First Report of Ascochyta Blight Outbreak of Pea Caused by Ascochyta pisi in Spain

Characteristic Ascochyta blight lesions were observed on leaves and stems of pea (Pisum sativum L.) ‘Dove’ grown at two sites in the province of Burgos (northern Spain) during May and June of 2005 and 2006. Mean disease severity of affected tissue reached 47% in 2005 and 72% in 2006. Dark brown, circular, necrotic lesions were sometimes covered with pycnidia. Fungal isolations were made from small pieces of infected tissue by surface disinfecting in 1% NaOCl for 1 min and then washing in deionized, sterile water for 2 min. Tissue pieces were placed on potato dextrose agar (PDA) for 7 days at 20 to 24°C under fluorescents lights with a 12-h photoperiod to induce sporulation. Single-spore isolations were made by streaking conidia from PDA cultures on 2% water agar and picking germinated conidia after 18 h. Fungal colonies grown on PDA and conidia from these cultures were similar to that of Ascochyta pisi Lib., and no chlamydospores or pseudothecia were observed, eliminating the possibility that the isolated fungi were A. pinodes or A. pinodella (3), the other fungi associated with the “Ascochyta complex” of pea. Conidial suspensions (5 × 105 conidia/ml) of two single-spore isolates (Spain-47 and Spain-48) were spray inoculated to runoff on 3-week-old plants of bean (Phaseolus vulgaris L. ‘Contender’), chickpea (Cicer arietinum L. ‘Blanco lechoso’), lentil (Lens culinaris Medik. ‘Pardinar’), pea (‘Lincoln’), and faba bean (Vicia faba L. ‘Alameda’) with 10 replicate plants per isolate. Plants were incubated in a growth chamber at 20 to 24°C and 100% relative humidity (RH) for 48 h and then incubated at the same temperature and 50 to 80% RH for 3 weeks. Characteristic Ascochyta blight lesions were apparent 7 days after inoculation on leaves and stems of pea. No disease symptoms were observed on the other inoculated plants. DNA was extracted from both isolates (Spain-47 and Spain-48) and 610 bp of the glyceraldehyde-3-phosphate-dehydrogenase gene (G3PD) was amplified with gpd-1 and gpd-2 primers (2). Amplicons were direct sequenced on both strands and consensus sequences were aligned. Spain-47 and Spain-48 had identical sequences. A BLAST search of the NCBI nucleotide database with the consensus sequence revealed A. pisi G3PD Accession No. DQ383963 (isolate ATCC 201617, Bulgaria) as the closest match in the database with 100% sequence similarity. These results, coupled with the morphological identification and inoculation results, confirm the identity of the fungus as A. pisi. Although infections by A. pinodes or by unidentified Ascochyta spp. are well known in pea crops in Spain (1), to our knowledge, this is the first report of an outbreak of Ascochyta blight of pea caused by A. pisi under field conditions in Spain. References: (1) M. F. Andrés et al. Patógenos de Plantas Descritos en España. MEC, Madrid, 1998. (2) M. L. Berbee et al. Mycologia 91:964, 1999. (3) E. Punithalingam and P. Holliday. No 334 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.

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First Report of Ascochyta Blight of Vicia hirsuta (Hairy Tare) in the Republic of Georgia Caused by Ascochyta sp

Plant Disease ◽

10.1094/pd-90-1555a ◽

2006 ◽

Vol 90 (12) ◽

pp. 1555-1555 ◽

Cited By ~ 1

Author(s):

M. I. Chilvers ◽

T. L. Horton ◽

T. L. Peever ◽

W. J. Kaiser ◽

F. J. Muehlbauer

Keyword(s):

