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| Population Diversity of Puccinia graminis is Sustained Through Sexual Cycle on Alternate Hosts |
| Yue Jin, Matt Rouse , Jim Groth |
1.USDA-ARS, Cereal Disease Laboratory, University of Minnesota, St. Paul, MN 55108, USA
2.Colville, WA 99114, USA |
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摘要 A high degree of virulence diversity has been maintained in the population of Puccinia graminis f. sp. tritici (Pgt) in northwestern United States. Although Berberis vulgaris is present in the region and Pgt has been isolated from aecial infections on B. vulgaris, the population is too diverse to be explained by the limited presence of B. vulgaris alone. Since 2008, we have isolated P. graminis from aecial infections on fruits of Mahonia repens and Mahonia aquifolium from northwestern United States. These two native woody shrub species, widely distributed in western North America, were once classified as resistant to P. graminis based on artificial inoculations. By isolating P. graminis from aecia, we established that M. repens and M. aquifolium along with B. vulgaris (albeit infrequent) serve as the alternate hosts of P. graminis in the region. The isolates of P. graminis from Mahonia of North America had diverse virulence patterns and most of the isolates could be differentiated on Morocco, Line E, Chinese Spring, Little Club, LMPG-6, Rusty, and other genotypes that are considered to be universally susceptible to most Pgt isolates. This discovery explained the persistence of virulence diversity of Pgt observed in isolates derived from uredinia on cereal crops in the region. In addition to cereal crops, uredinial stage of the P. graminis population is sustained by wild grasses, especially Elymus glaucus, a native grass sharing the same habitat with the rusted Mahonia spp. Although virulence to some important stem rust resistance genes was observed in some isolates derived from Mahonia of North America when tested against single stem rust resistance gene stocks, the overall virulence is very limited in these isolates. This is likely a result of limited selection pressure on the rust population. In contrast to northwestern United Sates, the Pgt population in east of the Rocky Mountains of North America has declined steadily with a single race, QFCSC, being predominant in the last decade. This decline is likely due to a combination of factors, of which a lack of sexual recombination in the region is perhaps the most important one.
Abstract A high degree of virulence diversity has been maintained in the population of Puccinia graminis f. sp. tritici (Pgt) in northwestern United States. Although Berberis vulgaris is present in the region and Pgt has been isolated from aecial infections on B. vulgaris, the population is too diverse to be explained by the limited presence of B. vulgaris alone. Since 2008, we have isolated P. graminis from aecial infections on fruits of Mahonia repens and Mahonia aquifolium from northwestern United States. These two native woody shrub species, widely distributed in western North America, were once classified as resistant to P. graminis based on artificial inoculations. By isolating P. graminis from aecia, we established that M. repens and M. aquifolium along with B. vulgaris (albeit infrequent) serve as the alternate hosts of P. graminis in the region. The isolates of P. graminis from Mahonia of North America had diverse virulence patterns and most of the isolates could be differentiated on Morocco, Line E, Chinese Spring, Little Club, LMPG-6, Rusty, and other genotypes that are considered to be universally susceptible to most Pgt isolates. This discovery explained the persistence of virulence diversity of Pgt observed in isolates derived from uredinia on cereal crops in the region. In addition to cereal crops, uredinial stage of the P. graminis population is sustained by wild grasses, especially Elymus glaucus, a native grass sharing the same habitat with the rusted Mahonia spp. Although virulence to some important stem rust resistance genes was observed in some isolates derived from Mahonia of North America when tested against single stem rust resistance gene stocks, the overall virulence is very limited in these isolates. This is likely a result of limited selection pressure on the rust population. In contrast to northwestern United Sates, the Pgt population in east of the Rocky Mountains of North America has declined steadily with a single race, QFCSC, being predominant in the last decade. This decline is likely due to a combination of factors, of which a lack of sexual recombination in the region is perhaps the most important one.
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Received: 09 July 2013
Accepted:
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Corresponding Authors:
Yue Jin, E-mail: Yue.Jin@ARS.USDA.GOV
E-mail: Yue.Jin@ARS.USDA.GOV
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| About author: Yue Jin, E-mail: Yue.Jin@ARS.USDA.GOV |
Cite this article:
Yue Jin, Matt Rouse , Jim Groth.
2014.
Population Diversity of Puccinia graminis is Sustained Through Sexual Cycle on Alternate Hosts. Journal of Integrative Agriculture, 13(2): 262-264.
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| Jin Y. 2010. Role of the alternate host Berberis spp. in generating new races of Puccinia graminis and P. striiformis. Euphytica, 179, 105-108 Jin Y, Szabo L J, Carson M. 2010. Century-old mystery of Puccinia striiformis life history solved with the identification of Berberis as an alternate host. Phytopathology, 100, 432-435 Kolmer J, Chen X, Jin Y. 2009. Diseases which challenge global wheat production-the wheat rusts. In: Carver B F, ed., Wheat Science and Trade. Wiley-BlackWell, USA. pp. 89-124 Roelfs A P. 1982. Effects of barberry eradication on stem rust in the United States. Plant Disease, 66, 177-181 Roelfs A P, Groth J V. 1980. A comparison of virulence phenotypes in wheat stem rust populations reproducing sexually and asexually. Phytopathology, 70, 855-862 Whetstone R D, Atkinson T A, Spaulding D D. 1997. BERBERIDACEAE Jussieu - barberry family. In: Flora of North America Editorial Committee, ed., Flora of North America. vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York. pp. 272-299 |
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