scholarly journals Identification of Pyrenophora teres f. maculata, Causal Agent of Spot Type Net Blotch of Barley in North Dakota

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 480-480 ◽  
Author(s):  
Z. H. Liu ◽  
T. L. Friesen
Keyword(s):  
North Dakota ◽  
Leaf Tissue ◽  
Causal Agent ◽  
Tan Spot ◽  
Pathogenicity Test ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Hordeum Vulgare L ◽  
Single Spore ◽  
Spot Type

Net blotch of barley (Hordeum vulgare L.) caused by the fungus Pyrenophora teres (anamorph Drechslera teres) is found in two forms, net form net blotch (NFNB) and spot form net blotch (SFNB). When inoculated on susceptible varieties, P. teres f. teres produces lesions with a characteristic net-like pattern surrounded by necrosis or chlorosis (NFNB), whereas P. teres f. maculata produces lesions consisting of spots surrounded by necrosis or chlorosis (SFNB). Recently, epidemics of SFNB have occurred throughout the world (4). Currently, net blotch is a significant foliar disease of barley in the North Dakota-Northwestern Minnesota agricultural region, a leading barley-production area. Diseased barley leaf tissue was collected annually from 2004 to 2008 in Fargo and Langdon, ND. Diseased leaves were incubated to promote sporulation. Ten single-spore isolates of P. teres collected from each location each year were tested for virulence by inoculation on 20 commonly used barley net blotch differential lines. Among the 100 isolates collected, one isolate collected in Fargo in 2006 (FGOH06Pt-8) and one isolate collected in Langdon in 2008 (LDNH08Pt-4) were identified as P. teres f. maculata due to their induction of spot-type lesions across the differential set. Conidial morphology of the two isolates was similar to P. teres f. teres isolates. A pathogenicity test of all isolates was performed on regional barley cvs. Tradition, Robust, and Lacey as well as barley lines Rika and Kombar (1) as previously described (3). The net form isolate 0-1 and spot form isolate DEN2.6 (obtained from B. Steffenson, University of Minnesota) were used as controls. The P. teres f. teres isolate 0-1 produced typical net type symptoms on all barley lines except the resistant line Rika, in which only small, dark spots were observed. DEN2.6 produced pin-point spot-like lesions with an extensive yellow halo on Robust, Lacey, Rika, and Kombar, but without chlorosis on Tradition. The two newly identified isolates induced elliptical spot-type lesions measuring 3 × 6 mm, larger than those produced by P. teres f. maculata isolate DEN 2.6, suggesting a higher level of virulence. We constructed a neighbor-joining phylogenetic tree using ClustalW2 ( http://www.ebi.ac.uk/ ) based on sequence identity of the internal transcribed spacer (ITS) region from 0-1 (GenBank No. GU014819), DEN2.6 (GenBank No. GU014820), FGOH06Pt-8 (GenBank No. GU014821), and LDNH08Pt-4 (GenBank No. GU014822) as well as P. teres f. maculata, P. teres f. teres, and P. tritici-repentis (causal agent of tan spot of wheat) accessions obtained from GenBank (2). All P. teres isolates clustered together and were clearly separated from the P. tritici-repentis cluster. Isolates FGOH06Pt-8 and LDNH08Pt-4 had identical ITS sequences and differed from DEN2.6 by only a single nucleotide. To our knowledge, this is the first report of P. teres f. maculata in North Dakota. Resistance to SFNB should now be considered in local barley breeding programs and cultivar releases. Reference: (1) M. Abu Qamar. Theor. Appl. Genet. 117:1261, 2008. (2) R. M. Andrie et al. Fungal Genet. Biol. 45:363, 2008. (3) Z. Lai et al. Fungal Genet. Biol. 44:323, 2007. (4) M. S. McLean et al. Crop Pasture Sci. 60:303, 2009.

scholarly journals First Report of Spot Form Net Blotch Caused by Pyrenophora teres f. maculata on Barley in the Mon-Dak Area of the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 143-143 ◽  
Author(s):  
R. T. Lartey ◽  
T. C. Caesar-TonThat ◽  
A. J. Caesar ◽  
U. M. Sainju ◽  
R. G. Evans
Keyword(s):  
North Dakota ◽  
Its Region ◽  
The United States ◽  
Northern Great Plains ◽  
Pathogenicity Test ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Morphological Examination ◽  
First Report ◽  
Barley Cultivars