Sequence Similarity ◽

Ascochyta Blight ◽

Pathogenic Fungi ◽

Ascochyta Rabiei ◽

Morphological Identification ◽

Conidial Suspension ◽

Republic Of Georgia ◽

First Report ◽

Vicia Hirsuta ◽

The Republic

Tan lesions with dark margins containing concentric rings of black pycnidia were observed on leaves and pods of hairy tare (Vicia hirsuta L.) growing near Ateni, GA (41°54.631′N, 44°05.586′E, elev. 730 m) on 1 July 2004. Lesions were reminiscent of those induced by Ascochyta rabiei (Pass.) Labrousse on chickpea (Cicer arietinum L.). At the time of collection, necrotic lesions were observed on the stems, leaflets, and pods of several plants. The fungus was isolated by surface-disinfecting small pieces of infected tissue in 95% EtOH for 10 s, 1% NaOCl for 1 min, and then deionized H20 for 1 min. Tissue pieces were placed on 3% water agar (WA) for 24 h under fluorescent lights with a 12-h photoperiod to induce sporulation. Single-conidial isolations were made by streaking cirrhi on 3% WA and picking germinated single conidia. After 14 days of growth, the isolated fungus had colony morphology similar to that of A. rabiei on V8 juice agar. A conidial suspension of the fungus (1 × 105 conidia/ml) was spray-inoculated onto 2-week-old plants including PI lines 628303, 628304, 420171, and 422499 of V. hirsuta and C. arietinum cv. Burpee. Plants were obtained from the USDA Western Region Plant Introduction Station, Pullman, WA, and 20 replicate plants of each genotype were inoculated. Inoculated plants were covered with a plastic cup to maintain high humidity and incubated in a growth chamber for 48 h at 18°C. Following removal of the cups, characteristic Ascochyta blight lesions were apparent 14 days after inoculation on both plant species. DNA was extracted from the isolate and 610 bp of the glyceraldehyde-3-phosphate-dehydrogenase gene (G3PD), 364 bp of the chitin synthase 1 gene, and 330 bp of the translation elongation factor 1-alpha gene were amplified with gpd-1 and gpd-2 primers (1), CHS-79 and CHS-354 primers (2), and EF1-728F and EF1-986R primers (2), respectively. Amplicons were direct sequenced on both strands and a BLAST search of the NCBI nucleotide database with consensus G3PD, CHS, and EF sequences revealed the chickpea pathogen Didymella rabiei (anamorph Ascochyta rabiei) accessions DQ383958, DQ386480, and DQ386488 as the closest matches in the databases with 95, 95, and 88% sequence similarity, respectively. These results, coupled with the morphological identification and the inoculation results, confirm the identity of the fungus as Ascochyta sp. Further research needs to be performed to determine if this represents a new species of Ascochyta. The identification of this fungus is part of a larger project to develop a phylogeny for Ascochyta spp. infecting cultivated legumes and their wild relatives that will provide a framework for the study of the evolution of host specificity and speciation of plant-pathogenic fungi. This is the second report of an Ascochyta species on V. hirsuta, and to our knowledge, the first report of Ascochyta blight of this host in the Republic of Georgia. References: (1) M. L. Berbee et al. Mycologia 91:964, 1999. (2) I. Carbone and L. M. Kohn. Mycologia 91:553, 1999.

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First Report of Ascochyta Blight of Pisum elatius (Wild Pea) in the Republic of Georgia Caused by Ascochyta pisi

Plant Disease ◽

10.1094/pdis-91-3-0326b ◽

2007 ◽

Vol 91 (3) ◽

pp. 326-326 ◽

Cited By ~ 1

Author(s):

M. I. Chilvers ◽

T. L. Horton ◽

T. L. Peever ◽

W. J. Kaiser ◽

F. J. Muehlbauer

Keyword(s):

