Generation and utilization of chemical-resistant mutants in Pyrenophora tritici-repentis, the causal agent of tan spot of wheat

Tan spot, caused by the fungal pathogen Pyrenophora tritici-repentis, is a major leaf spot disease of wheat worldwide. To facilitate genetic analysis of this homothallic fungus, mutants resistant to the fungicide iprodione or hygromycin B were created through ultraviolet light mutagenesis and used in sexual crosses. Conidia from two isolates of P. tritici-repentis, sensitive to both chemicals (iprodione-S hygromycin-S), were exposed to ultraviolet light to obtain four mutants resistant to iprodione but sensitive to hygromycin B (iprodione-R hygromycin-S) and three mutants resistant to hygromycin B but sensitive to iprodione (iprodione-S hygromycin-R). The mutants were paired in all combinations, and the markers allowed crossed progeny to be distinguished from selfed progeny. Crossed ascospore progeny from pairings between iprodione-R hygromycin-S isolates and iprodione-S hygromycin-R isolates and between iprodione-R hygromycin-R isolates and iprodione-S hygromycin-S segregated 1:1 for resistance–sensitivity to both iprodione and hygromycin B. These results indicate that one locus controls iprodione resistance and a second independent locus controls hygromycin B resistance. This study should facilitate further genetic research on the tan spot fungus by providing a simple marker system. Key words: genetics, inheritance, Drechslera, yellow spot, leaf spot.

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Identification of a major QTL for yellow leaf spot resistance in the wheat varieties Brookton and Cranbrook

Australian Journal of Agricultural Research ◽

10.1071/ar03140 ◽

2004 ◽

Vol 55 (3) ◽

pp. 315 ◽

Cited By ~ 35

Author(s):

J. Cheong ◽

H. Wallwork ◽

K. J. Williams

Keyword(s):

Microsatellite Markers ◽

Leaf Spot ◽

Bulked Segregant Analysis ◽

Tan Spot ◽

Resistance Locus ◽

Yellow Leaf ◽

Wheat Varieties ◽

Seedling Resistance ◽

Pyrenophora Tritici Repentis ◽

Chromosome 5B

Yellow leaf spot (YLS) or tan spot, caused by Pyrenophora tritici-repentis, is a major foliar disease of wheat. A bioassay was used to identify YLS seedling resistance phenotypes of Krichauff/Brookton and Cranbrook/Halberd doubled-haploid (DH) populations. Bulked-segregant analysis was used to identify amplified fragment length polymorphism (AFLP) markers linked to a YLS resistance locus in the wheat cultivar Brookton. Three AFLPs were linked to YLS resistance and also to each other. One of these AFLPs was mapped to the interval Xbcd351–Xcdo400, which has been assigned to chromosome 5BL. Microsatellite markers in this region were selected from several maps and were genotyped on the Krichauff/Brookton population. Together with the bulked segregant analysis (BSA)-derived AFLPs, the microsatellite markers explained up to 39% of the total phenotypic variation (logarithm of odds ratio, LOD ≥� 7.32), confirming the chromosome 5BL assignment of a Brookton YLS resistance locus, at or near the previously identified Pyrenophora tritici-repentis toxin-insensitivity locus tsn1. The marker–trait linkage was validated in the Cranbrook/Halberd DH population, in which the same microsatellite markers explained up to 60% of the total trait variance for YLS. The markers identified can be used for the selection of the Brookton and Cranbrook YLS seedling resistance locus on chromosome 5B.

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The epidemiology of leaf spot disease in a native prairie. II. Airborne spore populations of Pyrenophora tritici-repentis

Canadian Journal of Botany ◽

10.1139/b75-260 ◽

1975 ◽

Vol 53 (20) ◽

pp. 2345-2353 ◽

Cited By ~ 30

Author(s):

R. A. A. Morrall ◽

R. J. Howard

Keyword(s):

Wind Speed ◽

Leaf Spot ◽

Diurnal Periodicity ◽

Leaf Spot Disease ◽

Spore Dispersal ◽

Spot Disease ◽

Native Prairie ◽

Pyrenophora Tritici Repentis ◽

Daily Total

A Burkard 7-day volumetric spore sampler was operated continuously from April 14 to November 23, 1970, and from April 21 to September 29, 1971, at Matador, Saskatchewan, in a native prairie dominated by Agropyron dasystachyum and A. smithii. Both ascospores and conidia of Pyrenophora tritici-repentis were trapped, but the counts of conidia greatly exceeded those of ascospores. The peak catch of ascospores occurred before that of conidia in both years. The total numbers of conidia per month were similar in both years except in June, when six times as many were trapped in 1971 as in 1970. Most conidia and ascospores are believed to have originated on dead infected grasses since P. tritici-repentis was shown not to sporulate on lesions on live Agropyron leaves. There was a marked diurnal periodicity in the trapping of conidia, with the peak usually at about 1200 h. This periodicity probably reflected the effects of light on sporulation and of wind speed on spore dispersal. However, simple meteorological explanations could not be found for the wide fluctuations (0–707) that occurred in the daily total catches of conidia during the midsummer period.

