Effects of the cytidine analogue zebularine on wheat mitotic chromosomes

Zebular ine, c yt idine analog is known as DNA methylation inhibitor such as 5-azacytidine and 5-aza2’-deoxycytidine, and it is more stable in aqueous solution than 5-azacytidine and 5-aza-2’-deoxycytidine. We investigated effects of zebularine on plant mitotic chromosomes. A wheat disomic addition line carrying a pair of alien chromosomes (Leymus racemosus chromosome l) was treated with zebularine at various concentrations. The alien chromosomes were discriminated from the wheat chromosomes by genomic in situ hybridization, facilitating observation of any rearrangements between the wheat and alien chromosomes. Root growth was obviously inhibited by zebularine because of reduction of the mitotic division cells. Rearrangements such as ring chromosomes, insertions, deletions, and translocations were observed in the treated mitotic chromosomes. The aberrations were increased in a concentration-dependent manner of zebularine.