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

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

Plant Disease ◽

10.1094/pdis-93-10-1028 ◽

2009 ◽

Vol 93 (10) ◽

pp. 1028-1036 ◽

Cited By ~ 32

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.

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

Phytopathology ◽

10.1094/phyto-99-5-0548 ◽

2009 ◽

Vol 99 (5) ◽

pp. 548-556 ◽

Cited By ~ 33

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.

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FaRCa1 Confers Moderate Resistance to the Root Necrosis Form of Strawberry Anthracnose Caused by Colletotrichum acutatum

HortScience ◽

10.21273/hortsci14807-20 ◽

2020 ◽

Vol 55 (5) ◽

pp. 693-698 ◽

Cited By ~ 2

Author(s):

Natalia Salinas ◽

Zhen Fan ◽

Natalia Peres ◽

Seonghee Lee ◽

Vance M. Whitaker

Keyword(s):

Reference Genome ◽

Dna Marker ◽

Screening Method ◽

Fruit Rot ◽

Colletotrichum Acutatum ◽

Dna Test ◽

Root Necrosis ◽

Strawberry Anthracnose ◽

Moderate Resistance

FaRCa1 is a major locus conferring resistance to anthracnose fruit rot (AFR) caused by Colletotrichum acutatum, an important pathogen of strawberry (Fragaria ×ananassa). The objective of this study was to characterize the effects of FaRCa1 on anthracnose root necrosis (ARN) via root inoculations and DNA marker characterization of the locus. A subgenome-specific high-resolution melting (HRM) marker for an insertion/deletion (InDel) near FaRCa1 was designed using the ‘Camarosa’ octoploid reference genome. The marker was used to genotype cultivars and advanced selections studied in two seasons. A root disease screening method was developed in which roots were cut and dipped in a spore suspension before planting, using a mixture of three local isolates of the C. acutatum species complex. ARN was indirectly scored by calculating image-based leaf area differences among inoculated and noninoculated plants. The allele of FaRCa1 conferring resistance to AFR also conferred a significant reduction in ARN. Thus, a robust and easily scored DNA test is now available to breeders for selecting for resistance to both the fruit and root forms of strawberry anthracnose.

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Leaf Disk Infection by Colletotrichum acutatum and Its Relation to Fruit Rot in Diverse Blueberry Germplasm

HortScience ◽

10.21273/hortsci.41.1.270 ◽

2006 ◽

Vol 41 (1) ◽

pp. 270-271 ◽

Cited By ~ 6

Author(s):

Mark K. Ehlenfeldt ◽

James J. Polashock ◽

Allan W. Stretch ◽

Matthew Kramer

Keyword(s):

Leaf Disk ◽

Fruit Rot ◽

Colletotrichum Acutatum ◽

Good Resistance ◽

Vegetative Tissue ◽

Susceptibility Data ◽

Detached Leaf ◽

Foliar Resistance ◽

Low Levels ◽

New Cultivars

Response to foliar infection by Colletotrichum acutatum Simmonds ex Simmonds was assayed in a diverse group of 149 blueberry cultivars and selections using a detached leaf-disk assay. Disks were inoculated and incubated for one week, then were digitally imaged, and images analyzed for percent leaf decay. Infection percentages across cultivars averaged 32%, and ranged from 8% to 79%. The lowest levels of foliar infection were seen in the cultivars, Burlington, Sharpblue, and Berkeley. Foliar responses were compared to anthracnose fruit rot susceptibility data from a previous study. Several clones were observed to have low levels of both foliar and fruit infection. Cultivars with particularly good resistance to both phases included `Sharpblue', `Sunshine Blue', `Legacy', `Little Giant', `Flordablue', `Elliott', `Blue Ridge', `Blue Rose', and `November Glow'. Little correlation was observed between foliar response and fruit response to anthracnose infection (r = 0.15). Since C. acutatum overwinters primarily in vegetative tissue, breeding new cultivars with foliar resistance may assist in reducing inoculum levels of this disease under field conditions.

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Characterization of sludges. Protocol for organizing and conducting inter-laboratory tests of methods for chemical and microbiological analysis of sludges

10.3403/30131834u ◽

2015 ◽

Keyword(s):

Laboratory Tests ◽

Microbiological Analysis

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Towards Reduced CNNs for De-Noising Phase Images Corrupted with Speckle Noise

Photonics ◽

10.3390/photonics8070255 ◽

2021 ◽

Vol 8 (7) ◽

pp. 255

Author(s):

Marie Tahon ◽

Silvio Montresor ◽

Pascal Picart

Keyword(s):

Phase Error ◽

Speckle Noise ◽

Experimental Conditions ◽

Benchmark Data ◽

Wide Range ◽

Phase Images ◽

Different Depths ◽

Phase Data ◽

Do So

Digital holography is a very efficient technique for 3D imaging and the characterization of changes at the surfaces of objects. However, during the process of holographic interferometry, the reconstructed phase images suffer from speckle noise. In this paper, de-noising is addressed with phase images corrupted with speckle noise. To do so, DnCNN residual networks with different depths were built and trained with various holographic noisy phase data. The possibility of using a network pre-trained on natural images with Gaussian noise is also investigated. All models are evaluated in terms of phase error with HOLODEEP benchmark data and with three unseen images corresponding to different experimental conditions. The best results are obtained using a network with only four convolutional blocks and trained with a wide range of noisy phase patterns.

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Biochemical characterization of a cortexless mutant of a variant of Bacillus cereus

Canadian Journal of Microbiology ◽

10.1139/m76-147 ◽

1976 ◽

Vol 22 (7) ◽

pp. 1007-1012 ◽

Cited By ~ 2

Author(s):

Susanne M. Pearce

Keyword(s):

Cell Wall ◽

Fatty Acid Composition ◽

Fatty Acid ◽

Bacillus Cereus ◽

Biochemical Characterization ◽

Diaminopimelic Acid ◽

Peptidoglycan Synthesis ◽

Biochemical Lesion ◽

Do So

Previous studies on this cortexless mutant of Bacillus cereus var. alesti indicated that the forespore membrane was the site of the biochemical lesion. This hypothesis is supported by the results presented here: fatty acid composition of sporulating cells of the mutant is altered, while in vegetative cells it is comparable to the parent; soluble precursors of peptidoglycan synthesis are accumulated in the mutant, at the time of cortex formation; homogenates of the mutant prepared at the time of cortex formation are unable to incorporate tritiated diaminopimelic acid into peptidoglycan, while homogenates of cells forming germ cell wall do so to an extent comparable to that of the parent; lipid-linked intermediates are formed by the mutant as in the parent. Apparently the mutant is unable either to transfer disaccharide penta-peptide units from the carrier lipid to the growing peptidoglycan acceptor, or to transport lipid-linked intermediates across the forespore membrane.

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