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Effects of crop rotations and fertilizer management on leaf spotting diseases of spring wheat in southwestern Saskatchewan

Canadian Journal of Plant Science ◽

10.4141/p97-082 ◽

1998 ◽

Vol 78 (3) ◽

pp. 489-496 ◽

Cited By ~ 32

Author(s):

M. R. Fernandez ◽

R. P. Zentner ◽

B. G. McConkey ◽

C. A. Campbell

Keyword(s):

Spring Wheat ◽

Leaf Spot ◽

Leaf Tissue ◽

Triticum Aestivum L ◽

Fertilizer Application ◽

Tan Spot ◽

P Deficiency ◽

Pyrenophora Tritici Repentis ◽

Leaf Spots ◽

Phaeosphaeria Nodorum

The objective of this study was to determine the effect of crop sequence, summerfallow frequency, and fertilizer application, on the severity of leaf spotting diseases of spring wheat (Triticum aestivum L.). In the field experiment examined, Pyrenophora tritici-repentis (Died.) Drechs. was the pathogen most commonly isolated from lesioned leaf tissue, followed by stagonospora blotch (Phaeosphaeria nodorum [E. Müller] Hedjaroude). The severity of leaf spots in wheat after fallow was greater than in monoculture continuous wheat, or in wheat after a noncereal crop. Percent area with leaf spots in wheat grown after wheat was higher than in wheat grown after flax (Linum usitatissimum L.) or lentil (Lens culinaris Medikus) in years with high disease pressure (1995 and 1996), but not in 1993 or 1994 when overall disease levels were low. Under soil N-deficient conditions, leaf spot levels increased in years with dry summers (1994 and 1996), whereas a P deficiency decreased leaf spot severity in years that had cool and wet springs (1995 and 1996). A survey of producers' fields confirmed the observations made in the research plots, in particular, wheat after wheat was not more severely diseased than wheat grown in rotation with a noncereal crop. We concluded that the use of fallow, or 1 yr of rotation with a noncereal crop, will not reduce leaf spotting diseases of spring wheat in southwestern Saskatchewan. The best rotation aimed at reducing the levels of disease appeared to be 2 consecutive years of spring wheat, followed by at least 2 yr of a noncereal crop, or by a noncereal crop and summerfallow. Key words: Leaf spot, tan spot, Pyrenophora tritici-repentis, stagonospora blotch, Phaeosphaeria nodorum, septoria blotch, Mycosphaerella graminicola, crop rotation, tillage, fertility

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Yellow leaf spot of winter bread wheat in the Saratov region

Grain Economy of Russia ◽

10.31367/2079-8725-2020-69-3-67-71 ◽

2020 ◽

pp. 67-71

Author(s):

E. A. Konkova ◽

S. V. Lyashcheva

Keyword(s):

