Comments on “Determination of heterozygosity for avirulence/virulence loci through sexual hybridization of Puccinia striiformis f. sp. tritici”

Over the past decades Puccinia striiformis f.sp. tritici (Pst) has developed into one of the most, if not the most important fungal pathogen in wheat production worldwide. In China, Pst has caused numerous epidemics with partially devastating yield losses^[ 1^]. The occurrence of the “warrior” race in Europe in 2011 also caused significant problems^[ 2^]. Pst, like other obligate biotrophs, is characterized by a high degree of genetic variability, especially with respect avirulence/virulence development on specific host varieties. This variability may be caused by mutations, somatic recombination, or recombination during the sexual stage of the fungus. The discovery of the hitherto unknown alternate host for Pst in 2010^[ 3^] put a new focus on the role of sexual recombination in this variability^[ 4, 5^]. With now 35 barberry species identified as potential alternate host for Pst in one of China’s bread baskets (Gansu, Sichuan, Shaanxi, Yunnan and Tibe)^[ 6, 7^], elucidating the role of the sexual cycle of Pst has become even more important. The work entitled “Determination of heterozygosity for avirulence/virulence loci through sexual hybridization of Puccinia striiformis f. sp. tritici” by Yuan TIAN, Gangming ZHAN, Xia LU, Jie ZHAO, Lili HUANG, and Zhensheng KANG, in this issue (DOI: 10.15302/J-FASE-2016114), is an important work in the light of giving breeders some indication as to which wheat varieties to use for future crosses. From the 25 wheat varieties tested, 17 turned out to carry resistance genes for which the corresponding Pst avirulence/virulence genes turned out to be heterozygous. Such lines should be excluded from future breeding programs as chances are high that resistances generated in the new cultivars will be rapidly overcome. As such this paper constitutes a major advance in understanding the intricate interaction of Pst and its host wheat, and at the same time provides practical cues for future breeding programs.

References

[1] Kang Z, Zhao J, Han D, Zhang H, Wang X, Wang C, Han Q, Guo J, Huang L. 2010. Status of wheat rust research and control in China.Bgri Technical Workshop Oral Presentations Full Paper & Abstracts May , 2010: 50–69

[2] Sørensen C K, Hovmøller M S, Leconte M, Dedryver F, de Vallavieille-Pope C. New races of Puccinia striiformis found in Europe reveal race specificity of long-term effective adult plant resistance in wheat. Phytopathology, 2014, 104(10): 1042–1051

[3] Jin Y, Szabo L J, Carson M. Century-old mystery of Puccinia striiformis life history solved with the identification of Berberis as an alternate host. Phytopathology, 2010, 100(5): 432–435

[4] Wang Z, Zhao J, Chen X, Peng Y, Ji J, Zhao S, Lv Y, Huang L, Kang Z. Virulence variations of Puccinia striiformis f. sp. tritici isolates collected from Berberis spp. in China. Plant Disease, 2016, 100(1): 131–138

[5] Zhao J, Wang M, Chen X, Kang Z. Role of alternate hosts in epidemiology and pathogen variation of cereal rusts. Annual Review of Phytopathology, 2016, 54(1): 207–228

[6] Zhao J, Wang L, Wang Z, Chen X, Zhang H, Yao J, Zhan G, Chen W, Huang L, Kang Z. Identification of eighteen Berberis species as alternate hosts of Puccinia striiformis f. sp. tritici and virulence variation in the pathogen isolates from natural infection of barberry plants in China. Phytopathology, 2013, 103(9): 927–934

[7] Zhao J, Zhao S, Peng Y, Qin J, Huang L, Kang Z. Investigation on geographic distribution of six Berberis spp. serving as alternate host for Puccinia striiformis f. sp. tritici in Linzhi, Tibet. Acta Phytopathologica Sinica, 2016, 46(1): 103–111

RIGHTS & PERMISSIONS

The Author(s) 2017. Published by Higher Education Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0)