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Dorrance AE, Kurle J, Robertson AE, Bradley CA, Giesler L, Wise K, Concibido VC. Pathotype Diversity of Phytophthora sojae in Eleven States in the United States. PLANT DISEASE 2016; 100:1429-1437. [PMID: 30686193 DOI: 10.1094/pdis-08-15-0879-re] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Pathotype diversity of Phytophthora sojae was assessed in 11 states in the United States during 2012 and 2013. Isolates of P. sojae were recovered from 202 fields, either from soil samples using a soybean seedling bioassay or by isolation from symptomatic plants. Each isolate was inoculated directly onto 12 soybean differentials; no Rps gene or Rps 1a, 1b, 1c, 1k, 3a, 3b, 3c, 4, 6, 7, or 8. There were 213 unique virulence pathotypes identified among the 873 isolates collected. None of the Rps genes were effective against all the isolates collected but Rps6 and Rps8 were effective against the majority of isolates collected in the northern regions of the sampled area. Virulence toward Rps1a, 1b, 1c, and 1k ranged from 36 to 100% of isolates collected in each state, while virulence to Rps6 and Rps8 was less than 36 and 10%, respectively. Depending on the state, the effectiveness of Rps3a ranged from totally effective to susceptible to more than 40% of the isolates. Pathotype complexity has increased in populations of P. sojae in the United States, emphasizing the increasing importance of stacked Rps genes in combination with high partial resistance as a means of limiting losses to P. sojae.
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Affiliation(s)
- A E Dorrance
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
| | - J Kurle
- Department of Plant Pathology, University of Minnesota, St. Paul 55108
| | - A E Robertson
- Department of Plant Pathology and Microbiology, Iowa State University, Ames 50011
| | - C A Bradley
- Department of Crop Sciences, University of Illinois, Urbana 61801
| | - L Giesler
- Department of Plant Pathology, University of Nebraska, Lincoln 68583
| | - K Wise
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47097
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Olivera PD, Kilian A, Wenzl P, Steffenson BJ. Development of a genetic linkage map for Sharon goatgrass (Aegilops sharonensis) and mapping of a leaf rust resistance gene. Genome 2013; 56:367-76. [PMID: 24099389 DOI: 10.1139/gen-2013-0065] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Aegilops sharonensis (Sharon goatgrass), a diploid wheat relative, is known to be a rich source of disease resistance genes for wheat improvement. To facilitate the transfer of these genes into wheat, information on their chromosomal location is important. A genetic linkage map of Ae. sharonensis was constructed based on 179 F2 plants derived from a cross between accessions resistant (1644) and susceptible (1193) to wheat leaf rust. The linkage map was based on 389 markers (377 Diversity Arrays Technology (DArT) and 12 simple sequence repeat (SSR) loci) and was comprised of 10 linkage groups, ranging from 2.3 to 124.6 cM. The total genetic length of the map was 818.0 cM, with an average interval distance between markers of 3.63 cM. Based on the chromosomal location of 115 markers previously mapped in wheat, the four linkage groups of A, B, C, and E were assigned to Ae. sharonensis (S(sh)) and homoeologous wheat chromosomes 6, 1, 3, and 2. The single dominant gene (designated LrAeSh1644) conferring resistance to leaf rust race THBJ in accession 1644 was positioned on linkage group A (chromosome 6S(sh)) and was flanked by DArT markers wpt-9881 (at 1.9 cM distal from the gene) and wpt-6925 (4.5 cM proximal). This study clearly demonstrates the utility of DArT for genotyping uncharacterized species and tagging resistance genes where pertinent genomic information is lacking.
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Affiliation(s)
- P D Olivera
- a Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, USA
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Olivera PD, Millet E, Anikster Y, Steffenson BJ. Genetics of resistance to wheat leaf rust, stem rust, and powdery mildew in Aegilops sharonensis. PHYTOPATHOLOGY 2008; 98:353-8. [PMID: 18944087 DOI: 10.1094/phyto-98-3-0353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Aegilops sharonensis (Sharon goatgrass) is a wild relative of wheat and a rich source of genetic diversity for disease resistance. The objectives of this study were to determine the genetic basis of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis and also the allelic relationships between genes controlling resistance to each disease. Progeny from crosses between resistant and susceptible accessions were evaluated for their disease reaction at the seedling and/or adult plant stage to determine the number and action of genes conferring resistance. Two different genes conferring resistance to leaf rust races THBJ and BBBB were identified in accessions 1644 and 603. For stem rust, the same single gene was found to confer resistance to race TTTT in accessions 1644 and 2229. Resistance to stem rust race TPMK was conferred by two genes in accessions 1644 and 603. A contingency test revealed no association between genes conferring resistance to leaf rust race THBJ and stem rust race TTTT or between genes conferring resistance to stem rust race TTTT and powdery mildew isolate UM06-01, indicating that the respective resistance genes are not linked. Three accessions (1644, 2229, and 1193) were found to carry a single gene for resistance to powdery mildew. Allelism tests revealed that the resistance gene in accession 1644 is different from the respective single genes present in either 2229 or 1193. The simple inheritance of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis should simplify the transfer of resistance to wheat in wide crosses.