Ascochyta Blight ◽

Elongation Factor ◽

Plant Introduction ◽

Morphological Identification ◽

Republic Of Georgia ◽

Translation Elongation ◽

First Report ◽

Site Characteristics ◽

Ascochyta Pisi ◽

The Republic

Characteristic Ascochyta blight lesions were observed on leaves and pods of wild pea (Pisum elatius Steven. ex M. Bieb.) growing at three sites in the Republic of Georgia during June and July of 2004. Site characteristics were 41°36.11′N, 44°31.34′E (elevation 919 m), 41°54.221′N, 44°05.667′E (elevation 744 m), and 41°44.907′N, 43°12.263′E (elevation 884 m). Lesions appeared similar to those induced by Ascochyta pisi Lib. on cultivated pea (P. sativum L.). Fungi were isolated by surface disinfesting small pieces of infected tissue in 95% EtOH for 10 s, 1% NaOCl for 1 min, and then in deionized sterile H20 for 1 min. Tissue pieces were placed on 3% water agar (WA) for 24 h under fluorescent lights with a 12-h photoperiod to induce sporulation. Single-conidial isolations were made by streaking conidia on 3% WA and picking germinated conidia 18 h later. Three fungi (isolates Georgia-6, -7, and -12) had colony morphology similar to that of A. pisi on V8 juice agar. Conidial suspensions (1 × 105 conidia/ml) of each isolate above were spray inoculated to runoff on three genotypes of 2-week-old P. elatius plants. Plants inoculated included PI lines 560055 and 513252 and W6 line 15006 from the USDA Western Region Plant Introduction Station, Pullman, WA with 11 replicate plants inoculated per isolate. Plants were incubated in a growth chamber for 48 h at 18°C and covered with a plastic cup to maintain high humidity. Characteristic Ascochyta blight lesions were apparent 7 days after inoculation. DNA was extracted from each isolate and 610 bp of the glyceraldehyde-3-phosphate-dehydrogenase gene (G3PD), 364 bp of chitin synthase 1, and 330 bp of the translation elongation factor 1-alpha gene were amplified with gpd-1 and gpd-2 primers (1), CHS-79 and CHS-354 primers (2), and EF1-728F and EF1-986R primers (2), respectively. Amplicons were direct sequenced on both strands, and BLAST searches of the NCBI nucleotide database with consensus G3PD, CHS, and EF sequences of isolates Georgia-6, -7, and -12 were performed. The closest match obtained for the G3PD sequences was A. pisi isolate ATCC 201617 (Accession No. DQ383963). G3PD sequences for Georgia-6, -7, and -12 were deposited in GenBank (Accession Nos. DQ383966 [Georgia-6 and -7] and DQ383963 [A. pisi isolate AP1 and Georgia-12]). Closest matches to CHS and EF sequences were A. pisi isolate ATCC 201618 (EF Accession No. DQ386494) and Didymella fabae isolate ATCC 96418 (CHS Accession No. DQ386481, EFAccession No. DQ386492), respectively. CHS sequences for Georgia-6, -7, and -12 were identical to each other and to A. fabae isolate AF1 and were deposited in GenBank (Accession No. DQ386481. EF sequences for Georgia-6, -7, and -12 were deposited in GenBank (Accession Nos. DQ386494 [Georgia-6 and A. pisi isolate AP2], DQ386495, and DQ386496, respectively. These results, coupled with the morphological identification and inoculation results, confirm the identity of the fungus as A. pisi. To our knowledge, this is the first report of Ascochyta blight of P. elatius in the Republic of Georgia. References: (1) M. L. Berbee et al. Mycologia 91:964. 1999. (2) I. Carbone and L. M. Kohn. Mycologia 91:553, 1999.

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First Report of Ascochyta Blight of Field Pea Caused by Ascochyta pisi in South Dakota

Plant Disease ◽

10.1094/pdis-94-6-0789a ◽

2010 ◽

Vol 94 (6) ◽

pp. 789-789 ◽

Cited By ~ 1

Author(s):

F. M. Mathew ◽

R. S. Goswami ◽

S. G. Markell ◽

L. Osborne ◽

C. Tande ◽

...

Keyword(s):

South Dakota ◽

Consensus Sequence ◽

Ascochyta Blight ◽

Its Region ◽

The United States ◽

Field Pea ◽

Conidial Suspension ◽

First Report ◽

Production Region ◽

Ascochyta Pisi

Tan lesions approximately 1.7 × 0.8 cm with distinct dark brown margins and small pycnidia were observed on leaves of field peas (Pisum sativum L. ‘Agassiz’) growing in Campbell County, South Dakota (45°45.62′N, 100°9.13′W) in July 2008. Small pieces of symptomatic leaves were surface sterilized (10% NaOCl for 1 min, 70% EtOH for 1 min, and sterile distilled H2O for 2 min) and placed on potato dextrose agar (PDA) for 7 days under fluorescent lights with a 12-h photoperiod to induce sporulation. A pure culture was established by streaking a conidial suspension on PDA and isolating a single germinated spore 3 days later. The culture was grown on clarified V8 media for 10 days. Conidia were 10 to 16 × 3 to 4.5 μm and uniseptate with a slightly constricted septum, similar to those of Ascochyta pisi Lib. The exuding spore mass from pycnidia growing on the medium was carrot red. No chlamydospores or pseudothecia were observed (1,2). To confirm the identity of A. pisi, DNA was extracted from the lyophilized mycelium of the 10-day-old culture with the DNeasy Plant Mini Kit (Qiagen, Valencia, CA). Internal transcribed spacer (ITS) regions I and II were amplified with PCR primers ITS 5 and ITS 4 (3). PCR amplicons were cleaned and directly sequenced in both directions using the primers. A BLASTN search against the NCBI nonredundant nucleotide database was performed using the consensus sequence generated by alignment of the forward and reverse sequences for this region. The consensus sequence (GenBank Accession No. GU722316) most closely matched A. pisi var. pisi strain (GenBank Accession No. EU167557). These observations confirm the identity of the fungus as A. pisi. A suspension of 1 × 106 conidia/ml of the isolate was spray inoculated to runoff on 10 replicate plants of 2-week-old, susceptible green field pea ‘Sterling’. Plants were incubated in a dew chamber for 48 h at 18°C and moved to the greenhouse bench where they were maintained at 20 to 25°C with a 12-h photoperiod for 1 week. Tan lesions with dark margins appeared 7 days after inoculation and disease was assessed after 10 days (4). No symptoms were observed on water-treated control plants. A. pisi was reisolated from lesions and confirmed by DNA sequencing of the ITS region, fulfilling Koch's postulates. Currently, states bordering South Dakota (North Dakota and Montana) lead the United States in field pea production. Although acreage is limited in South Dakota, the identification of A. pisi in this region is serious. The disease is yield limiting and foliar fungicides are used for disease management (1). To our knowledge, this is the first report of Ascochyta blight on P. sativum caused by A. pisi occurring in South Dakota and the MonDak production region (the Dakotas and Montana). References: (1) T. W. Bretag et al. Aust. J. Agric. Res. 57:88, 2006. (2) A. S. Lawyer. Page 11 in: The Compendium of Pea Diseases. D. J. Hagedorn, ed. The American Phytopathological Society, St Paul, MN, 1984. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990. (4) J. M. Wroth. Can. J. Bot. 76:1955, 1998.

