Dissection of loci conferring resistance to stripe rust at the adult-plant stage of Chinese wheat landraces in the middle and lower reaches of the Yangtze River via genome-wide association study

Authors: CHENG, YUKUN - Sichuan Agricultural University; LI, JIAN - Sichuan Agricultural University; YAO, FANGJIE - Sichuan Agricultural University; LONG, LI - Sichuan Agricultural University; WANG, YUQI - Sichuan Agricultural University; WU, YU - Sichuan Agricultural University; LI, JING - Sichuan Agricultural University; YE, XUELING - Sichuan Agricultural University; WANG, JIRI - Sichuan Agricultural University; JIANG, QIANTAO - Sichuan Agricultural University; KANG, HOUYANG - Sichuan Agricultural University; LI, WEI - Sichuan Agricultural University; QI, PENGFEI - Sichuan Agricultural University; LIU, YAXI - Sichuan Agricultural University; DENG, MEI - Sichuan Agricultural University; MA, JIAN - Sichuan Agricultural University; Chen, Xianming; ZHENG, YOULIANG - Sichuan Agricultural University; WEI, YUMING - Sichuan Agricultural University; CHEN, GUOYUE - Sichuan Agricultural University

Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2019
Publication Date: 7/27/2019
Citation: Cheng, Y., Li, J., Yao, F., Long, L., Wang, Y., Wu, Y., Li, J., Ye, X., Wang, J., Jiang, Q., Kang, H., Li, W., Qi, P., Liu, Y., Deng, M., Ma, J., Chen, X., Zheng, Y., Wei, Y., Chen, G. 2019. Dissection of loci conferring resistance to stripe rust at the adult-plant stage of Chinese wheat landraces in the middle and lower reaches of the Yangtze River via genome-wide association study. Plant Science. VOLUME 287, 110204. https://doi.org/10.1016/j.plantsci.2019.110204.
DOI: https://doi.org/10.1016/j.plantsci.2019.110204

Interpretive Summary: Stripe rust is a devastating foliar disease of wheat in China. To identify adult-plant resistance (APR) genes for stripe-rust resistance, a panel of 188 wehat accessions derived from the middle and lower reaches of the Yangtze River were inoculated with a mixture of Chinese stripe rust races and resistance evaluated under field conditions in five environments at adult-plant stages. Seventy-three accessions showed stable resistance. Combining phenotypic datasets from multiple field experiments with high-quality Diversity Arrays Technology and simple sequence repeat markers, we detected 21 marker–trait associations spanning 18 quantitative trait loci (QTLs) on nine chromosomes. Single QTLs explained 9.67% to 16.14% of the observed phenotypic variation. Nine QTLs co-localized with previously reported genes or genomic regions. The remaining QTLs were potentially novel loci and associated with adult-stage stripe-rust resistance. Two novel QTLs, QYr.sicau-3B.2 and QYr.sicau-5B.3, located on chromosomes 3B and 5B significantly explained 16.14% and 11.16% of the phenotypic variation, respectively. Haplotype analysis revealed that accessions carrying APR variants or their combinations showed enhanced degrees of resistance. The potentially novel loci or genomic regions associated with APR may be useful to improve stripe-rust resistance in current wheat cultivars and for future isolation of stripe-rust resistance genes.

Technical Abstract: Stripe rust (Yr), caused by the fungal pathogen Puccinia striiformis f. sp. tritici, is a devastating foliar disease of wheat in China. Chinese wheat landraces originating from the middle and lower reaches of the Yangtze River are potential stripe-rust resistance resources, yet the genomic regions controlling stripe-rust resistance, particularly adult-plant resistance (APR), show extreme complexity and are poorly known. To identify APR genes for stripe-rust resistance, a panel of 188 accessions derived from the middle and lower reaches of the Yangtze River were inoculated with a mixture of Chinese P. striiformis f. sp. tritici races and resistance evaluated under field conditions in five environments at adult-plant stages. Seventy-three accessions showed degrees of stable resistance. Combining phenotypic datasets from multiple field experiments with high-quality Diversity Arrays Technology and simple sequence repeat markers, we detected 21 marker–trait associations spanning 18 quantitative trait loci (QTLs) on nine chromosomes. Single QTLs explained 9.67% to 16.14% of the observed phenotypic variation. Nine QTLs co-localized with previously reported Yr genes or genomic regions. The remaining QTLs were potentially novel loci and associated with adult-stage stripe-rust resistance. Two novel QTLs, QYr.sicau-3B.2 and QYr.sicau-5B.3, located on chromosomes 3B and 5B significantly explained 16.14% and 11.16% of the phenotypic variation, respectively. Haplotype analysis revealed that accessions carrying APR variants or their combinations showed enhanced degrees of resistance. The potentially novel loci or genomic regions associated with adult-stage resistance may be useful to improve stripe-rust resistance in current wheat cultivars and for future isolation of stripe-rust resistance genes.