Analysis of DNA methylation variation in sibling tobacco (Nicotiana tabacum) cultivars
Amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP) analysis were used to investigate the genome of two sibling tobacco cultivars, Yunyan85 and Yunyan87, their parent K326 and the other tobacco cultivar NC89. AFLP analysis indicated that, the genome primary structure variations were not obviously detected among Yunyan85 and Yunyan87 and K326. However, the methylation extent had different alteration between the sibling tobacco cultivars relative to their parent; it rose to 42.97 and 36.55% in Yunyan85 and Yunyan87, respectively. Both the full and semi-methylation modifications on the ‘CCGG/GGCC’ site were significantly increased in Yunyan85 and Yunyan87, however, the full-methylation modification on the ‘CCGG/GGCC’ site in Yunyan85 was significantly higher than the one in Yunyan87. Among the polymorphic methylated sites, most of them (53.70%) were hypermethylation sites, 35 (16.20%) sites were demethylation modification and 62 (28.70%) sites were uncertain methylation modification. The sequences involved in methylation alteration mainly included promoter regions. The results in this study have provided a better understanding of gene expression phenotype.
Key words: Nicotiana tabacum, methylation, amplified fragment length polymorphism (AFLP), methylationsensitive amplification polymorphism (MSAP).