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Morphological and Genotypic Characterization of Fungi Associated with the Ascochyta Blight Complex in Western Regions of Algeria

European Scientific Journal ESJ ◽

10.19044/esj.2018.v14n9p276 ◽

2018 ◽

Vol 14 (9) ◽

pp. 276

Author(s):

A. Tadja

Keyword(s):

Molecular Weight ◽

Pisum Sativum ◽

Ascochyta Blight ◽

Pathogenic Fungi ◽

Large Set ◽

Its Regions ◽

Pcr Products ◽

Ascochyta Pinodes ◽

Pathogenicity Tests ◽

Ascochyta Pisi

The study is conducted in two growing areas of garden pea (Pisum sativum L.) in northwestern Algeria. Damages caused by Ascochyta sp complex are important in particular for the variety of Kelvedon Wonder. Observations carried out on the infected plants for several years, indicate the presence of superimposed necrosis of different sizes on all aerial organs. However, these observations do not differentiate symptoms by species. The results of morphological and molecular characterization with sequencing in internal transcribed spacer (ITS) regions and inoculation tests on 32 isolates in the laboratory of symbiosis and plant pathology from Toulouse (France), show a reconciliation of the sequencing by polymerase chain reaction (PCR) products and size necrosis for all Ascochyta pinodes and pinodella. Alone, Ascochyta pisi is distinguished by a smaller size necrosis. On the molecular level, all isolates whose ITS regions were amplified by PCR, expresses similar size products (550 bp). This molecular weight is found on a large set of pathogenic fungi. The three species of Ascochyta sp complex do not exhibit polymorphism for Pisum sativum species and have an identical molecular weight. The pathogenicity tests performed showed differences in aggressiveness on the host plant. Ascochyta pinodes is the most aggressive than the other two species. As a result, it causes more damage to the crop.

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First Report of Brown Rot Caused by Monilinia fructicola on Nectarine in Serbia

Plant Disease ◽

10.1094/pdis-08-12-0718-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 147-147 ◽

Cited By ~ 9

Author(s):

J. Hrustić ◽

M. Mihajlović ◽

B. Tanović ◽

G. Delibašić ◽

I. Stanković ◽

...

Keyword(s):

