Evaluation of the Potential Risk of the Emerging Yr5-Virulent Races of Puccinia striiformis f. sp. tritici to 165 Chinese Wheat Cultivars

Abstract

In 2017, a new race (TSA-6) of the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici, virulent to resistance gene Yr5 were detected in China. However, whether Chinese wheat cultivars are resistant to the new races was unknown. In this study, two isolates (TSA-6 and TSA-9) with virulence to Yr5 were tested on other wheat Yr gene lines for their avirulence/virulence patterns and used, together with prevalent races CYR32 and CYR34 without the Yr5 virulence, to evaluate 165 major Chinese wheat cultivars for their reactions. Isolates TSA-6 and TSA-9 had similar but different virulence spectra, and therefore should be considered as two different races. Their avirulent/virulence patterns were remarkably different from that of CYR34 but quite similar to that of CYR32. Of the 165 wheat cultivars, 21 had all-stage resistance to TSA-6, 34 to TSA-9, and 20 to both races. Adult-plant resistance (APR) was detected in 35 cultivars to TSA-6 and 27 to TSA-9, but only 3 cultivars showed APR to both new races. Slow rusting resistance was observed in 24 cultivars to TSA-6 and of 33 to TSA-9. Analysis of variance (ANOVA) of disease index indicated a significant difference among cultivars, but not among the four races. Based on the molecular marker data, a low percentage of wheat cultivars carried Yr5, Yr7, Yr10, Yr15, Yr26, and/or YrSP. As TSA-6 and TSA-9 can be a serious threat to wheat production in China, monitoring TSA-6, TSA-9, and other races are continually needed.

Evaluation of resistance and molecular detection of resistance genes to wheat stripe rust of 82 wheat cultivars in Xinjiang, China

“…The deployment of wheat cultivars carrying multiple resistance genes in epidemiological regions can theoretically control disease outbreak. Wheat cultivars with whole growth stage resistance have been grown in epidemiological regions now and have achieved good results in the control of wheat stripe rust 44 .…”

Fine mapping and characterization of rust resistance genes Lr53 and Yr35 introgressed from Aegilops species

“…tritici (Pst), the causal agents of wheat leaf rust and stripe rust, are two devastating fungal diseases threatening global wheat production. In recent years, leaf and stripe rust pathogens have become increasingly problematic due to the emergence of more virulent and aggressive pathogen races (Boshoff et New Pst races virulent on wheat genotypes with Yr5 have been reported in various countries, including China, Australia, India, and Turkey (Tekin et al 2021;Zhang et al 2022). Race CYR32 was responsible for severe stripe rust epidemics in China in 2001/2002, which led to signi cant yield losses across approximately 6.6 million hectares of wheat area (Wan et al 2004).…”

Mapping and characterization of rust resistance genes Lr53 and Yr35 introgressed from Aegilops species

“…New Pst races virulent on wheat genotypes with Yr5 have been reported in various countries, including China, Australia, India, and Turkey (Tekin et al 2021 ; Zhang et al 2022 ). Race CYR32 was responsible for severe stripe rust epidemics in China in 2001/2002, which led to significant yield losses across approximately 6.6 million hectares of wheat area (Wan et al 2004 ).…”