Comparative FISH and molecular identification of new stripe rust resistant wheat-Thinopyrum intermedium ssp. trichophorum introgression lines

Abstract

Thinopyrum intermedium (2n = 6x = 42, JJJsJsStSt) has been hybridized extensively with common wheat and has proven to be a valuable germplasm source for improving disease resistance, quality attributes, and yield potential in wheat. We characterized new disease resistant wheat-Th. intermedium derivatives A1082 and A5-5 using sequential multi-color fluorescence in situ hybridization (mc-FISH), genomic in situ hybridization (GISH), PCR-based landmark unique gene (PLUG) and intron targeting (IT) markers. A1082 was identified as a wheat-Th. intermedium 3J disomic addition line, and A5-5 was a T4BS·5JsL homozygous Robertsonian translocation line. Seventy-one and 106 pairs of primers amplified Th. intermedium-specific bands allowing chromosomes 3J and 5Js to be tracked, respectively. A new oligonucleotide probe, Oligo-6H-2-100, was developed for FISH labeling of the subterminal region of the long arm of chromosome 5Js. Both lines were highly resistant to stripe rust pathogen races prevalent in Chinese field screening nurseries. A5-5 also displayed a significant increase in tiller number compared to its wheat parent. The new lines can be exploited as useful germplasms for wheat improvement.