Bread Wheat ◽

Causative Agent ◽

Leaf Spot ◽

Wheat Variety ◽

Tan Spot ◽

Soft Wheat ◽

Yellow Leaf ◽

Saratov Region ◽

Pyrenophora Tritici Repentis ◽

Winter Bread Wheat

The purpose of the current work was to study the development of tan spot, the causative agent of yellow leaf spot Pyrenophora tritici-repentis (Died) Drechsler on winter bread wheat in the conditions of the Saratov region of Russia. In 2018–2019 there was carried out an estimation of the resistance of 33 winter bread wheat samples to the causative agent of yellow leaf spot. It was established that the varieties “Gostianum 237” and “Levoberezhnaya 1” were characterized by a high level of resistance in the fields. There were identified such weak susceptible varieties as “Victoria 95”, “Gubernia”, “Mironovskaya 808”, “Donskaya bezostaya”, “Smuglyanka”, “Kalach 60”, “111-96 / Zhemchuzhina Povolzhiya”, “L 329 / Urozhaynaya”, “Gubernia / Zhemchuzhina Povolzhiya”, “Saratovskaya 90/ Ukraina”, “L 503 / M Freeman”, “81-93 / (Saratovskaya 11 / Kharkov 82)”. There was identified a moderate damage in the varieties “Lutenscens 230”, “Saratovskaya 80”, “Saratovskaya 90 / 14431 M”, “Sozvesdie”, “Anastasia”, “Saratovskaya 8 / Yubilyar”. The varieties “Zhemchuzhina Povolzhiya”, “Saratovskaya 17”, “Elvira”, “Saratovskaya 8 / B.Z.D.”, “(26-72 / N 49)/(L 15 / Pia)/Sar. 8)”, “Saratovskaya 8 / Yubilyar”, “L 503 / M Freeman”, “30-99/(Saratovskaya 11 / Kharkovskaya 82)”, “Sharada / L 31-98”, “346-06 / L 1334-5”, “Saratovskaya 90”, “L 329 / Saratovskaya ubileynaya”, “Istok/(Saratovskaya 90 / L 503)”, “Brigantina / Don 74” were found susceptible to the pathogen. It was identified that the proportion of winter soft wheat samples resistant to Pyrenophora tritici-repentis was 42% of the total number of varieties studied. There was studied dynamics of Pyrenophora tritici-repentis development in the winter soft wheat variety “Saratovskaya90”. It was found out that the damage degree of the winter bread wheat variety “Saratovskaya90” greatly depended upon the remoteness of the sowings from the source of infection.

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Races of Pyrenophora tritici-repentis in the Czech Republic

Acta Agrobotanica ◽

10.5586/aa.2005.011 ◽

2012 ◽

Vol 58 (1) ◽

pp. 73-78 ◽

Cited By ~ 2

Author(s):

J. Šárová ◽

A. Hanzalová ◽

P. Bartoš

Keyword(s):

Czech Republic ◽

Leaf Spot ◽

Tan Spot ◽

Grass Species ◽

The Czech Republic ◽

Pyrenophora Tritici Repentis ◽

Wheat Leaf ◽

Race 1 ◽

Race 4 ◽

Different Parts

Pyrenophora tritici-repentis, causal agent of tan spot, is one of the most important wheat leaf spot pathogens worldwide. The race structure of P. tritici-repentis isolates obtained from wheat (except one from noncereal grass species) in the Czech Republic was studied. The 86 monosporic isolates of P. tritici-repentis originated from different parts of the Czech Republic were grouped into five known races based on necrosis/chlorosis induction on standard differentials (Katepwa, Glenlea, 6B365, Salamouni). The isolates recovered from wheat were races 1, 2 and 4. Race 1 was the most frequent (50%), races 2 and 4 were found rarely (3% and 5% respectively). The isolate of P. tritici-repentis recovered from noncereal grass species was determined as race 4 which seems to be typical for noncereal hosts. The reaction of 30 isolates (42%) was difficult to be compared to reactions of so far identified P. tritici-repentis races. They have to be tested again on additional wheat genotypes.

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Fungicide and Cultivar Management of Leaf Spot Diseases of Winter Wheat in Western Canada

Plant Disease ◽

10.1094/pdis-12-17-1920-re ◽

2018 ◽

Vol 102 (9) ◽

pp. 1828-1833 ◽

Cited By ~ 3

Author(s):

H. R. Kutcher ◽

T. K. Turkington ◽

D. L. McLaren ◽

R. B. Irvine ◽

G. S. Brar

Keyword(s):

Winter Wheat ◽

Leaf Spot ◽

Field Experiments ◽

Leaf Growth ◽

Flag Leaf ◽

Management Program ◽

Tan Spot ◽

Leaf Spot Disease ◽

Western Canada ◽

Cultivar Selection

A complex of leaf-spotting diseases—tan spot, the Septoria complex, spot blotch, and powdery mildew—are frequently observed on winter wheat in western Canada; however, there are few studies indicating varietal differences in reaction to these diseases or the benefit of fungicide application. To determine the benefit of varietal improvement and multiple fungicide treatments and application timings, field experiments were conducted at six site-years in western Canada. Two cultivars varying in reaction to leaf spot diseases were used in combination with fungicide treatments. Disease severity ranged from trace to 64% of the combined flag and penultimate leaf area diseased, differed between cultivars, and was reduced from the check by some fungicide treatments. Yield improvement by fungicide treatment varied from 3.3 to 13.2% greater than the nontreated check. At two site-years, the split application of two half rates of fungicide resulted in the greatest yield; however, in both cases, the yield benefit did not differ from a single application at the flag leaf growth stage. Cultivar selection and fungicide use under environments conducive to disease are beneficial components of an integrated leaf spot disease management program for winter wheat in western Canada.

