Characterization of gene Yr79 and four additional QTL for all-stage and high-temperature adult-plant resistance to stripe rust in spring wheat PI 182103

Authors: FENG, JUNYAN - Washington State University; WANG, MEINAN - Washington State University; See, Deven; Chao, Shiaoman; ZHENG, YOULINAG - Sichuan Agricultural University; Chen, Xianming

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2018
Publication Date: 6/20/2018
Citation: Feng, J., Wang, M., See, D.R., Chao, S., Zheng, Y., Chen, X. 2018. Characterization of gene Yr79 and four additional QTL for all-stage and high-temperature adult-plant resistance to stripe rust in spring wheat PI 182103. Theoretical and Applied Genetics. 108(6):737-747.

Interpretive Summary: Stripe rust is an important disease of wheat worldwide. Exploring new resistance genes is essential for breeding resistant wheat cultivars. PI 182103, a spring wheat landrace originally from Pakistan, has shown a high level of resistance to stripe rust in the field for many years. To map the resistance gene(s) in PI 182103, 185 recombinant inbred lines (RILs) were developed from a cross with suscepotible wheat AvS. The tests of seedlings of the RIL population with selected pathogen races and in fields in 2011, 2012 and 2013 showed that the PI 182103 resistance to stripe rust was controlled by QTL. A total of five resistance QTL were detected and mapped to chromosomes. QyrPI182103.wgp-2AS and QyrPI182103.wgp-3AL were detected at the seedling stage, QyrPI182103.wgp-4DL was detected only in Mt. Vernon field tests, and QyrPI182103.wgp-5BS was detected in both seedling and field tests. QyrPI182103.wgp-7BL was identified as a high-temperature adult-plant resistance gene and detected in all field tests. Interactions among the QTL were mostly additive, but some negative interactions were also detected. The 7BL QTL was mapped in chromosomal bin 7BL 0.40-0.45 and identified as a new gene designated Yr79. Tests of polymorphic markers Xbarc72 and Xwmc335 flanking Yr79 in US wheat lines showed that no line had both flanking alleles. Single gene lines selected from the progeny and identified molecular markers will be useful as donors for incorporating the resistance genes into new wheat varieties.

Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of wheat worldwide. Exploring new resistance genes is essential for breeding resistant wheat cultivars. PI 182103, a spring wheat landrace originally from Pakistan, has shown a high level of resistance to stripe rust in the field for many years. To map the resistance gene(s) in PI 182103, 185 recombinant inbred lines (RILs) were developed from a cross with Avocet Susceptible (AvS). The seedlings of the parents and F1 and RILs tested with races PST-100 and PST-114 indicated that the all-stage resistance of PI 182103 was controlled by quantitative trait loci (QTL). In 2011, 2012 and 2013, the parents and RILs were evaluated for stripe rust reaction in randomized complete block experiments in fields at Pullman and Mt. Vernon, Washington under natural infection by the stripe rust pathogen. Both infection type and disease severity-based relative area under the disease progress curve (rAUDPC) data indicated that the PI 182103 resistance to stripe rust observed in fields was controlled by QTL. A total of five QTL were detected using data from greenhouse seedling and adult-plant field tests. QyrPI182103.wgp-2AS and QyrPI182103.wgp-3AL were detected at the seedling stage, QyrPI182103.wgp-4DL was detected only in Mt. Vernon field tests, and QyrPI182103.wgp-5BS was detected in both seedling and field tests. QyrPI182103.wgp-7BL was identified as a high-temperature adult-plant (HTAP) resistance gene and detected in all field tests. Interactions among the QTL were mostly additive, but some negative interactions were also detected. The 7BL QTL was mapped in chromosomal bin 7BL 0.40-0.45 and identified as a new gene designated Yr79. Tests of polymorphic markers Xbarc72 and Xwmc335 flanking Yr80 in various wheat genotypes showed that no line had both flanking alleles. Single gene lines selected from the RILs and identified molecular markers will be useful as donors for incorporating the resistance genes into new wheat cultivars.