DNA and morphological markers for a Russian wheat aphid resistance gene

Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, United States
Euphytica (Impact Factor: 1.39). 01/2004; 139(2):167-172. DOI: 10.1007/s10681-004-2898-4


The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a significant insect pest of wheat worldwide. Morphological and molecular markers associated with RWA resistance could be used to increase the accuracy and efficiency of selection of resistant germplasm and facilitate transfer to desirable wheat genotypes. The objective of this work was to identify microsatellite (SSR) markers linked to the RWA resistance gene (Dn4) and glume-colour gene (Rg2) using a population of F2-derived F3 families originating from a cross between a susceptible line (synthetic hexaploid-11) and a resistance cultivar (Halt). Two microsatellite markers Xgwm106 and Xgwm337 flanked Dn4 on the short arm of chromosome 1D at 5.9 and 9.2 cM, respectively. Two other microsatellite markers, Xpsp2999 and Xpsp3000, at the distal part of this chromosome arm are linked to Dn4 and to Rg2. The accuracy and efficiency of marker-assisted selection were calculated for homozygous Dn4Dn4 genotypes in the F2 generation. The gene Rg2 for red glume colour can also be used for marker-assisted selection of Dn4 gene individually and in combination with microsatellite markers. When used together, the closest markers Xgwm106 and Xgwm337, provide 100% accuracy and 75% efficiency. One hundred percent accuracy is also achieved when the morphological marker red glume is used in combination with either Xgwm106 or Xgwm337. Using these flanking markers, it may be possible to fix resistance to RWA in the first segregating generation of an F2 population without infestation with aphids.

