Molecular characterization of a cryptic wheat-Thinopyrum intermedium translocation line: evidence for genomic instability in nascent allopolyploid and aneuploid lines

A putative translocation line (#32), together with a disomic addition line (TAI27) and an octo-amphiploid line (Zhong3) of common wheat and Thinopyrum intermedium were characterized by restriction fragment length polymorphism (RFLP) analysis, using probes covering all seven homoeologous groups of Triticeae. Line 32 was confirmed to be a cryptic translocation line, based on the detection of multiple introgressed hybridization fragments specific to Th. intermedium in the RFLP patterns, and the absence of a hybridization signal in GISH analysis. In addition, extensive genomic changes, as compared to the wheat parent, were detected on all three lines studied, with a great majority of changes showing concordance among the lines. Our data is consistent with the emerging view that nascent allopolyploid and aneuploid plant genomes are highly dynamic, which may generate novel introgressed materials for breeding.