Development and molecular cytogenetic identification of a new wheat-Psathyrostachys huashanica Keng translocation line with resistances to stripe rust

Psathyrostachys huashanica Keng (2n = 14, NsNs), a wild relative of common wheat, is an excellent gene source for wheat improvement because of its strong disease resistance, drought tolerance, and high tillering capacity. In this study, one additional line E3-6-4 (2n=44) and E3-6-4 with high resistance to stripe rust were used in the hybrid progeny of common wheat parent 7182 and Psathyrostachys huashanica Keng, and the BC1F3 offspring of the wheat parent 7182 were used as research objects. We revealed nine distinct chromosome composition types through Genome in situ hybridization analysis. Among these, two homozygous translocation lines were identified: 2L (2n = 42) and 2S# (2n = 44). Fluorescence in situ hybridization analysis, together with expressed sequence tagsequence-tagged site markers, simple sequence repeats, and a wheat liquid-phase microarray, revealed that 2L carries a 3DS3DL-2NsL translocation. Similarly, the 2S# type was identified as 3DL2NsL-2NsS. Results of the 55K single-nucleotide polymorphism microarray analysis indicated that the translocation breakpoints were located between 445.63 and 451.69 Mb on wheat chromosome 3DL. The translocation line 3DS3DL-2NsL demonstrated superior performance and stronger resistance to stripe rust than 7182, whereas 3DL2NsL-2NsS showed characteristics more similar to E3-6-4 but was moderately susceptible. Overall, the results of this study suggest that the 2Ns chromosome of P. huashanica carries the stripe rust resistance gene, which is located on the 2NsL fragment in the 3DS3DL-2NsL translocation line. This line represents a novel parental material for enhancing wheat resistance to stripe rust and improving yield.