Pyrenophora teres Drechs. causes net blotch of barley, a common foliar disease in cultivation zones around the world. The disease occurs in two forms, namely a net form net blotch (NFNB) caused by P. teres f. teres and a spot form net blotch (SFNB) caused by P. teres f. maculata. As in other parts of the northern Great Plains, in the Mon-Dak area (western North Dakota and eastern Montana), NFNB is prevalent. SFNB was first reported in western Montana in 1983 (1) and more recently in eastern North Dakota in 2010 (3) but not in the Mon-Dak area. In the summer of 2011, unusual spot lesions that were surrounded by necrosis or chlorosis were observed on different barley cultivars in fields at Williston, ND, Nesson Valley, ND, and Sidney, MT areas. Diseased leaves from various barley cvs. from the three locations were transferred to water agar and incubated at room temperature for 24 h to induce sporulation. Morphological examination of conidia (45 to 169 × 15 to 21 μm) did not show significant differences from a known isolate of P. teres f. teres 0-1 (provided by Tim Friesen, ARS, Fargo, ND). For pathogenicity testing, six 14-day-old plants of barley cv. Tradition were sprayed until runoff with a 2,000 spore/ml suspension of two isolates from each location and the control P. teres f. maculata isolate DEN2.6 (provided by Tim Friesen). Plants were incubated first in a lighted humidity chamber for 24 h and then in a greenhouse for 7 days at 21°C. Regardless of inoculum source, spot lesions surrounded by necrosis or chlorosis, typical of SFNB, appeared on the inoculated leaves within 7 days. Fungi isolated from symptomatic leaves were identified as P. teres and the morphology of the conidia was undistinguishable from those of P. teres f. teres. All control plants which were sprayed with sterile distilled water were symptomless. The pathogenicity test was repeated. Rapid PCR detection and amplicon sequencing (2) of the internal transcribed spacer (ITS) region of ribosomal genes was performed on field and pathogenicity test leaf lesion samples to confirm the presence of P. teres f. maculata. DNA templates were prepared using the Extract-N-Amp Plant PCR Kits (Sigma Chemical Co., St. Louis, MO) and subjected to PCR using ITS1 and ITS4 primers. Amplicons were then purified and sequenced. The 585-bp nucleotide sequences of P. teres f. maculata from Mon-Dak area were submitted to GenBank under accession nos. PtmNES1 (JX187587), PtmSDY1 (JX187588), PtmSDY2 (JX187589), and PtmWIL1 (JX187590). The sequences from the four locations shared 100% similarity and also with P. teres f. maculata (EF452471) from GenBank while showing 10 nucleotide differences (99% similarity) with P. teres f. teres (EF452472).The results represent first report of SFNB in the Mon-Dak. Barley is one of the most important crops in the area. Resistance of the NFNB and SFNB of barley are controlled by different genes (4). Based on this report, SFNB therefore have to be considered in selection of barley cultivars for cultivation in the area. References: (1) H. E Bockelman et al. Plant Dis. 67:696, 1983. (2) R. T. Lartey et al. J. Sugar Beet Res. 40:1, 2003. (3) Z. H. Liu and T. L. Friesen. Plant Dis. 94:480, 2010. (4) O. M. Manninen et al. Genome. 46:1564, 2006.

scholarly journals First Report of Spot Type of Barley Net Blotch Caused by Pyrenophora teres f. sp. maculata in Uruguay

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1162-1162
Author(s):  
S. A. Pereyra ◽  
S. E. Germán
Keyword(s):  
North Dakota ◽  
Tween 20 ◽  
Pyrenophora Teres ◽  
Sterile Water ◽  
Net Blotch ◽  
First Report ◽  
Production Region ◽  
Resistant Infection ◽  
Infection Types ◽  
Spot Type

