Virulence diversity of anthracnose pathogens (Colletotrichum acutatum and C. gloeosporioides species complexes) on eight olive cultivars commonly grown in Portugal

2014 ◽  
Vol 142 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Pedro Talhinhas ◽  
Elsa Gonçalves ◽  
S. Sreenivasaprasad ◽  
Helena Oliveira
Keyword(s):  
Colletotrichum Acutatum ◽  
Species Complexes ◽  
Olive Cultivars ◽  
Virulence Diversity

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

Agronomy ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 301 ◽  
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.

scholarly journals Assessing Rate-Reducing Foliar Resistance to Anthracnose Crown Rot and Fruit Rot in Strawberry

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 398-407 ◽  
Author(s):  
Raymond L. Jacobs ◽  
Tika B. Adhikari ◽  
Jeremy Pattison ◽  
G. Craig Yencho ◽  
Gina E. Fernandez ◽  
...  
Keyword(s):  
North Carolina ◽  
Durable Resistance ◽  
Crown Rot ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Breeding Lines ◽  
Progress Curve ◽  
Species Complexes ◽  
Controlled Environments ◽  
Strawberry Cultivars

Anthracnose fruit rot and anthracnose crown rot (ACR) caused by two species complexes of the fungus referred to as Colletotrichum acutatum and Colletotrichum gloeosporioides, respectively, are major pathogens of strawberry in North Carolina. Anthracnose epidemics are common when susceptible cultivars and asymptomatic planting stocks carrying quiescent Colletotrichum infection or hemibiotrophic infection (HBI) are planted. The main objective of this study was to assess resistance to HBI and ACR in strawberry. Strawberry cultivars and breeding lines were spray inoculated with isolates of C. acutatum or C. gloeosporioides. Four epidemiological parameters providing estimates of rate-reducing resistance to HBI and ACR in strawberry cultivars and lines were evaluated in repeated experiments in controlled environments in a greenhouse. HBI severity, measured as the percentage of total leaf area covered by acervuli, was estimated visually and by image analysis. ACR severity was rated weekly for wilt symptoms, and relative area under disease progress curve scores were calculated for comparing strawberry cultivars and lines. Significant differences (P ≤ 0.005) in HBI severity were found among strawberry genotypes; however, the correlations were not remarkable between Colletotrichum species (r = 0.4251). Although significant variation in resistance was observed for ACR, this was also weakly correlated (r = 0.2430) with resistance to C. gloeosporioides HBI. Overall, rate-reducing resistance to HBI and ACR in strawberry identified in this study could be utilized in breeding programs to develop durable resistance to anthracnose in North Carolina.

scholarly journals Elucidation of the Disease Cycle of Olive Anthracnose Caused by Colletotrichum acutatum

2009 ◽  
Vol 99 (5) ◽  
pp. 548-556 ◽  
Author(s):  
Juan Moral ◽  
Rodrígues de Oliveira ◽  
Antonio Trapero
Keyword(s):  
Latent Infection ◽  
Toxic Substance ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Phenological Stages ◽  
Disease Symptoms ◽  
Immature Fruit ◽  
Olive Cultivars ◽  
Detached Leaves ◽  
Branch Dieback

Anthracnose, caused by Colletotrichum acutatum and C. gloeosporioides, is a major fungal disease of olive in many countries. In Spain, the disease has been associated only with a characteristic rot and mummification of mature fruit. The purpose of this study was to determine whether C. acutatum could infect other plant tissues that may serve as sources of inoculum for anthracnose epidemics. Inoculations of young plants or detached leaves and field observations demonstrated that flowers and immature olive fruit are susceptible to the pathogen. Flower infection caused blight of inflorescences and infection of developing fruit. Immature fruit were infected in all phenological stages, although infection remained latent for 7 to 8 months, until the onset of fruit ripening. Fruit susceptibility increased and latent period decreased with maturity. Fruit were required for symptom development on inoculated plants. Plants without fruit were infected but they did not show any disease symptoms. Only plants with rotten fruit developed leaf wilting and branch dieback symptoms several weeks later. These results, together with the low level of pathogen isolation from affected leaves and branches and the toxicity of sterile fungal extracts to olive cuttings, suggest that a toxic substance produced by C. acutatum in rotten fruit may account for this syndrome. Both disease syndromes, fruit rot and branch dieback, developed in several olive cultivars, which were equally susceptible to the pathogen. However, olive cultivars differed in their response to flower and fruit infection. Latent infection of developing fruit during the spring may permit survival of the pathogen during the hot and dry summer and serve as an inoculum source for anthracnose epidemics that develop on ripening fruit in autumn.