Prunus Persica ◽

Its Region ◽

Fruit Rot ◽

Economic Losses ◽

Morphological Identification ◽

Single Spore ◽

Daily Growth ◽

Causal Organism ◽

First Report ◽

Apple Fruits

In August 2011, nectarine (Prunus persica (L.) Batsch var. nucipersica (Suckow) C. K. Schneid) fruit originated from Oplenac region with symptoms of fruit rot was collected at a green market in Belgrade. Fruit had large, brown, sunken lesions covered with grayish brown tufts. Symptoms resembled those caused by species of Monilinia including M. laxa, M. fructigena, or M. fructicola (2). In order to isolate the causal organism, small superficial fragments of pericarp were superficially disinfected with commercial bleach and placed on potato dextrose agar (PDA). The majority (32 out of 33) isolates formed rosetted non-sporulating colonies with lobed margins resembling those of M. laxa. However, one isolate (Npgm) produced an abundant, grayish-white colony with even margins and concentric rings of sporogenous mycelium, resembling those described for M. fructicola (2). Conidia were one-celled, hyaline, ellipsoid to lemon shaped, 7.38 to 14.76 × 4.92 to 9.84 μm, and borne in branched monilioid chains. The average daily growth on PDA at 24°C was 10.9 mm. A single-spore isolate of Npgm was identified as M. fructicola based on the morphology of colony and conidia, temperature requirements, and growth rate (2). Morphological identification was confirmed by an amplified product of 535 bp using genomic DNA extracted from the mycelium of pure culture and species-specific PCR for the detection of M. fructicola (2). The ribosomal internal transcribed spacer (ITS) region of rDNA of Npgm was amplified and sequenced using primers ITS1/ITS4. Sequence analysis of ITS region revealed 100% nucleotide identity between the isolate Npgm (GenBank Accession No. JX127303) and 17 isolates of M. fructicola from different parts of the world, including four from Europe (FJ411109, FJ411110, GU967379, JN176564). Pathogenicity of the isolate Npgm was confirmed by inoculating five surface-disinfected mature nectarine and five apple fruits by placing a mycelial plug under the wounded skin of the fruit. Nectarine and apple fruits inoculated with sterile PDA plugs served as a negative controls. After a 3-day incubation at 22°C, inoculated sites developed brown lesions and the pathogen was succesfully reisolated. There were no symptoms on the control nectarine or apple fruits. M. fructicola is commonly present in Asia, North and South America, New Zealand, and Australia, while in the EPPO Region the pathogen is listed as an A2 quarantine organism (3). In Europe, the first discovery of M. fructicola was reported in France and since then, it has been found in Hungary, Switzerland, the Czech Republic, Spain, Slovenia, Italy, Austria, Poland, Romania, Germany, and Slovakia (1). Most recently, M. fructicola was found on stored apple fruits in Serbia (4). To our knowledge, this is the first report of M. fructicola decaying peach fruit in Serbia. These findings suggest that the pathogen is spreading on its principal host plants and causing substantial economic losses in the Serbian fruit production. References: (1) R. Baker et al. European Food Safety Authority. Online publication. www.efsa.europa.eu/efsajournal . EFSA J. 9:2119, 2011. (2) M. J. Côté. Plant Dis. 88:1219, 2004. (3) OEPP/EPPO. EPPO A2 list of pests recommended for regulation as quarantine pests. Version 2009-09. http://www.eppo.org/QUARANTINE/listA2.htm . (4). M. Vasic et al. Plant Dis. 96:456, 2012.

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Subcutaneous ticks: a first report in a golden jackal, and their absence in non-canid carnivores

Parasites & Vectors ◽

10.1186/s13071-020-04510-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Noureddine Mechouk ◽

Georgiana Deak ◽

Angela Monica Ionică ◽

Dan Traian Ionescu ◽

Gabriel Bogdan Chișamera ◽

...

Keyword(s):

Ixodes Ricinus ◽

Subcutaneous Tissue ◽

Species Level ◽

The Other ◽

Morphological Identification ◽

Golden Jackal ◽

Canis Aureus ◽

First Report ◽

Host Spectrum ◽

Hematophagous Arthropods

Abstract Background Ticks are hematophagous arthropods which normally attach to the surface of the host’s skin. Their aberrant presence in the subcutaneous tissue of a few carnivores, predominantly foxes, has been reported. However, there have been no reports of this phenomenon in other carnivores such as mustelids or golden jackals. Our aim was to investigate the host spectrum for this aberrant localization of ticks. Methods Between 2015 and 2020, a total of 198 carcasses of 12 species of carnivore were examined by parasitological necropsy. When a subcutaneous tick was found, the nodule was removed, carefully dissected, and stored in ethanol. The morphological identification of the subcutaneous tick was carried out to species level. Results A single subcutaneous tick was found in one carcass, that of a golden jackal (Canis aureus). The tick was identified as a female Ixodes ricinus. All the other carcasses were negative for the presence of subcutaneous ticks. Conclusion To our knowledge, this is the first report of a subcutaneous tick in a golden jackal. This finding broadens the host spectrum of subcutaneous ticks, and reinforces the idea that, among carnivores, this phenomenon only occurs in canids.

