Virulence Characterization of International Collections of the Wheat Stripe Rust Pathogen, Puccinia striiformis f. sp. tritici

Abstract

Wheat stripe rust (yellow rust [Yr]), caused by Puccinia striiformis f. sp. tritici, is an economically important disease of wheat worldwide. Virulence information on P. striiformis f. sp. tritici populations is important to implement effective disease control with resistant cultivars. In total, 235 P. striiformis f. sp. tritici isolates from Algeria, Australia, Canada, Chile, China, Hungary, Kenya, Nepal, Pakistan, Russia, Spain, Turkey, and Uzbekistan were tested on 20 single Yr-gene lines and the 20 wheat genotypes that are used to differentiate P. striiformis f. sp. tritici races in the United States. The 235 isolates were identified as 129 virulence patterns on the single-gene lines and 169 virulence patterns on the U.S. differentials. Virulences to YrA, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, YrUkn, Yr28, Yr31, YrExp2, Lemhi (Yr21), Paha (YrPa1, YrPa2, YrPa3), Druchamp (Yr3a, YrD, YrDru), Produra (YrPr1, YrPr2), Stephens (Yr3a, YrS, YrSte), Lee (Yr7, Yr22, Yr23), Fielder (Yr6, Yr20), Tyee (YrTye), Tres (YrTr1, YrTr2), Express (YrExp1, YrExp2), Clement (Yr9, YrCle), and Compair (Yr8, Yr19) were detected in all countries. At least 80% of the isolates were virulent on YrA, Yr2, Yr6, Yr7, Yr8, Yr17, YrUkn, Yr31, YrExp2, Yr21, Stephens (Yr3a, YrS, YrSte), Lee (Yr7, Yr22, Yr23), and Fielder (Yr6, Yr20). Virulences to Yr1, Yr9, Yr25, Yr27, Yr28, Heines VII (Yr2, YrHVII), Paha (YrPa1, YrPa2, YrPa3), Druchamp (Yr3a, YrD, YrDru), Produra (YrPr1, YrPr2), Yamhill (Yr2, Yr4a, YrYam), Tyee (YrTye), Tres (YrTr1, YrTr2), Hyak (Yr17, YrTye), Express (YrExp1, YrExp2), Clement (Yr9, YrCle), and Compair (Yr8, Yr19) were moderately frequent (>20 to <80%). Virulence to Yr10, Yr24, Yr32, YrSP, and Moro (Yr10, YrMor) was low (≤20%). Virulence to Moro was absent in Algeria, Australia, Canada, Kenya, Russia, Spain, Turkey, and China, but 5% of the Chinese isolates were virulent to Yr10. None of the isolates from Algeria, Canada, China, Kenya, Russia, and Spain was virulent to Yr24; none of the isolates from Algeria, Australia, Canada, Nepal, Russia, and Spain was virulent to Yr32; none of the isolates from Australia, Canada, Chile, Hungary, Kenya, Kenya, Nepal, Pakistan, Russia, and Spain was virulent to YrSP; and none of the isolates from any country was virulent to Yr5 and Yr15. Although the frequencies of virulence factors were different, most of the P. striiformis f. sp. tritici isolates from these countries shared common virulence factors. The virulences and their frequencies and distributions should be useful in breeding stripe-rust-resistant wheat cultivars and understanding the pathogen migration and evolution.

Molecular Mapping of Stripe Rust Resistance Gene Yr76 in Winter Club Wheat Cultivar Tyee

“…tritici races as it provides very clear low and high responses with low probability of misclassification (Sharma-Poudyal et al 2013;Wan and Chen 2014;Wan et al 2016;Zhan et al 2012). Race groups separated by virulence and avirulence on Tyee correspond to genetic groups separated by molecular markers A.…”

“…tritici population in the United States can be separated into two major groups based on virulence or avirulence to YrTye, and that the two major virulence groups correspond to two major genetic groups determined using molecular markers Wan and Chen 2014;Wan et al 2016). In general, the frequencies of virulence to Tyee were low in other countries compared with the United States (Sharma-Poudyal et al 2013;Zhan et al 2012;A. M. Wan and X. M. Chen, unpublished data).…”

“…Variation in the response of Tyee was also observed among P. striiformis f. sp. tritici isolates from Australia, Canada, Chile, China, Ecuador, Hungary, Italy, Kenia, Nepal, Turkey, and Uzbekistan (Sharma-Poudyal et al 2013;Zhan et al 2012;A. M. Wan and X. M. Chen, unpublished data).…”

Marker assisted separation of resistance genes Rph22 and Rym16 Hb from an associated yield penalty in a barley: Hordeum bulbosum introgression line

“…However, these single dominant, major resistance genes are often rapidly overcome upon widespread cultivation. For example, from 235 worldwide isolates of wheat stripe rust, virulence was detected for all but two R genes tested (Yr5 and Yr15) (Sharma-Poudyal et al 2012). In contrast, partial resistance genes, as a group, are generally considered to be a more durable mechanism of disease resistance because of their polygenic nature and non-race specificity (Brown 2002 (Dyck et al 1966), Lr34/Yr18/Pm38 from the wheat variety 'Terenzio' (Dyck 1987) and mlo from mutants and Ethiopian landraces of barley (Jørgensen 1992).…”

Maxwell: El Cultivar De Trigo Que Ha Superado Las Barreras Productivas en El Sur De Chile

“…Comunicación personal). La caracterización de virulencias, realizada en la Universidad de Washington en las que participaron muestras de roya estriada de Chile, confirmaron la alta efectividad del gene Yr 5, el cual se encontraría presente en Maxwell, y de otros genes como YrSp y Yr15 (Sharma-Poudyal et al, 2013). Mediante el monitoreo anual que se realiza en INIA CRI Quilamapu con las isolineas para Puccinia triticina se puede concluir en la temporada agrícola 2015-16 que Lr9 presente en NIL-Thatcher-Lr9-Transfer y Lr24 en NIL-Thathcher-Lr 24-Agent no confieren protección completa a la roya de la hoja.…”