Comparison of DNA methylation in developing seeds of Ricinus communis L. using MSAP analysis

DNA methylation plays an important role in endosperm development and is involved in the epigenetic regulation of gene expression. However, the epigenetic regulation of castor seed development has not yet been reported. In this study, methylation-sensitive amplification polymorphism (MSAP) analysis was used to investigate the methylation level in castor. In 20-day-old castor seeds, 41.17% of the fragments were fully methylated and 15.61% were hemimethylated. In 60 day-old seed, the full methylation and hemimethylation rates were 19.77% and 7.56%, respectively, suggesting that some methylation level changes existed during the castor seed development. A total of 647 bands were identified with different methylation or demethylation patterns during the seed maturation. However, only 37 sequences were homologous to well-known proteins, such as phospholipid-transporting ATPase, phosphatases and methyltransferase. Therefore, these results clearly demonstrated that the MSAP technique is very useful for the analysis of the global DNA methylation state in castor and the complexity of DNA methylation changes during seed development. The different methylation levels may be correlated with the specific gene expression in different seed development stages.