Methylome changes during Lr48-mediated APR for leaf rust in wheat (Triticum aestivum L.)

Differential DNA methylation due to APR gene Lr48 for leaf rust resistance in wheat cv. CSP44 was examined at pre-adult plant (P-AP) susceptible stage and adult plant (AP) resistant stage. As many as 52,872 differentially methylated regions (DMRs) carrying 897 differentially methylated genes (DMGs) and many intergenic regions were identified. A proportion of individual DMGs involved in methylation included exons/introns, promoters and UTRs. DMGs were also compared with transcriptome data based on RNA-seq. Susceptibility (at P-AP) was found to be governed by activation (due to hypomethylation) of relatively more genes, whereas resistance (at AP) involved silencing of relatively large number of genes. Using GO terms, DMGs were assigned to a variety of functions belonging to biological processes including transcription regulation, protein synthesis, signal transduction, defense, photosynthesis, lipid and carbohydrate metabolism. The results of the present study improved our understanding of the epigenetic control of APR to leaf rust in wheat.