MBD protein recognizes flower control genes regulated by DNA methylation in <i>Chrysanthemum lavandulifolium</i>

Abstract

Dynamic changes in DNA methylation regulate the expression of genes and play important roles especially in the flowering processes of higher plants. Methyl-CpG-binding domain protein could specifically recognize hypermethylated regions in the genome, thus MBD sequencing technology and CpG islands analysis of the sequences were used to identify candidate genes that were regulated by DNA methylation, in particular the flowering induction stage of <em>Chrysanthemum lavandulifolium</em>. MBD-seq identified 89 candidate genes which included 49 genes exhibiting changes in DNA methylation status during floral induction. Based on CpG islands analysis of the sequences, 27 candidate genes were selected that may be regulated by DNA methylation. The expression levels of 30 candidate genes and nine key genes were determined by RT-PCR and qRT-PCR during floral induction (7D), four genes (<em>ClFT</em>, <em>ClMET</em>, <em>DFL</em> and <em>ClWRKY21</em>) were similarly up-regulated. Methylation-specific PCR analysis also indicated that there were changes in the DNA methylation status in the <em>DFL</em> and <em>ClWRKY21</em>. The changes in the DNA methylation status during the induction phase of flowering may lead to changes in gene expression. In this study, a set of genes were identified that are proposed to be involved in floral induction and two key genes were identified (<em>DFL, ClWRKY21</em>) that were regulated by DNA methylation during the flowering process of <em>C. lavandulifolium</em>.