Centromere structure and function analysis in wheat–rye translocation lines

Summary 1 RS .1 BL translocations are centric translocations formed by misdivision and have been used extensively in wheat breeding. However, the role that the centromere plays in the formation of 1 RS .1 BL translocations is still unclear. Fluorescence in situ hybridization ( FISH ) was applied to detect the fine structures of the centromeres in 130 1 RS .1 BL translocation cultivars. Immuno‐ FISH , chromatin immunoprecipitation (Ch IP )‐ qPCR and RT ‐ PCR were used to investigate the functions of the hybrid centromeres in 1 RS .1 BL translocations. New 1R translocations with different centromere structures were created by misdivision and pollen irradiation to elucidate the role that the centromere plays in the formation of 1 RS .1 BL translocations. We found that all of the 1 RS .1 BL translocations detected contained hybrid centromeres and that wheat‐derived CENH 3 bound to both the wheat and rye centromeres in the 1 RS .1 BL translocation chromosomes. Moreover, a rye centromere‐specific retrotransposon was actively transcribed in 1 RS .1 BL translocations. The frequencies of new 1 RS hybrid centromere translocations and group‐1 chromosome translocations were higher during 1R misdivision. Our study demonstrates the hybrid nature of the centromere in 1 RS .1 BL translocations. New 1R translocations with different centromere structures were created to help understand the fusion centromere used for wheat breeding and for use as breeding material for the improvement of wheat.