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First Report of Ascochyta rabiei Causing Ascochyta Blight of Chickpea in Argentina

Plant Disease ◽

10.1094/pdis-02-12-0153-pdn ◽

2012 ◽

Vol 96 (9) ◽

pp. 1375-1375 ◽

Cited By ~ 3

Author(s):

G. Viotti ◽

M. A. Carmona ◽

M. Scandiani ◽

A. N. Formento ◽

A. Luque

Keyword(s):

Disease Incidence ◽

Ascochyta Blight ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

Ascochyta Rabiei ◽

Infected Leaf ◽

Buenos Aires Province ◽

Conidial Suspension ◽

First Report ◽

Plastic Bags

In November 2011, lesions similar to those reported for Ascochyta blight (1) were observed on Cicer arietinum L. (chickpea) plants growing in three commercial fields located at Río Primero and Río Segundo (Cordoba Province) and Lobería (Buenos Aires Province), Argentina. Disease incidence (percentage of plants affected) was 100% in all fields surveyed. Plants showed leaves, petioles, stems, and pods with brown lesions. Symptoms on leaves and pods were circular to oval (2 to 14 mm) while in the stems the lesions were elongated (2 to 30 mm). Seeds appeared small and shriveled with brown discoloration. Morphology of the fungi was examined on infected tissues. Numerous black pycnidia measuring 94.6 to 217.9 μm (145.9 ± 28.8 μm), arranged in concentric rings, were observed within of all the lesions. Conidia were predominantly aseptate, straight, hyaline with blunt ends, and measured 9.3 to 12.9 (11.3 ± 1.12) × 3.3 to 5.0 μm (4.2 ± 0.51). Morphological characteristics of the pathogen were similar to those described for Ascochyta rabiei (Pass.) Labrousse (teleomorph Didymella rabiei (Kovacheski) v. Arx (= Mycosphaerella rabiei Kovacheski)) (2). Fungus from infected leaf tissues was isolated on potato dextrose agar. Pathogenicity tests were conducted on seedlings of the susceptible cultivar by spraying leaves of each of 100 seedling plants with 10 ml of a conidial suspension (2 × 104 conidia/ml) of the isolated pathogen with a handheld atomizer. Plants were covered with plastic bags and placed in a growing chamber at 20 to 25°C for 3 days. The plastic bags were removed and the plants were maintained in high humidity at the same temperature. Noninoculated plants were used as controls. After 5 days, all inoculated plants showed typical symptoms. Foliar and stem lesions symptoms were similar to those originally observed in the field. Control plants remained healthy. Koch's postulates were fulfilled by isolating A. rabiei from inoculated plants. The colonies and the morphology of conidia were the same as those of the original isolates. To our knowledge, this is the first report of A. rabiei infecting chickpeas in Argentina. The outbreak of Ascochyta blight in Argentina is of concern because of its severity and the possibility that the pathogen was introduced on seed. This report underscores the need for further research on effective management programs for Ascochyta blight. References: (1) B. Bayaa and W. Chen. Compendium of Chickpea and Lentil Diseases and Pests The American Phytopathological Society, St. Paul, MN, 2011. (2) E. Punithalingam and P. Holliday. Page 337 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.

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First Report of Corynespora cassiicola Causing Leaf Spot of Cassava in China

Plant Disease ◽

10.1094/pdis-94-7-0916a ◽

2010 ◽

Vol 94 (7) ◽

pp. 916-916 ◽

Cited By ~ 1

Author(s):