In September 2003, leaves exhibiting spot-type lesions similar to those produced by Cochliobolus sativus Drechs. ex Dastur were widely observed in six commercial barley crops of cvs. Norteña Daymán, Norteña Carumbé, and MUSA 936 in Soriano and Río Negro provinces, the main barley production region in western Uruguay. Spot lesions were tan to dark brown, circular to elliptical, and 3 to 10 mm in diameter. Larger lesions were surrounded by a chlorotic margin of varying width. Affected leaf pieces (10 to 15) from each field were placed in a moist chamber for 2 days to promote sporulation. A fungus identified morphologically as Pyrenophora teres (Died.) Drechs. (1) was consistently isolated from infected leaves. However, symptoms did not correspond to the net-type lesions of net blotch commonly produced by P. teres f. sp. teres in Uruguay. Three monoconidial cultures were obtained by transferring single conidia to potato dextrose agar and then to 10% V8 juice agar and incubated at 20 to 22°C with a 12-h photoperiod for 10 days. Adding sterile water to each plate and gently rubbing the surface with a microscope slide prepared inoculum for pathogenicity tests. Conidia concentration was adjusted to 1 × 104 conidia per ml. Sixty-eight barley genotypes from Uruguay, ICARDA/CIMMYT, and North Dakota were grown in the greenhouse for 2 weeks at 20 to 22°C with a 14-h photoperiod. For each monoconidial isolate, three seedlings of each genotype were inoculated at the three-leaf stage 15 to 16 days after seeding with 0.4 ml of the inoculum suspension with an airbrush inoculator. A drop of Tween 20 was added per 40 ml of inoculum suspension. One set of each genotype was inoculated with sterile water as a control. Seedlings were placed in a dew chamber at 20°C and 100% relative humidity in the dark for 24 h and then returned to prior conditions. The first lesions developed after 7 to 9 days. Leaves two and three of the plants were visually rated for disease (3) 13 days after inoculation. Control plants were disease free. The most susceptible reactions were observed on cvs. Norteña Daymán, MUSA 936, and line CLE 230 (Uruguay). Symptoms were similar in shape and size to those observed in the fields. The most resistant infection types were observed on several Uruguayan and North Dakota advanced lines. The fungus was consistently reisolated from inoculated plants. On the basis of morphology and symptoms produced, the pathogen was identified (2) as P. teres. f. sp. maculata Smedeg. To our knowledge, this is the first report of this fungus causing spot-like symptoms of net blotch in Uruguay. References: (1) M. B. Ellis. Dematiaceous hyphomycetes, CABI, Oxon, UK, 1971. (2) V. Smedergaard-Petersen. Pages 124–144 in: R. Vet. Agr. Univ. Yearbook, Copenhagen, 1971. (3) A. Tekauz. Can. J. Plant Pathol.7:181, 1985.

scholarly journals First Report of Colletotrichum boninense Causing Anthracnose on Pepper in China

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 138-138 ◽  
Author(s):  
Y. Z. Diao ◽  
J. R. Fan ◽  
Z. W. Wang ◽  
X. L. Liu
Keyword(s):  
Internal Transcribed Spacer ◽  
Severe Disease ◽  
Causal Agent ◽  
Its Sequences ◽  
Universal Primers ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report ◽  
Species Specific

