Chromosome aberrations induced by zebularine in triticale.

Chromosome engineering is an important approach for generating wheat germplasm. Efficient development of chromosome aberrations will facilitate the introgression and application of alien genes in wheat. In this study, zebularine, a DNA methylation transferase inhibitor, was successfully used to induce chromosome aberrations in the octoploid triticale cultivar Jinghui#1. Dry seeds were soaked in zebularine solutions (250, 500, and 750 μmol/L) for 24 h, and the 500 μmol/L treatment was tested in three additional treatment times, i.e., 12, 36, and 48 h. All treatments induced aberrations involving wheat and rye chromosomes. Of the 920 cells observed in 67 M1 plants, 340 (37.0%) carried 817 aberrations with an average of 0.89 aberrations per cell (range: 0-12). The aberrations included probable deletions, telosomes and acentric fragments (49.0%), large segmental translocations (28.9%), small segmental translocations (17.1%), intercalary translocations (2.6%), long chromosomes that could carry more than one centromere (2.0%), and ring chromosomes (0.5%). Of 510 M2 plants analyzed, 110 (21.6%) were found to carry stable aberrations. Such aberrations included 79 with varied rye chromosome numbers, 7 with wheat and rye chromosome translocations, 15 with possible rye telosomes/deletions, and 9 with complex aberrations involving variation in rye chromosome number and wheat-rye translocations. These indicated that aberrations induced by zebularine can be steadily transmitted, suggesting that zebularine is a new efficient agent for chromosome manipulation.