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Affiliation(s)
- P D Olivera
- Department of Plant Pathology, University of Minnesota, St. Paul 55108, USA
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Olivera PD, Kolmer JA, Anikster Y, Steffenson BJ. Resistance of Sharon Goatgrass (Aegilops sharonensis) to Fungal Diseases of Wheat. PLANT DISEASE 2007; 91:942-950. [PMID: 30780426 DOI: 10.1094/pdis-91-8-0942] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Sharon goatgrass (Aegilops sharonensis) is a wild relative of wheat that is native to Israel and Lebanon. The importance of A. sharonensis as a source of new resistance genes for wheat warrants additional research on the characterization of accessions for economically important genes. Thus, the objectives of this study were to evaluate a collection of A. sharonensis accessions for resistance to seven important fungal diseases of wheat and assess the phenotypic diversity of the germplasm for disease reaction. The frequency of resistance in A. sharonensis was highest to powdery mildew (79 to 83%) and leaf rust (60 to 77%). Resistance to stem rust also was common, although the percentage of resistant accessions varied markedly depending on the pathogen race-from 13% to race TTTT to 72% to race QCCJ. The frequency of resistance was intermediate to stripe rust (45%) and low to tan spot (15 to 29%) and spot blotch (0 to 34%). None of the A. sharonensis accessions was resistant to Fusarium head blight. Many of the accessions tested exhibited heterogeneous reactions (i.e., had both resistant and susceptible plants) to one or more of the diseases, suggesting that heterozygosity may be present at some resistance loci. Substantial variation was observed in the level of diversity to individual diseases because Shannon's Equitability index ranged from 0.116 (for Fusarium head blight) to 0.994 (for tan spot). A high level of diversity was found both between and within collection sites. Moreover, differences in the geographic distribution of resistant accessions were observed. For example, accessions from northern Israel generally were less diverse and less resistant to leaf rust and stripe rust than accessions from more southern locations. Four A. sharonensis accessions were highly resistant to most of the diseases evaluated and may provide a source of unique resistance genes for introgression into cultivated wheat.
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Affiliation(s)
- P D Olivera
- Department of Plant Pathology, University of Minnesota, St. Paul 55108
| | - J A Kolmer
- United States Department of Agriculture-Agricultural Research Service, Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, St. Paul 55108
| | - Y Anikster
- Institute for Cereal Crops Improvement, Tel Aviv University, Ramat Aviv, Israel 69978
| | - B J Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul 55108
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McVey DV, Nazim M, Leonard KJ, Long DL. Patterns of Virulence Diversity in Puccinia triticina on Wheat in Egypt and the United States in 1998-2000. PLANT DISEASE 2004; 88:271-279. [PMID: 30812359 DOI: 10.1094/pdis.2004.88.3.271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Frequent epidemics of leaf rust in Egypt have been attributed to the appearance of new races virulent on commonly grown wheat cultivars. In 1998, 1999, and 2000, 726 isolates of Puccinia triticina collected in Egypt were tested on a set of 20 single Lr gene differential wheat lines, and 160 races were identified. Three races, MBDLQ, MCDLQ, and TCDMQ, were found in Egypt in all 3 years. Race MCDLQ occurred at >20% frequency each year. Virulences to wheat lines with Lr1, 3, 10, 14b, 15, 17, 23, and 26 occurred at >45% each year. Seven races found in Egypt also were found in either Israel, Sudan, Turkey, or Romania in 1998 or 1999, although the one race common to Sudan and Egypt was rare in Egypt (only 1 year, <1%). Four races found in Israel also were found in Egypt, and the similarity of virulence frequencies in Israel and Egypt indicate at least some exchange of inoculum. Romania and Turkey did not appear to be major sources of inoculum for leaf rust epidemics in Egypt. The level of genetic diversity in leaf rust collections in Egypt in 1998 to 2000 was similar to that of collections from the Southern and Central Plains of the United States in 1998 to 2000. The high diversity of races and the recurrence of common races in each year in Egypt as in the Southern and Central Plains of the United States is consistent with oversummer survival of P. triticina within Egypt or in a neighboring country. The buildup of races virulent on cultivars with the most commonly used Lr genes for resistance in Egypt also is consistent with year-round survival within Egypt or cyclical exchange of inoculum between Egypt and a neighboring country.