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Evaluation of a Multilocus Indel DNA Region for the Detection of the Wheat Tan Spot Pathogen Pyrenophora tritici-repentis

Plant Disease ◽

10.1094/pdis-03-16-0262-re ◽

2016 ◽

Vol 100 (11) ◽

pp. 2215-2225 ◽

Cited By ~ 4

Author(s):

Pao Theen See ◽

Caroline S. Moffat ◽

Joseph Morina ◽

Richard P. Oliver

Keyword(s):

Quantitative Polymerase Chain Reaction ◽

Tan Spot ◽

Qpcr Assay ◽

Rapid Screening ◽

Leaf Spot Disease ◽

Growth Stages ◽

Spot Disease ◽

Pyrenophora Tritici Repentis ◽

Specificity And Sensitivity ◽

Field Samples

Tan spot or yellow (leaf) spot disease of wheat (Triticum spp.) is caused by Pyrenophora tritici-repentis, a necrotrophic fungal pathogen that is widespread throughout the main wheat-growing regions in the world. This disease is currently the single most economically important crop disease in Australia. In this study, a real-time quantitative polymerase chain reaction (qPCR) assay was developed as a diagnostic tool to detect the pathogen on wheat foliar tissue. A multicopy locus (PtrMulti) present in the P. tritici-repentis genome was assessed for its suitability as a qPCR probe. The primer pair PtrMulti_F/R that targets the region was evaluated with respect to species specificity and sensitivity. A PtrMulti SYBR qPCR assay was developed and proved to be suitable for the identification and relative quantification of P. tritici-repentis with a detection limit of DNA levels at <0.1 pg. Variation of the PtrMulti copy number between the geographical representatives of P. tritici-repentis strains examined was minimal, with the range of 63 to 85 copies per genome. For naturally infected wheat field samples, the incidence of P. tritici-repentis DNA on leaves quantified by qPCR varied up to 1,000-fold difference in the concentration, with a higher incidence of DNA occurring on the lower canopy for most of the growth stages examined. At the early growth stages, qPCR assay was able to detect P. tritici-repentis DNA on the younger leaves in the absence of visible tan spot lesions. These results demonstrate the potential of PtrMulti probe to be used for early detection and rapid screening of tan spot disease on wheat plants.

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The epidemiology of leaf spot disease in a native prairie. I. The progression of disease with time

Canadian Journal of Botany ◽

10.1139/b75-122 ◽

1975 ◽

Vol 53 (10) ◽

pp. 1040-1050 ◽

Cited By ~ 10

Author(s):

R. J. Howard ◽

R. A. A. Morrall

Keyword(s):

Leaf Spot ◽

Late Summer ◽

Leaf Spot Disease ◽

Natural Ecosystems ◽

Lesion Area ◽

Spot Disease ◽

Native Prairie ◽

Pyrenophora Tritici Repentis ◽

Leaf Spots ◽

Plot Area

Leaf spot disease caused principally by Pyrenophora tritici-repentis was studied in 1969, 1970, and 1971 at Matador, Saskatchewan, in a native prairie dominated by Agropyron dasystachyum and A. smithii. The proportion of leaf area diseased (x), the lesion area per square metre of plot area, and the number of lesions per square metre of plot area were all used to measure disease on the total graminoids in the ecosystem. Disease progress curves for the first two variables differed considerably. The maximum x values in 1969, 1970, and 1971 were 0.034, 0.043, and 0.027 respectively. However the maximum lesion area per square metre of plot in 1970 was about twice that of the other 2 years. In 1970 there was less disease in an irrigated treatment and in a treatment in which the grass had been burned in late summer 1969, than in non-treated grassland. In 1970 and 1971 the distribution of individual leaf spots in 13 size classes varied at each sampling date, but most lesions were always less than 0.31 mm2. Overall, disease intensities were always low, despite sometimes apparently favorable environmental conditions. The results are discussed in relation to (inter alia) the study of plant disease epidemics in natural ecosystems and the variables generally used to measure diseases.

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TWO NEW SEVERE LEAF SPOT DISEASE ON FOREST TREES OF JALGAON (MAHARASTRA) INDIA

FLORA AND FAUNA ◽

10.33451/florafauna.v23i2pp288-290 ◽

2017 ◽

Vol 23 (2) ◽

Author(s):

S. A. FIRDOUSI

Keyword(s):

Leaf Spot ◽

Fungal Disease ◽

Leaf Spot Disease ◽

Forest Trees ◽

First Report ◽

Spot Disease ◽

Severe Leaf

During the survey of the forest fungal disease, of Jalgaon district, two severe leaf spot diseases on Lannae coromandelica and ( Ougenia dalbergioides (Papilionaceae) were observed in Jalgaon, forest during July to September 2016-17. The casual organism was identified as Stigmina lanneae and Phomopsis sp. respectively1-4,7. These are first report from Jalgaon and Maharashtra state.

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