Senior researcher Norwegian Institute for Bioeconomy Research Ås, Akershus, Norway
Our goal is to improve the understanding of how epigenetic mechanisms shape phenotypic plasticity and evolution of climatic adaptation in species with long generation times. We aim to probe if the epigenetic memory involves stable DNA methylation marks retained through the annual cycle and from year to year. For this we use unique well-defined clonal epitypes of Norway spruce with a stable epigenetic memory of the temperature sum experienced during embryogenesis impacting bud phenology. The epigenetic memory is retained year after year in the epitypes and affects the annual growth cycle, timing of bud set, cold acclimation, de-hardening in a predictable and reproducible manner. From these we have characterized DNA methylation patterns in apical buds for 10 time points through the annual cycle of development to observe the differences between epitypes. Due to the massive size of the Norway spruce genome, we used a targeted approach to address the DNA methylation status at a single-base resolution in 3000 selected target genes involved in the timing of phenology, the entire epigenetic machinery, and the circadian clock. We found large differences in methylation patterns for specific genes. Methylation marks look to be patterned throughout the annual cycle. Specific methylation states for some differentially methylated genes may be re-establishing two times a year and persist or cleared in between. The obtained results will be presented and discussed here.