New slow-rusting leaf rust and stripe rust resistance genes Lr67 and Yr46 in wheat are pleiotropic or closely linked (original) (raw)
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Lr46 : A Gene Conferring Slow-Rusting Resistance to Leaf Rust in Wheat
Phytopathology, 1998
Wheat (Triticum aestivum) cultivar Pavon 76 carries slow-rusting resistance to leaf rust that has remained effective in Mexico since its release in 1976. ‘Pavon 76’ was crossed with two leaf rust-susceptible wheat cultivars, Jupateco 73S and Avocet S, and between 118 and 148 individual F2 plant-derived F3 and F5 lines were evaluated for adult-plant leaf rust resistance at two field sites in Mexico during different seasons. Evaluation of F1 plants and parents indicated that the slow-rusting resistance was partially dominant. Segregation in the F3 and F5 indicated that the resistance was based on two genes with additive effects. Monosomic analysis was carried out to determine the chromosomal locations of the resistance genes. For this purpose, two or three backcross-derived cytogenetic populations were developed by crossing ‘Pavon 76’ with a monosomic series of adult-plant leaf rust-susceptible cultivar Lal-bahadur. Evaluation of such BC2F3 and BC3F3 lines from 16 confirmed ‘Lalbahadu...
Theoretical and Applied Genetics, 2010
Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identiWed in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for Wrst meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through Wve cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher £ RL6077 and RL6058 (Thatcher*6/PI58548) £ RL6077 showed highly signiWcant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in Weld trials showed no eVect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67.
Journal of Genetics, 2016
A pair of stripe rust and leaf rust resistance genes was introgressed from Aegilops caudata, a nonprogenitor diploid species with the CC genome, to cultivated wheat. Inheritance and genetic mapping of stripe rust resistance gene in backcrossrecombinant inbred line (BC-RIL) population derived from the cross of a wheat-Ae. caudata introgression line (IL) T291-2(pau16060) with wheat cv. PBW343 is reported here. Segregation of BC-RILs for stripe rust resistance depicted a single major gene conditioning adult plant resistance (APR) with stripe rust reaction varying from TR-20MS in resistant RILs signifying the presence of some minor genes as well. Genetic association with leaf rust resistance revealed that two genes are located at a recombination distance of 13%. IL T291-2 had earlier been reported to carry introgressions on wheat chromosomes 2D, 3D, 4D, 5D, 6D and 7D. Genetic mapping indicated the introgression of stripe rust resistance gene on wheat chromosome 5DS in the region carrying leaf rust resistance gene LrAc, but as an independent introgression. Simple sequence repeat (SSR) and sequence-tagged site (STS) markers designed from the survey sequence data of 5DS enriched the target region harbouring stripe and leaf rust resistance genes. Stripe rust resistance locus, temporarily designated as YrAc, mapped at the distal most end of 5DS linked with a group of four colocated SSRs and two resistance gene analogue (RGA)-STS markers at a distance of 5.3 cM. LrAc mapped at a distance of 9.0 cM from the YrAc and at 2.8 cM from RGA-STS marker Ta5DS_2737450, YrAc and LrAc appear to be the candidate genes for marker-assisted enrichment of the wheat gene pool for rust resistance.
Theoretical and Applied Genetics, 2012
Leaf rust and stripe rust are important diseases of wheat worldwide and deployment of cultivars with genetic resistance is an effective and environmentally sound control method. The use of minor, additive genes conferring adult plant resistance (APR) has been shown to provide resistance that is durable. The wheat cultivar 'Pastor' originated from the CIMMYT breeding program that focuses on minor gene-based APR to both diseases by selecting and advancing generations alternately under leaf rust and stripe rust pressures. As a consequence, Pastor has good resistance to both rusts and was used as the resistant parent to develop a mapping population by crossing with the susceptible 'Avocet'. All 148 F 5 recombinant inbred lines were evaluated under artificially inoculated epidemic environments for leaf rust (3 environments) and stripe rust (4 environments, 2 of which represent two evaluation dates in final year due to the late build-up of a new race virulent to Yr31) in Mexico. Map construction and QTL analysis were completed with 223 polymorphic markers on 84 randomly selected lines in the population. Pastor contributed Yr31, a moderately effective race-specific gene for stripe rust resistance, which was overcome during this study, and this was clearly shown in the statistical analysis. Linked or pleiotropic chromosomal regions contributing to resistance against both pathogens included Lr46/Yr29 on 1BL, the Yr31 region on 2BS, and additional minor genes on 5A, 6B and 7BL. Other minor genes for leaf rust resistance were located on 1B, 2A and 2D and for stripe rust on 1AL, 1B, 3A, 3B, 4D, 6A, 7AS and 7AL. The 1AL, 1BS and 7AL QTLs are in regions that were not identified previously as having QTLs for stripe rust resistance. The development of uniform and severe epidemics facilitated excellent phenotyping, and when combined with multienvironment analysis, resulted in the relatively large number of QTLs identified in this study. Communicated by B. Keller.
Theoretical and Applied Genetics, 2008
Rust diseases are a major cause of yield loss in wheat worldwide, and are often controlled through the incorporation of resistance genes using conventional phenotypic selection methods. Slow-rusting resistance genes are expressed quantitatively and are typically small in genetic effect thereby requiring multiple genes to provide adequate protection against pathogens. These effects are valuable and are generally considered to confer durable resistance. Therefore an understanding of the chromosomal locations of such genes and their biological effects are important in order to ensure they are suitably deployed in elite germplasm. Attila is an important wheat grown throughout the world and is used as a slow-rusting donor in international spring wheat breeding programs. This study identified chromosomal regions associated with leaf rust and stripe rust resistances in a cross between Attila and a susceptible parent, Avocet-S, evaluated over 3 years in the field. Genotypic variation for both rusts was large and repeatable with line-mean heritabilities of 94% for leaf rust resistance and 87% for stripe rust. Three loci, including Lr46/Yr29 on chromosome 1BL, were shown to provide resistance to leaf rust whereas six loci with small effects conferred stripe rust resistance, with a seventh locus having an effect only by epistasis. Disease scoring over three different years enabled inferences to be made relating to stripe rust pathogen strains that predominated in different years.
