Molecular Cytogenetic Identification of Triticum aestivum-Thinopyrum ponticum 5J(E) Disomic Addition Line with Stripe Rust Resistance and Salt Tolerance
Abstract：Thinopyrum ponticum (2n=10x=70), which contains excellent resistance and stress tolerance genes to against biotic and abiotic stress, is an important germplasm for wheat (Triticum aestivum) improvement. The development of novel Tr. aestivum (common wheat)-Th. ponticum derivatives will provide valuable germplasm to wheat resistance breeding programs. CH1115-B15-1-5-1-1 (CH1115-B15), a novel disomic addition line from the cross of 7182 (Tr. aestivum)/Th. ponticum//87-1-9 (Tr. aestivum), was characterized by cytological identification, morphological analysis, salt tolerance analysis, genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) analysis, simple sequence repeat (SSR), expressed sequence tag (EST) and PCR based landmark unique gene (PLUG) markers analysis. Cytological observations showed that CH1115-B15 contained 44 chromosomes and formed 22 bivalents at meiotic metaphase Ⅰ and the addition line was stable in morphology and cytology. GISH and FISH analysis suggested that, of 44 line chromosomes, 42 chromosomes were common with wheat chromosomes, and 2 chromosomes came from Th. ponticum chromosomes. In addition, the pair of alien chromosomes carried on similar Oligo-pTa535 signals. GISH analysis showed that the pair of alien chromosomes belonged to the genome J(E). The polymorphic analysis with 2 SSR markers, 4 EST markers, and 4 PLUG markers showed that the pair of alien chromosome belonged to the fifth homeologous group. Salt tolerance analysis at the germination stage and evaluation of adult stripe rust resistance showed that line had high resistance to wheat stripe rust (IT=1) at the adult stage and excellent salt tolerance at the germination stage. Therefore, CH1115-B15 is Tr. aestivum- Th. ponticum 5J(E) disomic addition line with excellent stripe rust resistance and salt tolerance, and it could be exploited as a promising germplasm in wheat breeding and chromosome engineering.