X.-B. Liu ◽

T. Shi ◽

C.-P. Li ◽

J.-M. Cai ◽

G.-X. Huang

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenic Fungi ◽

Commonwealth Mycological Institute ◽

Corynespora Cassiicola ◽

Single Spore ◽

First Report ◽

Leaf Spots ◽

Main Vein

Cassava (Manihot esculenta) is an important economic crop in the tropical area of China. During a survey of diseases in July and September of 2009, leaf spots were observed on cassava plants at three separate plantations in Guangxi (Yunfu and Wuming) and Hainan (Baisha) provinces. Circular or irregular-shaped leaf spots were present on more than one-third of the plants. Spots were dark brown or had white papery centers delimited by dark brown rims and surrounded by a yellow halo. Usually, the main vein or small veinlets adjacent to the spots were dark. Some defoliation of plants was evident at the Wuming location. A fungus was isolated from symptomatic leaves from each of the three locations and designated CCCGX01, CCCGX02, and CCCHN01. Single-spore cultures of these isolates were incubated on potato dextrose agar (PDA) for 7 days with a 12-h light/dark cycle at a temperature of 28 ± 1°C. Conidiophores were straight to slightly curved, unbranched, and pale to light brown. Conidia were formed singly or in chains, obclavate to cylindrical, straight or curved, subhyaline-to-pale olivaceous brown, 19.6 to 150.3 μm long and 5.5 to 10.7 μm wide at the base, with 4 to 13 pseudosepta. Morphological characteristics of the specimen and their conidia were similar to the descriptions for Corynespora cassiicola (2). The isolate CCCGX01 was selected as a representative for molecular identification. Genomic DNA was extracted by the cetyltrimethylammoniumbromide protocol (3) from mycelia and used as a template for amplification of the internal transcribed spacer (ITS) region of rDNA with primer pair ITS1/ITS4. The sequence (GenBank Accession No. GU138988) exactly matched several sequences (e.g., GenBank Accession Nos. FJ852715, EF198117, and AY238606) of C. cassiicola (1). Young, healthy, and fully expanded green leaves of cassava cv. SC205 were surface sterilized. Ten leaves were inoculated with 10-μl drops of 104 ml suspension of conidia and five leaves were inoculated with the same volume of sterile water to serve as controls. After inoculation, leaves were placed in a dew and dark chamber for 36 h at 25°C and subsequently transferred to the light for 5 days. All inoculated leaves with isolates showed symptoms similar to those observed in natural conditions, whereas the controls remained symptom free. The morphological characteristics of reisolated conidia that formed on the diseased parts were identical with the nature isolates. To our knowledge, this is the first report of leaf spot caused by C. cassiicola on cassava in China. References: (1) L. J. Dixon et al. Phytopathology 99:1015, 2009. (2) M. B. Ellis et al. Corynespora cassiicola. No. 303 in: CMI Description of Pathogenic Fungi and Bacteria. Commonwealth Mycological Institute, Kew, UK 1971. (3) J. R. Xu et al. Genetics 143:175, 1996.

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First Report of Crown Rot of Banana Caused by Fusarium porliferatum in Georgia, USA

Plant Disease ◽

10.1094/pdis-08-21-1809-pdn ◽

2021 ◽

Author(s):

Sumyya Waliullah ◽

Greg E. Fonsah ◽

Jason Brock ◽

Yonggang Li ◽

Emran Ali

Keyword(s):

Sequence Similarity ◽

Morphological Characteristics ◽

Fusarium Proliferatum ◽

Crown Rot ◽

Post Inoculation ◽

Conidial Suspension ◽

Banana Fruit ◽

Single Spore ◽

First Report ◽

Initial Symptoms

Crown rot is one of the most damaging disease of banana fruit characterized by rot and necrosis of crown tissues. In severe cases, the disease can spread to the pedicel and banana pulp. Crown rot can be infected by several common fungi, including Lasiodiplodia theobromae, Musicillium theobromae, Colletotrichum musae, and a complex of Fusarium spp. and lead to softening and blackening of tissues (Lassois et al., 2010; Kamel et al., 2016; Triest et al., 2016; Snowdon, 1990). In November 2020, typical crown rot of banana fruits (cv. Pisang Awak, belonging to the tetraploid AABB genome) were observed from UGA Banana Research 12 Plots, Tifton, GA, with incidence rates of 15%. Initial symptoms appeared in the infected crown of green banana fruits. As the infection progressed, the crown tissues became blackened and softened, followed by an internal development of infection affecting the peduncle and the fruit, triggered early ripening of bananas. At last, the development of necrosis on the pedicels and fruits appeared and caused the fingers to fall off. To identify the pathogen, tissue pieces (~0.25 cm2) from the infected crown and pedicles were surface-sterilized in a 10% bleach solution for 1 min, followed by 30 s in 70% EtOH. The disinfected tissues were rinsed in sterile water 3 times and cultured on potato dextrose agar (PDA) amended with 50 µg/ml streptomycin at 25°C in the dark for 5–10 days. Isolates of the pathogen were purified using the single-spore isolation method (Leslie and Summerell 2006). Colonies on PDA produced fluffy aerial mycelium and developed an intense purple pigment when viewed from the underside. A range of colony pigmentation and growth rates were observed among the isolates. The microconidia were ovoid, hyaline, or ellipse in shape. The morphological features of the isolates were identified as Fusarium proliferatum (Leslie and Summerell, 2006). To further identify the isolates, genomic DNA was extracted from a representative isolate. And the internal transcribed spacer (ITS) region, the partial elongation factor (TEF1-α) gene and the β-tubulin gene (TUB2)were amplified and sequenced using the primers ITS1/ITS4 (Yin et al. 2012), EF-1 /EF-2 (O’Donnell et al. 1998) and B-tub1 /B-tub2 (O’Donnell and Cigelnik, 1997), respectively. The amplicons were sequenced and deposited in NCBI (accessions no. MZ292989, MZ293071 for ITS: MZ346602, MZ346603 for TEF1-α and MZ346600 and MZ346601 for B-tub). The ITS, TEF1-α, and B-tub sequences of the isolates showed 100% sequence similarity with Fusarium proliferatum isolates (accessions no. MT560212, LS42312, and LT575130, respectively) using BLASTn in Genbank. For pathogenicity testing, three whole bunched bananas sterilized with 10% bleach solutions and washed by sterilized water, were cut into 5 bananas per brunch. The cut surface of the banana crown was inoculated with conidial suspension (1.0 × 107 cfu/ml) of the pathogen with pipette tips. Equal number of bananas were treated with sterilized water in the same volume as a control. All bananas were sealed in a plastic bag and incubated at 25°C. After 7 days post inoculation, all inoculated bananas showed initial crown rot symptoms while no symptoms were observed on the control bananas. The fungus was re-isolated from the symptomatic tissues of infected bananas and confirmed to be genetically identical to F. proliferatum of the original inoculated strains according to morphological characteristics and molecular identification, fulfilling Koch’s postulates. To the best of our knowledge, this is the first report of F. proliferatum causing crown rot on bananas in Georgia, USA.

