Genome-wide methylome stability and parental effects in the worldwide distributed Lombardy poplar: Poster - Flash presentation

Tree species rely on their ability to adapt to environmental change, with epigenetic mechanisms playing a key role by regulating gene expression. Understanding how epigenetic variation arises and persists across generations is essential to assess its evolutionary impact. The Lombardy poplar—a clonal variant of Populus nigra L. derived from a single 18th-century tree—is ideal for studying long-term epigenetic effects, as it has been widely propagated by cuttings across diverse climates. This study combines two observational methylome analyses and a phenotypic experiment to examine environmental and generational effects. In the first methylome study, we assessed seasonal and generational methylation changes. Methylomes in CG-contexts remained stable across locations and generations, while CHH-contexts showed seasonal variability. The second study tested whether methylation patterns in non-native environments reflected the parental climate but found no significant correlation. The third experiment evaluated phenotypic plasticity, focusing on bud set timing. A weak but statistically significant parental environment effect was detected, though it was overshadowed by the influence of the current environment. In conclusion, CG-context methylation appears stable and lineage-specific, making it a useful biomarker for tracing common ancestry and environmental history in Lombardy poplar.