A Novel Wheat-<b><i>Dasypyrum breviaristatum </i></b>Substitution Line with Stripe Rust Resistance

Abstract

The introduction of genetic variation from wild and cultivated Triticeae species has been a long-standing approach for wheat improvement. Dasypyrumbreviaristatum species harbor novel and agronomically important genes for resistance against multi-fungal diseases. The development of new wheat-D. breviaristatum introgression lines offers chances for the identification of stripe rust resistance gene(s). A wheat line, D11-5, was selected from a cross between wheat line MY11 and wheat-D. breviaristatum partial amphiploid TDH-2. It was characterized by FISH and PCR-based molecular markers. Chromosome counting revealed that the D11-5 line shows a hexaploid set of 2n = 6x = 42 chromosomes. FISH analysis using the Dasypyrum repetitive sequence pDb12H as a probe demonstrated that D11-5 contained a pair of D. breviaristatum chromosomes, while FISH with wheat D-genomic repetitive sequences revealed that the chromosome 2D was absent in D11-5. The functional molecular markers confirmed that the introduced D. breviaristatum chromosomes belong to the homoeologous group 2, indicating that D11-5 was a 2V^b (2D) disomic substitution line. Field resistance showed that the introduced D. breviaristatum chromosomes 2V^b were responsible for the stripe rust resistance at the adult plant stage. FISH, C-banding, and PCR-based molecular marker analysis indicated that the chromosome 2V^b of D. breviaristatum was completely different from the chromosome 2V of D. villosum. The identified wheat-D. breviaristatum chromosome substitution line D11-5 may be applied to produce agronomically desirable stripe rust resistance germplasm.

Characterization of New Wheat-<b><i>Dasypyrum breviaristatum</i></b> Introgression Lines with Superior Gene(s) for Spike Length and Stripe Rust Resistance

“…Both wheat and D. breviaristatum chromosomes can be easily distinguished based on the previously published work of Li et al [2016]. The D. breviaristatum chromosomes in a wheat background can also be identified by FISH using the Dasypyrum -specific LTR probe pDb12H [Yang et al, 2006;Li et al, 2014]. As shown in Figure 1 b .…”

“…The wheat cultivar Mianyang11 (MY11), wheat-D. breviaristatum partial amphiploid TDH-2 [Yang et al, 2005], and wheat-D. breviaristatum 2V b (2D) disomic substitution line D11-5, a BC 1 F 4 from the crosses between MY11 and TDH-2 [Li et al, 2014], were maintained in our laboratory at the University of Electronic Science and Technology of China. The wheat line Chinese spring (CS) and the nulli-tetrasomic (NT) lines of CS [Sears, 1966] were obtained from Dr. Bernd Friebe, Kansas State University, USA.…”

“…DNA was extracted from young leaves of CS, Taichang 29, TDH-2, D11-5, and 2V b -derived lines following the method of Li et al [2014]. PCR-based landmark unique gene (PLUG) primers were designed according to Ishikawa et al [2009].…”

“…Cytological and molecular evidence suggested the occurrence of significant genomic diversification between the 2 Dasypyrum species [De Pace et al, 2011;Baum et al, 2014;Li et al, 2016], and research has been conducted with the aim to transfer useful genes from D. breviaristatum into wheat. Subsequently, the wheat-D. breviaristatum partial amphiploid [Yang et al, 2005] and wheat-D. breviaristatum introgression lines with multiple disease resistances were developed [Li et al, 2014[Li et al, , 2016.…”

“…A previously described wheat-D. breviaristatum 2V b (2D) substitution line, named D11-5, displayed high resistance to stripe rust and good agronomic traits, which apparently were located on the Dasypyrum chromosome [Li et al, 2014]. To localize these elite genes on the chromosome 2V b , it was necessary to produce and precisely characterize wheat-D. breviaristatum 2V b small segment deletion mutants or translocation lines.…”