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First Report of Tan Spot of Wheat Caused by Pyrenophora tritici-repentis in the Pacific Northwest

Plant Disease ◽

10.1094/pdis.2003.87.2.203b ◽

2003 ◽

Vol 87 (2) ◽

pp. 203-203

Author(s):

T. L. Peever ◽

T. D. Murray

Keyword(s):

New York ◽

Pacific Northwest ◽

Sequence Similarity ◽

Triticum Aestivum L ◽

Tan Spot ◽

Morphological Description ◽

Morphological Identification ◽

First Report ◽

Pyrenophora Tritici Repentis ◽

The Pacific

In late May 2001, lesions resembling tan spot were observed on lower leaves of winter wheat (Triticum aestivum L.) in early boot stage in Nez Perce County, ID. Abundant sporulation was observed from tan lesions with chlorotic haloes after 2 days incubation in a moist chamber at room temperature. Conidia were multicelled, straw colored, approximately 100 × 15 µm, rounded at the apex, and borne singly on dark brown conidiophores. The fungus fit the morphological description of Drechslera tritici-repentis (Died.) Shoemaker, the anamorphic state of Pyrenophora tritici-repentis (Died.) Drechs. (2). Three single-conidial isolates were sampled from infected plants in a 5 × 1 m area of the affected field and induced to sporulate. Two of the isolates were used to spray-inoculate 3-week-old susceptible wheat (cv. Madsen) in the greenhouse (one plant per isolate, 1 × 105 conidia/ml), and tan spot lesions were apparent 3 to 5 days after inoculation with both isolates. DNA was extracted from all three isolates, and the entire nuclear ribosomal internal transcribed spacer (ITS) was amplified with ITS1 and ITS4 primers (4). Similarly, 610 bp of the 5′ end of the glyceraldehyde-3-phosphate-dehydrogenase gene (gpd) was amplified with gpd-1 and gpd-2 primers (1). ITS and gpd amplicons were direct-sequenced on both strands, and alignment revealed that all three isolates were identical for both regions. A BLAST search of the NCBI database with the ITS sequence revealed P. tritici-repentis accessions AY004808 and AF071348 and D. tritici-repentis accession AF163060 as the closest matches with 100, 99.8, and 98.8% sequence similarity, respectively. A similar search with the gpd sequence revealed P. tritici-repentis accessions AY004838 and AF081370 and P. bromi accession AY004839 as the closest matches with 100, 100, and 99.0% sequence similarity, respectively. These results, coupled with the morphological identification and inoculation results, confirm the identity of the fungus as P. tritici-repentis. Although reported on other grass hosts in the region (3), to our knowledge, this is the first report of tan spot of wheat in the Pacific Northwest. This disease has been of little concern to wheat producers in the Pacific Northwest due to low rainfall and relative humidity during the growing season. References: (1) M. L. Berbee et al. Mycologia 91:964, 1999. (2) M. B. Ellis, Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK. 1971. (3) R. Sprague. Diseases of Cereals and Grasses in North America (Fungi, Except Smuts and Rusts). Ronald Press Co. New York, 1950. (4) T. J. White et al. Pages 315–322 in: PCR Protocols: A Guide to Methods and Applications. Academic Press Inc., New York, 1990.

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