Linking DNA methylation with performance in a woody plant species

Epigenetic factors are increasingly being viewed as important mechanisms in organism performance. However, advances in plant epigenetics rely mostly on studies of short-lived model or cultivated species and there is a current gap in knowledge on wild plants, especially on woody plant species, that still needs to be addressed via empirical studies. Through a greenhouse experiment we compared the genetic (microsatellites) and epigenetic (methylation-sensitive amplified polymorphisms) variation in mother plants and their open-pollinated offspring of the Mediterranean woody plant Pistacia lentiscus. We also assessed whether the inherited DNA methylation patterns were related to the early offspring performance. Our results revealed (i) higher levels of relative DNA methylation in mother plants than in their offspring, although the amount of methylation in the offspring was remarkable; (ii) a significant relationship between relative methylation levels between the two life stages; (iii) a high epigenetic structure among families that was decoupled to the genetic structure; and (iv) a significant relationship between the relative DNA methylation levels and seedling phenotypic trait variation with higher levels of methylation in the genome being associated to a poorer performance. Our results stress the impact that epigenetic inheritance might have in evolution through its influence in seedling development, and that epigenetic effects can be detected even at early stages of the life cycle of woody long-lived species.