Frontiers in Plant Science, 2017
Growing resistant wheat varieties is a key method of minimizing the extent of yield losses caused by the globally important wheat leaf rust (LR) and stripe rust (YR) diseases. In this study, a population of 186 F 8 recombinant inbred lines (RILs) derived from a cross between a synthetic wheat derivative (PI610750) and an adapted common wheat line (cv. "UC1110") were phenotyped for LR and YR response at both seedling and adult plant stages over multiple seasons. Using a genetic linkage map consisting of single sequence repeats and diversity arrays technology markers, in combination with inclusive composite interval mapping analysis, we detected a new LR adult plant resistance (APR) locus, QLr.cim-2DS, contributed by UC1110. One co-located resistance locus to both rusts, QLr.cim-3DC/QYr.cim-3DC, and the known seedling resistance gene Lr26 were also mapped. QLr.cim-2DS and QLr.cim-3DC showed a marginally significant interaction for LR resistance in the adult plant stage. In addition, two previously reported YR APR loci, QYr.ucw-3BS and Yr48, were found to exhibit stable performances in rust environments in both Mexico and the United States and showed a highly significant interaction in the field. Yr48 was also observed to confer intermediate seedling resistance against Mexican YR races, thus suggesting it should be reclassified as an allstage resistance gene. We also identified 5 and 2 RILs that possessed all detected YR and LR resistance loci, respectively. With the closely linked molecular markers reported here, these RILs could be used as donors for multiple resistance loci to both rusts in wheat breeding programs.
MappingYr28and Other Genes for Resistance to Stripe Rust in Wheat
Crop Science, 2000
partial control which is unsatisfactory under high disease pressure. Consequently, both are best combined with Stripe (yellow) rust, caused by Puccinia striiformis West., is an other slow-rusting genes (Ma and Singh, 1996; Singh important constraint to wheat production in cool environments. With the purpose of identifying genes for resistance to the disease, a RFLP and Huerta-Espino, 1997). mapping population of recombinant inbred lines developed from Identification and characterization of minor slowa synthetic [Triticum turgidum L. ϫ Aegilops tauschii (Coss.) rusting resistance genes is difficult by classical methods. Schmal.] ϫ T. aestivum L. cv. 'Opata 85' cross was visually evaluated Recently, RFLP maps of wheat chromosomes were confor seedling infection type in three greenhouse inoculation tests and structed (Van Deynze et al., 1995; Nelson et al., 1995a, for adult-plant disease severity in four field tests at Celaya and Toluca, b, c; Marino et al., 1996) in a population of recombinant Mexico. A previously unidentified gene from Ae. tauschii, designated inbred lines (RILs) developed from a synthetic as Yr28, was located on chromosome arm 4DS. Although Yr28 hexaploid ϫ bread-wheat cross. This genetic material strongly influenced seedling resistance, it showed a strong effect in has been used to characterize and map resistance genes adult plants at only the warmer of the two field sites. A second gene for other diseases (Nelson et al., 1995b, 1997, 1998; Faris showed high environmental sensitivity in seedling tests, with resistance associated with Opata marker alleles near the adult-plant resistance et al., 1997). The synthetic parent was reported to carry (APR) gene Yr18 on chromosome arm 7DS. Gene Yr18, known to YR resistance (Ma et al., 1995) and should be a source be present in Opata, strongly reduced disease response in field trials of valuable genetic diversity for bread wheat cultivar imand was tightly linked with leaf-rust resistance gene Lr34. Three other provement. regions from Opata on chromosome arms 3BS, 3DS, and 5DS were The objective of this study was to identify wheat chroalso associated with APR. mosomal regions carrying stripe rust resistance genes effective at seedling and adult-plant stages by using the available mapping population and RFLP map.
Phytopathology, 2003
William, M., Singh, R. P., Huerta-Espino, J., Ortiz Islas, S., and Hoisington, D. 2003. Molecular marker mapping of leaf rust resistance gene Lr46 and its association with stripe rust resistance gene Yr29 in wheat. Phytopathology 93:153-159.
A novel adult plant leaf rust resistance gene Lr2K38 mapped on wheat chromosome 1AL
The Plant Genome, 2020
Soft red winter wheat (SRWW) cultivar AGS 2038 has a high level of seedling and adult plant leaf rust (LR) resistance. To map and characterize LR resistance in AGS 2038, a recombinant inbred line (RIL) population consisting of 225 lines was developed from a cross between AGS 2038 and moderately resistant line UGA 111729. The parents and RIL population were phenotyped for LR response in three field environments at Plains and Griffin, GA, in the 2017–2018 and 2018–2019 growing seasons, one greenhouse environment at the adult‐plant stage, and at seedling stage. The RIL population was genotyped with the Illumina iSelect 90K SNP marker array, and a total of 7667 polymorphic markers representing 1513 unique loci were used to construct a linkage map. Quantitative trait loci (QTL) analysis detected six QTL, QLr.ags‐1AL, QLr.ags‐2AS, QLr.ags‐2BS1, QLr.ags‐2BS2, QLr.ags‐2BS3, and QLr.ags‐2DS, for seedling and adult plant LR resistance. Of these, the major adult plant leaf rust resistance QTL,...