DNA Methylation Profile of β-1,3-Glucanase and Chitinase Genes in Flax Shows Specificity Towards Fusarium Oxysporum Strains Differing in Pathogenicity

Most losses in flax ( L.) crops are caused by fungal infections. The new epigenetic approach to improve plant resistance requires broadening the knowledge about the influence of pathogenic and non-pathogenic strains on changes in the profile of DNA methylation. Two contrasting effects on the levels of methylation in flax have been detected for both types of strain infection: Genome-wide hypermethylation and hypomethylation of resistance-related genes ( and ). Despite the differences in methylation profile, the expression of these genes increased. Plants pretreated with the non-pathogenic strain memorize the hypomethylation pattern and then react more efficiently upon pathogen infection. The peak of demethylation correlates with the alteration in gene expression induced by the non-pathogenic strain. In the case of pathogen infection, the expression peak lags behind the gene demethylation. Dynamic changes in tetramer methylation induced by both pathogenic and non-pathogenic strains are dependent on the ratio between the level of methyltransferase and demethylase gene expression. Infection with both strains suppressed methyltransferase expression and increased the demethylase ( ) transcript level. The obtained results provide important new information about changes in methylation profile and thus expression regulation of pathogenesis-related genes in the flax plant response to stressors.