A SYBR Green qPCR Method for Detecting and Quantifying Spores of Colletotrichum acutatum and C. gloeosporioides Species Complexes Causing Ripe Rot of Grape

2021 ◽  
Author(s):  
Scott Cosseboom ◽  
Mengjun Hu
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Cost Effective ◽  
Sybr Green ◽  
Colletotrichum Acutatum ◽  
Quantitative Real Time Pcr ◽  
Specific Primers ◽  
Green Method ◽  
Species Complexes ◽  
Qpcr Method ◽  
Spore Trapping

Four species belonging to Colletotrichum acutatum and Colletotrichum gloeosporioides species complexes, including C. aenigma, C. fioriniae, C. fructicola, and C. nymphaeae, were identified from ripe rot symptomatic fruit from Mid-Atlantic vineyards. A quantitative real-time PCR (qPCR) SYBR Green method was developed to detect and quantify conidia of the two Colletotrichum complexes to better understand the distribution and the extent of Colletotrichum inoculum. Primers were designed to specifically target the β-tubulin gene of the C. acutatum complex or the C. gloeosporioides complex and were found to be specific to the desired complex, not amplifying DNA of other prevalent fungi from vineyards. The sensitivity of the primers was also assessed, and the C. acutatum complex-specific and C. gloeosporioides complex-specific primers were able to quantify as little as 50 C. fioriniae conidia and 100 C. aenigma conidia, respectively. Therefore, this would be a cost-effective, specific, and sensitive detection and quantification method for these two destructive species complexes in vineyards and many other crops through spore trapping applications.

scholarly journals Influence of Fruit Maturity, Cultivar Susceptibility, and Inoculation Method on Infection of Olive Fruit by Colletotrichum acutatum

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1421-1426 ◽  
Author(s):  
J. Moral ◽  
K. Bouhmidi ◽  
A. Trapero
Keyword(s):  
Field Conditions ◽  
Colletotrichum Acutatum ◽  
Olive Fruit ◽  
Immature Fruit ◽  
Green Fruit ◽  
Inoculation Method ◽  
Controlled Conditions ◽  
Fruit Maturity ◽  
Olive Cultivars ◽  
Cultivar Susceptibility

Detached olive (Olea europaea) fruit inoculated with isolates of Colletotrichum acutatum, causal agent of olive anthracnose, were used to study host–pathogen interactions. Fruit susceptibility increased with increasing fruit maturity. Wounded fruit were more severely affected than nonwounded fruit; however, the wound effect depended on cultivar and inoculation method. Severity of fruit infection increased with inoculum density, although this effect also depended on fruit maturity and cultivar susceptibility. The susceptibility of selected olive cultivars to anthracnose under field conditions correlated well with the response of immature fruit under controlled conditions. As fruit matured, there were fewer differences among cultivars. Based on these results, an inoculation method using immature green fruit and high inoculum densities (105 to 106 conidia/ml) sprayed on the fruit has been proposed to evaluate olive cultivars for anthracnose resistance under controlled conditions.

scholarly journals Colletotrichum acutatum and C. gloeosporioides Species Complexes Associated with Apple in Brazil

Plant Disease ◽  
2019 ◽  
Vol 103 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Rafaele R. Moreira ◽  
Natalia A. Peres ◽  
Louise L. May De Mio
Keyword(s):  
Genomic Dna ◽  
Species Complex ◽  
Phylogenetic Trees ◽  
Rio Grande ◽  
Species Level ◽  
Colletotrichum Acutatum ◽  
Apple Orchards ◽  
Rio Grande Do Sul ◽  
Phylogenetic Species ◽  
Species Complexes

