN ISRAEL, AND MOLECULAR DIFFERENTIATION AMONG THE COLLETOTRICHUM SPECIES COMPLEX

Acta Horticulturae ◽

10.17660/actahortic.1997.439.133 ◽

1997 ◽

pp. 803-808

Author(s):

S. Freeman

Keyword(s):

Species Complex ◽

Colletotrichum Acutatum ◽

Colletotrichum Species ◽

Molecular Differentiation ◽

Strawberry Anthracnose

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Widespread Resistance to QoI Fungicides of Colletotrichum acutatum from Strawberry Nurseries and Production Fields

Plant Health Progress ◽

10.1094/php-08-18-0050-rs ◽

2018 ◽

Vol 19 (4) ◽

pp. 338-341 ◽

Cited By ~ 10

Author(s):

Bruna B. Forcelini ◽

Natalia A. Peres

Keyword(s):

United States ◽

Management Strategies ◽

The United States ◽

Colletotrichum Acutatum ◽

Qoi Fungicides ◽

The Past ◽

Resistant Population ◽

Strawberry Anthracnose ◽

Quinone Outside Inhibitors ◽

Colletotrichum Acutatum Species Complex

Strawberry anthracnose, caused mainly by the Colletotrichum acutatum species complex, is a major disease in strawberry nurseries and production fields. The use of fungicides, such as the quinone outside inhibitors (QoIs), has been extensively deployed for the control of C. acutatum for the past 20 years. C. acutatum resistance to the QoIs was first reported in 2013 in Florida strawberry production fields. In 2015, anthracnose outbreaks were reported in strawberry nurseries and production fields across the United States. To elucidate the significance and geographical extension of C. acutatum resistance, fungicide use surveys were conducted, and isolates were collected in the affected areas. QoI-resistant isolates were collected from strawberry production fields and nurseries in six states in the United States. Fungicide use surveys indicated that, in some locations, the number of QoI applications exceeded the recommendation for this fungicide group. Thus, the current situation warrants immediate changes in anthracnose management strategies that integrate other chemical as well as nonchemical strategies to limit resistant population selection and prevent future anthracnose outbreaks.

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The Colletotrichum acutatum species complex

Studies in Mycology ◽

10.3114/sim0010 ◽

2012 ◽

Vol 73 ◽

pp. 37-113 ◽

Cited By ~ 348

Author(s):

U. Damm ◽

P.F. Cannon ◽

J.H.C. Woudenberg ◽

P.W. Crous

Keyword(s):

Species Complex ◽

Colletotrichum Acutatum ◽

Colletotrichum Acutatum Species Complex

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Anthracnose Fruit and Root Necrosis of Strawberry Are Caused by a Dominant Species Within the Colletotrichum acutatum Species Complex in the United States

Phytopathology ◽

10.1094/phyto-12-18-0454-r ◽

2019 ◽

Vol 109 (7) ◽

pp. 1293-1301 ◽

Cited By ~ 7

Author(s):

Nan-Yi Wang ◽

Bruna B. Forcelini ◽

Natalia A. Peres

Keyword(s):

United States ◽

Species Complex ◽

The United States ◽

Fruit Rot ◽

Limiting Factors ◽

Colletotrichum Acutatum ◽

Genetic Characteristics ◽

Significant Difference ◽

Root Necrosis ◽

Strawberry Anthracnose

Strawberry anthracnose fruit rot and root necrosis, caused by Colletotrichum acutatum, are primary limiting factors in fruit production fields in the United States. Recent research focusing on the phenotypic and genetic characteristics of this species has shed light on the diversity of the C. acutatum species complex. In this study, we performed multilocus sequence analysis of four genetic loci to characterize 217 C. acutatum isolates collected over a 23-year period from symptomatic plant tissues of strawberry from six different states. The results revealed two Colletotrichum spp. (C. nymphaeae and C. fioriniae), with 97.7% of the isolate collection (212 of 217) belonging to C. nymphaeae as a dominant clonal linage, regardless of the isolation source. No correlation between species groups and geographical origins of the isolates was observed. Further sequence comparison between historical and contemporary isolates showed the same populations being widely distributed throughout the strawberry nurseries and production fields in the United States and Canada. Subsequently, a subset of 12 isolates representing different quinone-outside inhibitor fungicide resistance profiles from root or fruit tissue of strawberry was selected for comparison of pathogenicity on strawberry. In this test, isolates of different resistance groups or different isolation sources exhibited a similar degree of aggressiveness and caused indistinguishable symptoms on strawberry crowns (P = 0.9555 and 0.7873, respectively) and fruit (P = 0.1638 and 0.1141, respectively), although a significant difference among individual isolates was observed in detached-fruit assays (P = 0.0123). Separate pathogenicity tests using isolates of the two species revealed C. nymphaeae being more aggressive than C. fioriniae in infecting strawberry roots and crowns (P = 0.0073). Therefore, given the occurrence and pathogenicity of C. nymphaeae, this species is likely the sole cause responsible for strawberry anthracnose in the United States.

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