French marigold essential oil affected DNA methylation in potato

Abstract

Different stressors from the environment can prime defense and enable enhanced responses to subsequent stress exposure. It has been proposed that induced epigenetic changes, on the level of DNA and histones, could be involved in this response. Plant essential oils (EOs) have shown promising prospects as novel priming inducers. Still, little is known about their potential to induce epigenetic alternations. In this study, we examined the effect of the French marigold (Tagetes patula L.) EO on DNA methylation of potato (Solanum tuberosum L.). Potato plants were exposed to EO for 3 consecutive days for 8h each day, and samples were collected 10 days after EO removal. Whole-Genome Bisulfite Sequencing (WGBS) was used to identify differentially methylated (DM) DNA sequences among control and EO-exposed samples. Promoters, exons, introns, 3‘UTR, 5‘UTR, and intergenic regions, each at a differential methylation ratio 0.1 to 0.25 between control and treated samples were analyzed. The average methylation level of the whole genome was 72.29% and 69.23% in control and exposed samples, respectively. Differential DNA methylation has predominantly occurred in the CG context compared to CHH and CHG. In general, hypomethylated sequences outnumbered hypermethylated ones. Functional annotation clustering of differentially methylated genes distinguished 6 affected KEGG pathways – endocytosis (sot04144) and protein processing in the endoplasmatic reticulum (sot04141) among others. The expression of DM genes associated with these pathways, as well as different defense responses in potato (GO:0006952), will be analyzed subsequently in potato plants challenged with different abiotic and biotic stress conditions.