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Available from: Junhua Peng
    • "This strategy was based on fi ndings that all non-rye-derived RWA resistance genes characterized thus far map to the D genome (Liu et al., 2001, 2002, 2005; Ma et al., 1998; Miller et al., 2001). Those SSRs that had been previously linked to RWA resistance genes were included (Arzani et al., 2004 "
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    ABSTRACT: Russian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a significant insect pest of wheat (Triticum aestivum L.) and has had a major economic impact worldwide, especially on winter wheat in the western United States. Development of resistant cultivars remains the most viable method for RWA control, although the continuing emergence of new RWA biotypes virulent to deployed resistance genes reinforces the need for the discovery of new sources of resistance. Iranian wheat landrace accession PI 626580 has shown high levels of resistance to RWA biotypes 1 (RWA1) and 2 (RWA2), but the inheritance and chromosomal location of this resistance is unknown. The objectives of this study were to determine the inheritance of RWA2 resistance, identify closely linked markers, and map the chromosomal location of RWA2 resistance found in PI 626580. Bulked segregant analysis was conducted with a mapping population of 154 F-2 individuals derived from a single plant selection made from PI 626580 and 'Yuma' (a susceptible wheat cultivar). Phenotypic segregation of RWA2 resistance suggested a single dominant gene, provisionally designated Dn626580. Linkage mapping analysis identified three simple sequence repeat (SSR) markers, Xbarc214, Xgwm473, and Xgwm437, proximally linked to Dn626580 near the centromere on the short arm of chromosome 7D at distances of 1.8, 5.0, and 8.2 cM, respectively. Dn626580, a new resistance gene found in PI 626580, could be used alone or by pyramiding with other resistance genes to develop cultivars with effective RWA resistance.
    No preview · Article · Mar 2012 · Crop Science
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    • "Furthermore, the efficiency of SSR markers was also demonstrated for hexaploid wheat, a self-pollinating species with a relatively low level of intraspecific polymorphism (Plaschke et al. 1995; Röder et al. 1995). In recent years, a large number of SSR markers have been developed and extensively utilized in genomic mapping and marker-assisted breeding (Bryan et al. 1997; Röder et al. 1998; Peng et al. 1999, 2000a, b, c, 2003, 2007; Liu et al. 2001; Song et al. 2002; Arzani et al. 2004; Somers et al. 2004;, population genetic analyses (Li et al. 2000a, b) and diversity/polymorphism evaluation of germplasm (Fahima et al. 1998, 2002; Huang et al. 2002; Alamerew et al. 2004; Bertin et al. 2004; Khlestkina et al. 2004a, b; You et al. 2004; Roussel et al. 2004, 2005; Teklu et al. 2006; Zhang et al. 2006; Liu et al. 2007) in wheat. "
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    ABSTRACT: Genetic diversity of a set of 71 wheat accessions, including 53 biotype 2 Russian wheat aphid (RWA2)-resistant landraces and 18 RWA2 susceptible accessions, was assessed by examining molecular variation at multiple microsatellite (SSR) loci. Fifty-one wheat SSR primer pairs were used, 81 SSR loci were determined, and 545 SSR alleles were detected. These SSR loci covered all the three genomes, 21 chromosomes, and at least 41 of the 42 chromosome arms. Diversity values averaged over SSR loci were high with mean number of SSR alleles/locus=6.7, mean Shannon’s index (H)=1.291, and mean Nei’s gene diversity (He)=0.609. The three wheat genomes ranked as A>D>B and the homoeologous groups ranked as 7>3 >1>2>6>5>4 based on the number of alleles per locus. Xgwm136 on chromosome arm 1AS is the most polymorphic SSR locus with the largest number of observed and effective alleles and the highest H and He. Among all 2485 pairs of wheat accessions, genetic distance (GD) ranged from 0.054 to 1.933 and averaged 0.9832. A dendrogram based on GD matrix showed that all the wheat accessions could be grouped into distinct clusters. Most of the susceptible cultivars (13/18) were clustered into groups that contains all or mostly susceptible accessions. Most of the U.S. cultivars belong to a group that is distinguishable from all the different RWA2 resistant groups. Diversity analysis was also conducted separately for subgroups containing 53 RWA2-resistant accessions and 18 RWA2-susceptible accessions. Association mapping revealed 28 SSR loci significantly associated with leaf chlorosis, and 8 with leaf rolling. New chromosome regions associated with RWA2 resistance were detected, and indicated existence of new RWA resistance genes located on chromosomes of all other homoeologous groups in addition to the groups 1 and 7 in bread wheat. This information is helpful for development of mapping populations for RWA2 resistance genes from different phylogenetic groups, and for wise utilization of the RWA-resistant germplasm in wheat breeding programs.
    Full-text · Article · Jan 2009 · Genetica
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    • "To date, most of the RWA-resistant genes have been mapped to group 1 or 7 Triticeae chromosomes (Anderson et al., 2003; Arzani et al., 2004; Lapitan et al., 2007; Liu et al., 2001, 2002, 2005). Thus, we initially tested 23 SSR markers located on group 1 and 7 chromosomes. "
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    ABSTRACT: Russian wheat aphid (RWA) [Diuraphis noxia (Kurdjumov)] is an important pest of wheat (Triticum aestivum L.) in several production areas of the world. The most effective and economical approach for controlling RWA is to use resistant cultivars. A wheat line, ST-ARS 02RWA2414- 11 (2414-11), showed a high level of resistance to RWA biotype 2. Our objectives were to map the resistance gene and develop polymerase chain reaction (PCR)–based markers for markerassisted selection (MAS). A mapping population of 212 F2 individuals was developed from a cross of 2414-11 and the susceptible cultivar Yuma. The F2 individuals and F2:3 families were infested using biotype 2 RWA. The RWA resistance of 2414-11 is controlled by a single major gene, provisionally designated as Dn2414. Using standard PCR, 30 marker loci were found to be linked to Dn2414 with recombination frequencies (θ) of 0.00 to 0.27 and logarithm of the odds to the base 10 (LOD) scores of 7.6 to 66.1. Of the 30 markers, 26 were tightly linked to Dn2414 with θ ≤ 0.05. A genetic map was constructed consisting of 31 loci spanning a region of 34.7 cM. The close linkage of Dn2414 with several rye chromosome 1R short arm (1RS)-specifi c simple sequence repeat markers and low θ values around the Dn2414 gene indicate that Dn2414 is located on chromosome 1RS.1BL (translocation chromosome with IRS and wheat chromosome 1B long arm). Phenotypic and marker profi les of 2414-11 and its relatives are the same as other lines known to carry Dn7. The Dn2414 gene is thus located on 1RS arm, and the large number of PCR markers will be valuable for MAS of this gene.
    Full-text · Article · Jan 2007 · Crop Science
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