Virulence phenotypes of the wheat leaf rust pathogen, Puccinia triticina, in the United States 2018-2020

Plant Disease ◽  
2022 ◽  
Author(s):  
James Kolmer ◽  
Oluseyi Fajolu

Collections of wheat leaves infected with the leaf rust fungus, Puccinia triticina, were obtained from the southeastern states, the Ohio Valley, the Great Plains, and Washington in 2018, 2019 and 2020 to determine the prevalent virulence phenotypes in the wheat growing regions of the United States. In the hard red winter wheat region of the southern and mid Great Plains, MNPSD, and MPPSD were the two most common phenotypes in 2018 and 2019. In 2020 BBBQD with high virulence to durum wheat was the most common phenotype in the southern Great Plains. In the hard red spring wheat region of the northern Great Plains, MNPSD, MPPSD, MBDSD, and TBBGS were the predominant phenotypes. In the soft red winter wheat region of the southeastern states and Ohio Valley region, MBTNB, MCTNB, and MNPSD were the three most common phenotypes. Collections in Washington had phenotypes LBDSG, LCDSG, LCDJG, and MBDSB that were not found in any other region. Isolates with virulence to Lr11 were most frequent in the southeastern states, and Ohio Valley regions. The frequency of isolates with virulence to Lr39 was highest in the Great Plains region and frequency of isolates with virulence to Lr21 was highest in the northern Great Plains region. Selection of virulence phenotypes by leaf rust resistance genes in the different market classes of wheat, combined with the effects of clonal reproduction, overwintering in southern regions, and low migration between the Great Plains region and eastern wheat producing regions, has maintained the different P. triticina populations in the United States.

Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.


Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1768-1773 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina obtained from wheat fields and breeding plots in the Great Plains, Ohio River Valley, and southeastern states, were tested for virulence in 2014 in order to determine the virulence of the wheat leaf rust pathogen population in the United States. Single uredinial isolates (380 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2014, 55 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TBBGS, and TCRKG were the three most common phenotypes. Phenotypes MBTNB and TCRKG are both virulent to Lr11, and TCRKG is also virulent to Lr18 and Lr26. MBTNB and TCRKG were most common in the soft red winter wheat region of the southeastern states and the Ohio Valley. Phenotype TBBGS is virulent to Lr39, which is present in the hard red winter wheat cultivars, and Lr21, which is present in the hard red spring wheat cultivars. Isolates with virulence to Lr11, Lr18, and Lr26 were most common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21 and Lr39 were most common in the hard red wheat region of the southern and northern Great Plains.


Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 2113-2120 ◽  
Author(s):  
J. A Kolmer

Samples of wheat leaves infected with the leaf rust fungus, Puccinia triticina, were obtained in 2017 from agricultural experiment station plots, demonstration plots, and farm fields in the Great Plains, the Ohio Valley, the southeastern states, California, and Washington in order to determine the prevalent virulence phenotypes present in the United States. A total of 65 virulence phenotypes were identified among the 469 single uredinial isolates that were tested on 20 near-isogenic lines of Thatcher wheat that differ for leaf rust resistance genes. Virulence phenotypes MBTNB at 11.3% of the overall population, and MCTNB at 7.0%, were the first and third most common phenotypes. Both phenotypes were found mostly in the southeastern states and Ohio Valley region. Phenotype TFTSB at 10.9% was the second most common phenotype and was found mostly in southern Texas. Virulence to leaf rust resistance gene Lr39, which is present in hard red winter wheat cultivars, was highest in the Great Plains region. Virulence to Lr11 and Lr18, which are present in soft red winter wheat cultivars, was highest in the southeastern states and Ohio Valley region. Virulence to Lr21, which is present in hard red spring wheat cultivars, was highest in the northern Great Plains region. The predominate P. triticina phenotypes from the soft red winter wheat regions of the southeastern states and Ohio Valley area differed from those in the hard red winter and hard red spring wheat areas of the Great Plains region. Collections from Washington had unique virulence phenotypes that had not been previously detected.


Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1103-1108 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, southeastern states, Oregon, and Washington State in order to determine the virulence of the wheat leaf rust population in 2011. Single uredinial isolates (440 total) were derived from the collections and tested for virulence phenotype on 18 lines of Thatcher wheat and a winter wheat line that are near-isogenic for 19 leaf rust resistance genes. In 2011, 87 virulence phenotypes were described in the United States. Virulence phenotypes TBBGJ, MLDSD, and TCRKG were the three most common phenotypes. Phenotype TBBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Phenotype MLDSD is virulent to Lr17 and Lr39/41 and was widely distributed throughout the United States. Phenotype TCRKG is virulent to Lr11, Lr18, and Lr26 and was found mostly in the soft red winter wheat region in the eastern United States. Isolates with virulence to Lr39/41 and avirulence to Lr9 were prevalent in the Great Plains region for the first time. Virulence to Lr21 was present in five virulence phenotypes mostly from the spring wheat region of the northern Great Plains.


Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 538-544 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes

In 2007, leaf rust of wheat was severe throughout the Great Plains region of North America. Yield losses in wheat due to leaf rust were estimated to be 14% in Kansas. Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio River Valley, southeast, California, and Washington State in order to determine the virulence of the wheat leaf rust population in 2007. Single uredinial isolates (868 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr21, and Lr28, and on winter wheat lines with genes Lr41 and Lr42. Fifty-two virulence phenotypes were found. Virulence phenotypes TDBJG, MFPSC, and TDBJH were among the four most common phenotypes and were all virulent to resistance gene Lr24. These phenotypes were found throughout the Great Plains region. Phenotype MLDSD, with virulence to Lr9, Lr17, and Lr41, was also widely distributed in the Great Plains. In the soft red winter wheat region of the southeastern states, phenotypes TCRKG, with virulence to genes Lr11, Lr26, and Lr18, and MFGJH, with virulence to Lr24, Lr26, and Lr11, were among the common phenotypes. Virulence phenotypes with virulence to Lr16 were most frequent in the spring wheat region of the northern Great Plains. Virulence phenotypes with virulence to Lr11, Lr18, and Lr26 were most common in the soft red winter areas of the southeastern states and Ohio Valley. Virulence to Lr21 was not found in any of the tested isolates.


Plant Disease ◽  
2018 ◽  
Vol 102 (6) ◽  
pp. 1066-1071 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Leaves of wheat infected with the leaf rust fungus Puccinia triticina were obtained from farm fields and breeding plots at experimental stations in the Great Plains, Ohio River Valley, and southeastern states in 2016 in order to identify virulence phenotypes prevalent in the United States in different wheat-growing regions. In total, 496 single uredinial isolates derived from the leaf rust collections were tested for virulence to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes. In total, 71 virulence phenotypes were described in the United States in 2016. The three most common virulence phenotypes across the United States were MBTNB, MBDSD, and TNBJJ. Phenotype MBTNB is virulent to Lr11, and was most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype MBDSD is virulent to Lr17 and Lr39, and was most common in the hard red winter wheat area of the southern Great Plains. Phenotype TNBJJ is virulent to Lr24 and Lr39, which are present in the hard red winter wheat cultivars. The P. triticina population in the United States was characterized by two major regional groups of virulence phenotypes in the Great Plains region where hard red winter and spring wheat cultivars are grown, and in the southeastern states and Ohio Valley region where soft red winter wheat cultivars are grown. Isolates from New York State differed the most for virulence compared with the other two major regions.


Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1241-1246 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio River Valley, southeast, California, and Washington State in order to determine the virulence of the wheat leaf rust population in 2006. Single uredinial isolates (718 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr2, and Lr28 and winter wheat lines with genes Lr41 and Lr42. In the United States in 2006, 56 virulence phenotypes were found. Virulence phenotypes TDBJG, TDBGG, and TDBJH were among the four most common phenotypes and were all virulent to resistance gene Lr24. These phenotypes were found throughout the Great Plains region. Phenotype MLDSD with virulence to Lr9, Lr17, and Lr41 was also widely distributed in the Great Plains. In the soft red winter wheat region of the southeastern states, phenotypes TCRKG and MBRKG with virulence to genes Lr11, Lr26, and Lr18 were among the common phenotypes. Virulence phenotypes with virulence to Lr16 were most frequent in the spring wheat region of the northern Great Plains. Virulence to Lr21 was not found in any of the tested isolates.


Plant Disease ◽  
2014 ◽  
Vol 98 (8) ◽  
pp. 1145-1150 ◽  
Author(s):  
J. A Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by United States Department of Agriculture–Agricultural Research Service personnel and cooperators in the Great Plains, Ohio River Valley, southeastern states, and Washington State and Idaho in order to determine the virulence of the wheat leaf rust population in 2012. Single uredinial isolates (501 in total) were derived from the collections and tested for virulence phenotype on 20 lines of ‘Thatcher’ wheat that are near-isogenic for leaf rust resistance genes. In 2012, 74 virulence phenotypes were described in the United States. Virulence phenotypes TNBGJ, TCRKG, and MBTNB were the three most common phenotypes. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Phenotype TCRKG is virulent to Lr11, Lr18, and Lr26 and was found mostly in the soft red winter wheat region in the eastern United States. Phenotype MBTNB is virulent to Lr11 and was also found mostly in the soft red winter wheat region. The frequency of isolates with virulence to Lr39/41, which is present in many hard red winter wheat cultivars in the Great Plains region, continued to increase. Isolates with virulence to Lr21, which is present in many hard red spring wheat cultivars, also continued to increase in frequency in the northern Great Plains region.


Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 981-986 ◽  
Author(s):  
D. L. Long ◽  
J. A. Kolmer ◽  
K. J. Leonard ◽  
M. E. Hughes

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.


Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 775-780 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected wheat (Triticum aestivum) leaves provided by cooperators throughout the United States and from surveys of wheat fields and wheat breeding plots by USDA-ARS personnel in the Great Plains, Ohio River Valley, Southeast, and Washington State in order to determine the virulence of the wheat leaf rust population in 2008. Single uredinial isolates (730 in total) were derived from the 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, Lr18, Lr21, Lr28, and a winter wheat line with Lr41. Forty-eight virulence phenotypes were described. Virulence phenotypes TDBGG, TCRKG, and MLDSD were the three most common phenotypes. TDBGG is virulent to Lr24 and was found in both the soft red winter wheat and hard red winter wheat regions. Phenotype TCRKG is virulent to Lr11, Lr18, and Lr26 and is found mostly in the soft red winter wheat region in the eastern United States. Phenotype MLDSD is virulent to Lr17 and Lr41 and was widely distributed in the Great Plains. Virulence to Lr21 was not found in any of the tested isolates. Virulence to Lr11 and Lr18 increased in 2008 in the soft red winter wheat regions. Two separate epidemiological zones of P. triticina in the soft red winter wheat region of the southern and eastern states and in the hard red wheat region of the Great Plains were described.


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