Glomerella leaf spot (GLS) is an apple disease that concerns growers due to the increases in severity over the years and the difficulties in control. Species within the Colletotrichum acutatum and C. gloeosporioides species complexes cause GLS, but the proportion of species within each complex in Brazilian apple orchards is not known. The objectives of this study were to identify isolates of Colletotrichum causing GLS on apple orchards in the main Brazilian producing regions to the species level. Two hundred and seven isolates were obtained in orchards in São Paulo (SP), Parana (PR), Santa Catarina (SC), and Rio Grande do Sul (RS) states. Genomic DNA was extracted, and the ITS, GAPDH, CHS-1, and TUB2 genes were amplified and sequenced. The phylogenetic trees were generated using a concatenated alignment. One hundred and fourteen isolates were identified as belonging to the C. acutatum species complex (Cac) and 93 to the C. gloeosporioides species complex (Cgc). Five phylogenetic species were identified: C. melonis (1.9%), C. nymphaeae (47.4%), C. paranaense (2.4%), C. limetticola (3.4%), and C. fructicola (44.9%). In SC, Cgc predominates, but in the states of SP, PR, and RS, Cac was predominant. This is the first report of C. limetticola from apple.

Sorting out the value of spectroscopic tools to assess the Colletotrichum acutatum impact in olive cultivars with different susceptibilities

2016 ◽  
Vol 30 (9) ◽  
pp. 548-558 ◽  
Author(s):  
Irene Gouvinhas ◽  
Nelson Machado ◽  
Amadeo Gironés-Vilaplana ◽  
Sónia Gomes ◽  
Teresa Carvalho ◽  
...  
Keyword(s):  
Colletotrichum Acutatum ◽  
Olive Cultivars

scholarly journals Sensitivity of Colletotrichum acutatum Isolates from Citrus to Carbendazim, Difenoconazole, Tebuconazole, and Trifloxystrobin

Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1621-1628 ◽  
Author(s):  
Andre B. Gama ◽  
Juliana S. Baggio ◽  
Carolina S. Rebello ◽  
Silvia de Afonseca Lourenço ◽  
Maria Cândida de G. Gasparoto ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Mycelial Growth ◽  
Conidial Germination ◽  
Colletotrichum Acutatum ◽  
Dilution Method ◽  
Quinone Outside Inhibitor ◽  
Fruit Drop ◽  
Species Complexes ◽  
Before And After ◽  
Dmi Fungicides

Postbloom fruit drop (PFD) of citrus is caused by the Colletotrichum acutatum and C. gloeosporioides species complexes. The disease is important when frequent rainfall occurs during the flowering period of citrus trees. In Brazil, until 2012, PFD was mainly controlled by preventive applications of the methyl-benzimidazole carbamate (MBC) carbendazim and demethylation-inhibitor (DMI) fungicides such as difenoconazole. Since then, mixtures containing the DMI tebuconazole and the quinone-outside inhibitor (QoI) trifloxystrobin have been commonly used. Fungicides are often applied preventively, sometimes even when conditions are not conducive for PFD development. Excessive fungicide applications may favor the selection of resistant populations of Colletotrichum spp. In this study, we assessed the fungicide sensitivity of C. acutatum isolates collected during the two distinct periods of PFD management in Brazil: before and after the trifloxystrobin and tebuconazole mixture became widely employed. The sensitivity of 254 C. acutatum isolates to carbendazim and difenoconazole and of 164 isolates to tebuconazole and trifloxystrobin was assessed. Mycelial growth inhibition of these isolates was evaluated for all the fungicides using either serial dilution of fungicide rates or the spiral gradient dilution method. In addition, inhibition of conidial germination was also assessed for trifloxystrobin. Analysis of partial β-tub, cytb, and cyp51b gene sequences did not reveal any mutations related to resistance to MBCs, QoIs, and DMIs, respectively. In mycelial growth assays, mean EC50 values were 0.14, 0.11, and 0.21 μg/ml for difenoconazole, tebuconazole, and trifloxystrobin, respectively. The conidial germination inhibition by trifloxystrobin was similar among the tested isolates, and the mean EC50 value was 0.002 μg/ml. All isolates had similar mean mycelial growth inhibition for carbendazim, regardless of the fungicide concentrations. Therefore, based on similar EC50 values and molecular analyses, no shift in the sensitivity of isolates has been observed to the fungicides commonly used in different citrus-producing areas in Brazil.