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Affiliation(s)
- D V McVey
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Cereal Disease Laboratory, St. Paul, MN 55108
| | - M Nazim
- Faculty of Agriculture, Minufiya University, Shibin el-Kom, Egypt
| | - K J Leonard
- USDA-ARS, Cereal Disease Laboratory, St. Paul, MN
| | - D L Long
- USDA-ARS, Cereal Disease Laboratory, St. Paul, MN
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Kolmer JA, Long DL, Kosman E, Hughes ME. Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2001. PLANT DISEASE 2003; 87:859-866. [PMID: 30812899 DOI: 10.1094/pdis.2003.87.7.859] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Collections of Puccinia triticina were obtained from rust-infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, Gulf Coast, California, Pacific Northwest, and Atlantic Coast States in order to determine the virulence of the wheat leaf rust fungus in 2001. Single uredinial isolates (477 in total) were derived from the wheat leaf rust collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, Lr30, LrB, Lr10, Lr14a, and Lr18. The isolates also were tested for virulence on adult plants with leaf rust resistance genes Lr12, Lr13, Lr22a, Lr22b, Lr34, Lr35, and Lr37. In the United States in 2001, 44 virulence phenotypes of P. triticina were found. Virulence phenotype MBDS, which is virulent to resistance gene Lr17, was the most common phenotype in the United States. MBDS was found in the Southeast, Great Plains, and Ohio Valley regions. Virulence phenotype THBJ, which is virulent to Lr16 and Lr26, was the second most common phenotype, and occurred almost exclusively in the north-central Great Plains region. Phenotype MCDS, which is virulent to Lr17 and Lr26, was the third most common phenotype and was found primarily in the Southeast, Ohio Valley, and Great Plains regions. The Southeast and Ohio Valley regions differed from the Great Plains region for predominant virulence phenotypes, which indicate that populations of P. triticina in those areas are not closely connected. The northern and southern areas of the Great Plains region differed for phenotypes with virulence to Lr16; however, the two areas had other phenotypes in common. Virulence to the adult plant resistance genes Lr35 and Lr37 was detected for the first time in North America in the MBDS, MCJS, and MCDS phenotypes.
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Affiliation(s)
| | - D L Long
- Plant Pathologist, USDA-ARS Cereal Disease Laboratory, University of Minnesota, St. Paul 55108
| | - E Kosman
- Institute for Cereal Crops Improvement, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - M E Hughes
- Biologist, USDA-ARS Cereal Disease Laboratory, University of Minnesota
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Long DL, Kolmer JA, Leonard KJ, Hughes ME. Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2000. PLANT DISEASE 2002; 86:981-986. [PMID: 30818559 DOI: 10.1094/pdis.2002.86.9.981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Collections of Puccinia triticina were obtained from rust infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, Gulf Coast, and Atlantic Coast States in order to determine the virulence of the wheat leaf rust fungus in 2000. Single uredinial isolates (1,120 in total) were derived from the wheat leaf rust collections and tested for virulence phenotype on 16 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In the United States in 2000, 54 virulence phenotypes of P. triticina were found. Virulence phenotypes MBDS and MCDS, which are virulent to resistance gene Lr17, were the first and third most common phenotypes in the United States and were found in the Great Plains and the Ohio Valley regions. MCRK, which is virulent to Lr26, was the second most common phenotype and was found primarily in the Southeast, Ohio Valley, and Northeast regions. In the northern area of the Great Plains, phenotypes with virulence to Lr16 increased in frequency from 1998 and 1999. The Southeast and Great Plains regions had different predominant virulence phenotypes, which indicates that populations of P. triticina in those areas are not closely connected. The northern and southern areas of the Great Plains region had the same predominant virulence phenotypes, indicating movement of virulence phenotypes of P. triticina within this region.
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Affiliation(s)
| | | | | | - M E Hughes
- Biologist, Cereal Disease Laboratory, USDA-ARS, Department of Plant Pathology, University of Minnesota, 1551 Lindig St., St. Paul 55108
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