Anthracnose, caused by Colletotrichum spp., is a severe disease and results in large losses in pepper (Capsicum frutescens) production in China (4). Colletotrichum boninense is one of the Colletotrichum species in pepper in China. In August 2011, anthracnose symptoms (circular, sunken lesions with orange to black spore masses) were observed on pepper fruits in De-Yang, Sichuan Province, China. Three single-spore isolates (SC-6-1, SC-6-2, SC-6-3) were obtained from the infected fruits. A 5-mm diameter plug was transferred to potato dextrose agar (PDA); the isolates formed colonies with white margins and circular, dull orange centers. The conidia were cylindrical, obtuse at both ends, and 10.5 to 12.6 × 4.1 to 5.0 μm. The colonies grew rapidly at 25 to 28°C, and the average colony diameter was 51 to 52 mm after 5 days on PDA at 25°C. Based upon these characters, the causal agent was identified as C. boninense. To confirm the identity of the isolates, the internal transcribed spacer (ITS) regions were amplified with the ITS1/ITS4 universal primers (1). The internal transcribed spacer (ITS) sequences (Accession No. JQ926743) of the causal fungus shared 99 to 100% homology with ITS sequences of C. boninense in GenBank (Accession Nos. FN566865 and EU822801). The identity of the causal agent as C. boninense was also confirmed by species-specific primers (Col1/ITS4) (2). In a pathogenicity test, five detached ripe pepper fruits were inoculated with 1 μl of a conidial suspension (106 conidia/mL) or five fruits with 1 μl of sterile water were kept as control. After 7 days in a moist chamber at 25°C, typical anthracnose symptoms had developed on the five inoculated fruits but not on control fruits. C. boninense was reisolated from the lesions, and which was confirmed by morphology and molecular methods as before. There have reports of C. boninense infecting many species of plants, including pepper (3). To our knowledge, this is the first report of C. boninense causing anthracnose on pepper in China. References: (1) A. K. Lucia et al. Phytopathology 93:581, 2002. (2) S. A. Pileggi et al. Can. J. Microbiol. 55:1081, 2009. (3) H. J. Tozze et al. Plant Dis. 93:106, 2009. (4) M. L. Zhang. J. Anhui Agri. Sci. 2:21, 2000.

SOURCES OF RESISTANCE IN BARLEY TO PYRENOPHORA TERES

1965 ◽  
Vol 45 (2) ◽  
pp. 189-193 ◽  
Author(s):  
K. W. Buchannon ◽  
W. C. McDonald
Keyword(s):  
North Dakota ◽  
Quality Characteristics ◽  
Seedling Stage ◽  
Malting Quality ◽  
Western Canada ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Sources Of Resistance ◽  
Highly Pathogenic ◽  
Resistant Varieties

The reaction to infection by Pyrenophora teres Drechs., the incitant of net blotch of barley, was determined for 6,174 varieties in the U.S.D.A. World Barley Collection. Forty varieties, seventeen of them from Ethiopia, were resistant in the seedling stage to a highly pathogenic strain of the fungus prevalent in Western Canada and to composites of isolates from Manitoba, Saskatchewan, Alberta, Ontario, North Dakota, California, and Mexico. They were also resistant in the field at three locations in Western Canada. Agronomic and malting quality characteristics for the resistant varieties were also recorded.

NEW TYPES OF VIRULENCE IN PYRENOPHORA TERES IN CANADA

1974 ◽  
Vol 54 (4) ◽  
pp. 731-734 ◽  
Author(s):  
A. TEKAUZ ◽  
J. T. MILLS
Keyword(s):  
Hordeum Vulgare ◽  
Spot Blotch ◽  
Cochliobolus Sativus ◽  
Pyrenophora Teres ◽  
Hordeum Vulgare L ◽  
Moderately Resistant ◽  
Hybrid Lines ◽  
Spot Type

Isolates of Pyrenophora teres (Died.) Drechsl. causing either net- or spot-type symptoms on barley (Hordeum vulgare L.) were collected in 1973 from fields near Winnipeg, Manitoba. Spot-type symptoms were similar to those of spot blotch incited by Cochliobolus sativus (Ito and Kurib.) Drechsl. ex Dastur. The cultivars Herta and Fergus, previously reported to be moderately resistant, were susceptible to both types of isolates. These two cultivars presently account for virtually all of the two-rowed barley and about half of the total barley acreage in Manitoba. The resistant hybrid lines CI 5791 and BT 201 retained their resistance to the isolates which produced net-type symptoms but were less resistant to those producing the spot type.

COMPARISON OF THE EFFECTS OF NET BLOTCH AND LEAF REMOVAL ON YIELD IN BARLEY

1969 ◽  
Vol 49 (6) ◽  
pp. 731-735 ◽  
Author(s):  
L. Piening ◽  
M. L. Kaufmann
Keyword(s):  
Leaf Tissue ◽  
Causal Agent ◽  
Low Fertility ◽  
Leaf Removal ◽  
Net Blotch ◽  
Yield Losses ◽  
Leaf Clipping ◽  
Drechslera Teres ◽  
Time Required