scholarly journals Assessing the Susceptibility of Olive Cultivars to Anthracnose Caused by Colletotrichum acutatum

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1028-1036 ◽  
Author(s):  
J. Moral ◽  
A. Trapero
Keyword(s):  
Disease Severity ◽  
Rating Scale ◽  
Laboratory Data ◽  
Assessment Method ◽  
Logistic Function ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Olive Cultivars ◽  
Progress Rate ◽  
Branch Dieback

Selected olive (Olea europaea) cultivars were tested in the field and laboratory for their relative susceptibility to anthracnose caused by Colletotrichum acutatum. A rating scale to assess fruit-rot incidence in naturally infected trees was validated by comparing ratings with direct counts of affected fruit. Fruit-rot incidence varied greatly among 20 cultivars and was correlated with the severity of branch dieback symptoms that developed after fruit-rot epidemics. For determining whether artificial inoculation can be used to predict anthracnose susceptibility in the orchard, detached fruit of 12 cultivars were inoculated with C. acutatum and fruit-rot severity was assessed periodically. Progress of disease severity over time fit the logistic function for all cultivars. The best correlation between fruit-rot incidence in the field and disease severity on inoculated fruit was obtained using a disease susceptibility index that integrated the maximum disease progress rate and the estimated time to reach 50% disease severity. Based on field observations and laboratory data on susceptibility to anthracnose, 21 cultivars were classified into three groups: highly susceptible (Cornicabra, Hojiblanca, Lechín de Sevilla, Manzanilla de Sevilla, Morona, Ocal, Picudo, and Verdial de Huévar); moderately susceptible (Arbequina, Arbosana, Morrut, Pajarero, and Villalonga); and resistant (Blanqueta, Empeltre, Frantoio, Koroneiki, Leccino, Morona-D, Picual, and Razzola). The assessment method may be useful to screen olive cultivars for anthracnose resistance.

scholarly journals Relative Susceptibility of New Olive Cultivars to Spilocaea oleagina, Colletotrichum acutatum, and Pseudocercospora cladosporioides

Plant Disease ◽  
2015 ◽  
Vol 99 (1) ◽  
pp. 58-64 ◽  
Author(s):  
J. Moral ◽  
M. Alsalimiya ◽  
L. F. Roca ◽  
C. M. Díez ◽  
L. León ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Rating Scale ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Relative Susceptibility ◽  
Negative Linear Correlation ◽  
Olive Cultivars ◽  
New Cultivars ◽  
Do So

The evaluation of the relative susceptibility of new cultivars to the main diseases of a crop is a key point to consider prior to their release to the nursery industry. This study provides a rigorous characterization of the resistance of 15 new olive cultivars and their genitors (‘Arbequina,’ ‘Frantoio,’ and ‘Picual’) to the three main aerial diseases, peacock spot, anthracnose, and cercosporiosis caused by Spilocaea oleagina, Colletotrichum acutatum, and Pseudocercospora cladosporioides, respectively. To do so, developing leaves and detached green-yellowish fruit were inoculated in laboratory tests with S. oleagina and C. acutatum, respectively, using conidial suspensions of both pathogens. Additionally, a previously validated rating scale was used to assess the incidence of leaves with symptoms of S. oleagina or P. cladosporioides and the fruit rot incidence of C. acutatum in the trees for four years under field conditions. As a result, only two of the cultivars were susceptible to peacock spot, most likely because these new cultivars were previously screened for resistance to the disease on previous phases of the breeding program. Conversely, the 15 cultivars were susceptible or moderately susceptible to cercosporiosis. Five of the 15 new cultivars were classified as resistant to anthracnose, with four of them descendants of ‘Frantoio’ × ‘Picual’ crosses. In addition, the cultivars resistance to C. acutatum showed a negative linear correlation with the total phenols content of olive oil. This information regarding disease reaction of the new olive cultivars is essential for nursery industry and growers.

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