Methylation-sensitive amplification polymorphism analysis reveals the DNA methylation dynamics during capitulum development in Chrysanthemum lavandulifolium

Chrysanthemum lavandulifolium (Fischer ex Trautv.) Makino is a diploid plant belonging to the Asteraceae family, with typical capitula composed of female ray florets and bisexual disc florets. The differentiation and development of these two types of florets have long been important research focuses; however, the potential epigenetic mechanisms governing these processes have not been elucidated. In the present study, methylation-sensitive amplification polymorphism method was used to trace the dynamic changes of DNA methylation during capitulum development in C. lavandulifolium. DNA methylation patterns and levels were detected in the whole capitula during seven developmental stages, and the obtained results revealed that DNA demethylation was dominant during this process. In addition, DNA methylation patterns and levels showed significant differences between ray and disc florets. Moreover, the expression patterns of candidate genes potentially involved in the development processes of two types of florets were analyzed by real-time quantitative reverse transcription polymerase chain reaction, and correlation analysis indicated that the expression levels of ClPI, ClAG2, ClSEP1, ClCYC2c, ClCYC2d, and ClCYC2e were highly correlated with DNA methylation levels. These results indicate that DNA methylation may be involved in the differentiation and development of ray and disc florets. This study provides epigenetic insights into the capitulum development in C. lavandulifolium.