Experiments were conducted in a growth cabinet to compare yield losses in barley caused by partial defoliation and foliar infection by Drechslera teres, the causal agent of net blotch. When Gateway barley was grown under a low fertilizer regime, infection of lower leaves caused greater yield reductions than the removal of comparable leaves. In contrast, infection or removal of upper leaves reduced yields to about the same extent. Under a higher fertilizer regime, yield reductions from infection or defoliation were about equal (14%). These losses were considerably lower than those from plants on the low fertility regime and were similar to those caused by net blotch in the field.In leaf clipping experiments, root weights and yields were reduced proportionately to the amount of leaf tissue removed. The time required to head was also increased with increasing amounts of leaf clipping.

scholarly journals Mapping and validation of the genes for resistance to Pyrenophora teres f. teres in barley (Hordeum vulgare L.)

2003 ◽  
Vol 54 (12) ◽  
pp. 1369 ◽  
Author(s):  
M. Cakir ◽  
S. Gupta ◽  
G. J. Platz ◽  
G. A. Ablett ◽  
R. Loughman ◽  
...  
Keyword(s):  
Natural Infection ◽  
Adult Plant ◽  
Research Station ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Hordeum Vulgare L ◽  
Breeding Programs ◽  
Barley Breeding ◽  
Software Packages ◽  
Selection Of

Identification and deployment of disease resistance genes are key objectives of Australian barley breeding programs. Two doubled haploid (DH) populations derived from Tallon × Kaputar (TK) and VB9524 × ND11231 (VN) crosses were used to identify markers for net type net blotch (NTNB) (Pyrenophora teres f. teres). The maps included 263 and 250 markers for TK and VN populations, respectively. The TK population was screened with 5 pathotypes and the VN population with 1 pathotype of NTNB as seedlings in the glasshouse. In addition, the TK population was subjected to natural infection in the field at Hermitage Research Station, Qld. Analyses of the markers were performed using the software packages MapManager and Qgene. One region on chromosome 6H was strongly associated with resistance to NTNB in both populations (R2 = 83% for TK and 66% for VN). In the TK population, 2 more quantitative trait loci (QTLs) were identified on chromosomes 2H and 3H, with R2 values of 30% and 31%, respectively. These associations were consistent over all pathotypes studied during the seedling stage. The same QTL on chromosome 6H was also found to be highly significantly associated (R2 = 65%) with the adult plant (field) response in the TK population. There are several very closely linked markers showing strong associations in these regions. Association of the 4 markers on chromosome 6H QTL with resistance to the NTNB has been validated in 2 other DH populations derived from barley crosses Pompadour × Stirling and WPG8412 × Stirling. These markers present an opportunity for marker assisted selection of lines resistant to NTNB in barley breeding programs.

Genetic studies on net blotch resistance in a barley cross

1996 ◽  
Vol 76 (4) ◽  
pp. 715-719 ◽  
Author(s):  
K.M. Ho ◽  
T.M. Choo ◽  
A. Tekauz ◽  
R.A. Martin
Keyword(s):  
Hordeum Vulgare ◽  
Dominant Gene ◽  
Recessive Gene ◽  
Pyrenophora Teres ◽  
Chromosome 2 ◽  
Net Blotch ◽  
Hordeum Vulgare L ◽  
Key Words Barley ◽  
Recessive Genes ◽  
Selection For

An investigation was initiated to study the genetics of resistance to three isolates of Pyrenophora teres (WRS102, WRS858, and WRS857), which have been routinely used for screening for net blotch resistance in Canada. The F1, F2, and doubled-haploid lines were derived from a Leger/CI9831 cross of barley (Hordeum vulgare L.). These materials, along with their parents, were inoculated with each of the three isolates at the three-leaf stage in growth chambers. Results showed that resistance to WRS102 was controlled by three recessive genes, resistance to WRS858 by one recessive gene, and resistance to WRS857 by either one dominant gene or two complementary genes. One of the WRS102-resistance genes appeared to be on chromosome 2 and another linked to the WRS858-resistance gene. Resistance to these three isolates was not associated with awn type, esterase 1, and esterase 5. Selection for resistance to WRS102 and WRS858 would be more effective than selection for resistance to WRS857 in a conventional breeding program. Key words: Barley, Hordeum vulgare, net blotch, Pyrenophora teres, haploids

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