ANALYSIS OF DNA METHYLATION OF Spirodela polyrhiza (GRATER DUCKWEED) IN RESPONSE TO ABSCISIC ACID USING METHYLATION-SENSITlVE AMPLIFIED POLYMORPHISM1

摘要

Spirodela polyrhiza is an a energy feedstock, which can produce a kind of dormant fronds called turions to survive cold. ABA can induce S. polyrhiza to form turions and is the most important hormone for plants to resist abiotic stresses. DNA methylation plays an important role in plant development by regulating gene expression. In this study, we studied DNA methylation variation in the fronds of S. polyrhiza treated with ABA and compared DNA methylation variation between fronds and turions, using themethylation-sensitive amplified polymorphism procedure. We selected 60 pairs of selective amplification primers to assess the status and levels of cytosine methylation. The results showed that ABA triggered the hemimethylation or internally full methylation of cytosine. With the prolongation of ABA treatment, the methylation of the total DNA increased. The alteration analysis of cytosine methylation showed that the number of demethylation events were much lower than those of methylation, which indicates that methylation was predominant. In addition, the methylation level in turions was higher than in the fronds. Moreover, the sequences of 14 differentially amplified DNA fragments were analyzed. According to Blast analysis, most of the 14 fragments were identified as genes or DNA involved in the abiotic stress response. The fragment M11 is homologous to ATPase. ABA may affect the methylation status of ATPase gene to regulate its expression to resist chilling. Our study showed that ABA might affect gene expression via changing the methylation status of the cytosine nucleotide.