科研之友
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摘要
Interspecific hybridization is associated with the origin of novel traits and confers increased vigor compared with the parent lines, although its molecular basis is poorly understood. We report here the identification of genetic and epigenetic changes in a set of wheat-rye translocation lines (R59, R57, and R25) which exhibited novel heritable morphological characteristics compared with the parent lines (MY11 and L155). Genome in situ hybridization and amplified fragment length polymorphism analyses revealed no obvious variations in the primary structure of the genome in different translocation lines, with the exception of the same 1RS chromosome translocation. Global assessment of the extent and pattern of cytosine methylation alterations by methylation-sensitive amplified polymorphism (MSAP) analyses revealed differences in the extent of genomic DNA methylation between the rye and wheat parent lines. Fully-methylated sites were significantly increased and hemi-methylated sites were markedly decreased in the genome of translocation lines compared with the wheat parental cultivar MY11. Comparisons of different MSAP patterns revealed both monomorphic and polymorphic sites between translocation lines and wheat parents. Sequencing of 44 isolated fragments that showed methylation alterations indicated that cellular genes and especially transposable elements were targets for methylation alterations in translocation lines. The present study provides further understanding of the rules governing the distribution and existence of DNA methylation variations induced in the wheat genome during alien germplasm introduction. Furthermore, our study provides insights into the relationship between DNA methylation and hybrid vigor as well as a theoretical basis for further fundamental research and breeding application.
