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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #318244
Title: Virulence variations of Puccinia striiformis f. sp. tritici isolates sexually produced on Berberis spp. under natural conditions in China

Author
item WANG, Z. - Northwest Agriculture And Forestry University
item ZHAO, J. - Northwest Agriculture And Forestry University
item Chen, Xianming
item PENG, Y. - Northwest Agriculture And Forestry University
item JI, J. - Northwest Agriculture And Forestry University
item LV, Y. - Northwest Agriculture And Forestry University
item ZHAO, S. - Northwest Agriculture And Forestry University
item HUANG, L. - Northwest Agriculture And Forestry University
item KANG, Z. - Northwest Agriculture And Forestry University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2015
Publication Date: 1/5/2016
Citation: Wang, Z.Y., Zhao, J., Chen, X., Peng, Y.L., Ji, J.J., Lv, Y.J., Zhao, S.L., Huang, L.L., Kang, Z.S. 2016. Virulence variations of Puccinia striiformis f. sp. tritici isolates sexually produced on Berberis spp. under natural conditions in China. Plant Disease. 100(1):131-138..

Interpretive Summary: The stripe rust pathogen frequently causes significant yield losses in China, due to rapid development of new races that overcome resistance in wheat cultivars. Indirect evidence suggests that sexual reproduction occurs in the pathogen population in China, but direct evidence was still lacking. In this study, a large-scale survey of rust pustules on barberry plants was conducted in Gansu, Shaanxi, Tibet, and Xinjiang provinces in western China. A total of 9,297 single pustule samples were used to inoculate a susceptible wheat cultivar to identify the stripe rust fungus. Sixteen of the samples were identified as stripe rust fungus. When tested the 16 stripe rust samples on the wheat differentials for identifying races of the stripe rust pathogen, 15 of the samples had different virulence patterns, indicating that they were sexually produced through barberry. From the 16 samples, 118 single-uredinium isolates were obtained, from which 88 virulence patterns were identified when tested on 17 wheat lines each with a single resistance gene. The virulence patterns had relatively narrow virulence range. This study provides direct evidence that natural sexual reproduction occurs in the stripe rust population in China, but the frequency appears to be very low. The sexual reproduction on alternate host plants can generate a great virulence diversity, which may have contributed to the high variation in the stripe rust pathogen population in China. The study leads to a better understanding of the biology and genetics of the stripe rust pathogen.

Technical Abstract: The stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst), frequently causes significant yield losses in China, due to rapid development of new races that overcome resistance in wheat cultivars. Indirect evidence suggests that sexual reproduction occurs in the Pst population in China, but direct evidence was still lacking. In this study, a large-scale survey of barberry (Berberis spp.) was conducted in Gansu, Shaanxi, Tibet, and Xinjiang provinces in western China. A total of 9,297 single aecial (SA) samples were used to inoculate a susceptible wheat cultivar to identify samples of Pst. Sixteen of the SA samples were identified as Pst. When tested on the wheat differentials for identifying Pst races, 15 of the 16 SA samples had different virulence patterns, indicating that they were sexually produced through barberry. From the 16 SA samples, 118 single-uredinium (SU) isolates were obtained, from which 88 virulence patterns were identified when tested on 17 Yr single-gene lines. The virulence patterns had relatively narrow virulence spectra, ranging from 0 to 9 with a mean of 4 virulences per SU isolates. Of the 17 Yr genes, no virulences were detected for Yr5, Yr10, and Yr15; virulences to YrTr1, Yr24, and Yr27 were extremely low (< 3%); those to YrSP, Yr9, Yr28, and Yr2 were low (13.6-28.0%); those to Yr7, Yr17, Yr8, and YrExp2 were moderate (33.1-48.3%); and those to Yr6, Yr44, and Yr25 were high (52.5-72.9%). This study provides direct evidence that natural sexual reproduction occurs in the Pst population in China, but the frequency appears to be very low. The sexual reproduction on alternate host plants can generate a great virulence diversity, which may have contributed to the high variation in the Pst population in China.