Effects of TDZ and IBA on DNA methylation during callus induction in pear (<i>Pyrus ussuriensis</i> Maxim)

Abstract

One of the essential epigenetic processes in higher eukaryotes, DNA methylation is essential for maintaining genome integrity and influencing gene expression. There aren't many research on how plant growth regulators (PGR) affect DNA methylation during the pear callus formation process. In this work, By using methylation-sensitive amplification polymorphism (MSAP), DNA methylation in pear callus caused by various quantities of thidiazuron (TDZ) and indole-3-butyric acid (IBA) was compared. The concentrations of TDZ and IBA could affect the callus induction rate and methylation level. It was discovered that induction rate and methylation were negatively correlated. The rate of pear callus induction was highest (54%) while the medium suppled with 3.0 mg·L^-1 TDZ and 4.0 mg·L^-1 IBA, although the matching DNA methylation level was lowest (27.96%). Additionally, there were significant difference in th level of genes' expression between different treatments and Both methylation and demethylation are regulated by these genes. As for genes related to auxin and cytokinin, gene expression analysis revealed that their levels of expression after different concentrations of TDZ combined with IBA present in differences significantly. Our findings provide light on DNA methylation mechanisms of plant tissue culture (PTC) dedifferentiation.