Molecular cytogenetic identification of a wheat (Triticum aestivum)-American dune grass (Leymus mollis) translocation line resistant to stripe rust

Abstract

ABSTRACT. Leymus mollis, a perennial allotetraploid (2n = 4x = 28), known as American dune grass, is a wild relative of wheat that could be useful for cultivar improvement. Shannong0096, developed from interspecific hybridization between common wheat cv. Yannong15 and L. mollis, was analyzed with cytological procedures, genomic in situ hybridization, stripe-rust resistance screening and molecular marker analysis. We found that Shannong0096 has 42 chromosomes in the root-tip cells at mitotic metaphase and 21 bivalents in the pollen mother cells at meiotic metaphase I, demonstrating cytogenetic stability. Genomic in situ hybridization probed with total genomic DNA from L. mollis gave strong hybridization signals in the distal ©FUNPEC-RP www.funpecrp.com.br Identification of a wheat-Leymus mollis translocation Genetics and Molecular Research 11 (3): 3198-3206 (2012) 3199region of two wheat chromosome arms. A single dominant Yr gene, derived from L. mollis and temporarily designated as YrSn0096, was found on the long arm of chromosome 4A of Shannong0096. YrSn0096 should be a novel Yr gene because none of the previously reported Yr genes on chromosome 4A are related to L. mollis. This gene was found to be closely linked to the loci Xbarc236 and Xksum134 with genetic distances of 5.0 and 4.8 cM, respectively. Based on data from 267 F 2 plants of Yannong15/Huixianhong, the linkage map of YrSn0096, using the two molecular markers, was established in the order Xbarc236-YrSn0096-Xksum134. Shannong0096 appeared to be a unique wheat-L. mollis translocation with cryptic alien introgression. Cytogenetic stability, a high level of stripe-rust resistance, the common wheat background, and other positive agronomic traits make it a desirable donor for introducing novel alien resistance genes in wheat breeding programs, with the advantage of molecular markers that can be used to confirm introgression.

Chromosome constitution and origin analysis in three derivatives of Triticum aestivum – Leymus mollis by molecular cytogenetic identification

“…In this study, we examined the disease resistance of three derivatives with different chromosomes: M47, M42, and M51. In previous studies, several common wheat -L. mollis translocation materials resistant to stripe rust were obtained, which were separately located on wheat chromosomes 2AS, 4AL, 5AS, and 7DL related to L. mollis (Song et al 2008;Bao et al 2012). …”

“…Leymus mollis has been used extensively for hybridization with bread wheat and durum wheat, and numerous useful genes, particularly those for stripe rust resistance and drought stress tolerance, have been successfully transferred into wheat (Anamthawat-Jónsson et al 1997;Zhou et al 2001;Lu et al 2005;Shao et al 2007;Song et al 2008;Wang et al 2008;Wang and Wang 2009;Yang et al 2010;Bao et al 2012;Habora et al 2012). Many derivatives have been produced from Triticum aestivum (common wheat) -L. mollis hybrids, such as octoploid amphiploids, hexaploid amphiploids, and an alien substitution line (Fu et al 1993;Wang et al 2000Wang et al , 2013Forsström and Merker 2001;He et al 2010;Yang et al 2010;Zhao et al 2012;Pang et al 2014).…”

Molecular Cytogenetic and Morphological Identification of a Wheat–L. mollis 1Ns(1D) Substitution Line, DM45

“…Using embryo rescue and colchicine treatment, Fu et al (1993) developed different types of octoploid Tritileymus M842 (2n = 56) by successive backcrossing, which exhibited extreme agronomic traits, i.e., long spikes with many florets, big seeds, and tolerance of cold and drought, where Wang et al (2000) indicated that there were two different genome compositions of AABBDDNsNs and AABBDDXmXm according to cytogenetic analysis. Subsequently, several wheat alien germplasms, including addition, substitution, and translocation lines, were obtained by crossing octoploid Tritileymus with wheat cultivars (Fu et al 1996(Fu et al , 1997Bao et al 2012). In order to further exploit and improve the characteristics of octoploid Tritileymus M842, a triple substitution line (05DM6) was generated from the progeny of M842-12 and Triticum durum cv.…”

Molecular Cytogenetic Characterization of Novel Wheat-rye T1RS.1BL Translocation Lines with High Resistance to Diseases and Great Agronomic Traits

“…(Marais et al, 2009; Kuraparthy et al, 2009; Petersen et al, 2015), Pm40 and Yr50 from Thinopyrum spp. (Luo et al, 2009; Liu et al, 2013), Pm21 from Haynaldia villosa (Chen et al, 1995), YrSn0096 from Leymus mollis (Bao et al, 2012), and Pm2b from Agropyron (Ma et al, 2015). However, rye ( Secale cereal L.) is the most important and valuable related species for the improvement of wheat genetics (Schlegel and Korzun, 1997; Rabinovich, 1998; Lelley et al, 2004; Ren et al, 2012).…”