Plant ecological epigenetics


The DNA sequence does not carry all the information required to determine the phenotype of an organism. Epigenetics studies phenotypic variation that is not accompanied by changes in DNA sequence, but involves a variety of reversible chemical modifications that occur on the DNA and on its interacting proteins, and impinge on chromatin structure. Such epigenetic mechanisms contribute to complex traits and proper organism's development.
In plants, DNA cytosine methylation is an important and complexly regulated epigenetic mechanism involved in the response to several environmental factors. Our understanding of its role in ecological adaptation and evolutionary change is still vague and Ecological Epigenetics studies should merge ecological experimental design with appropriate molecular analyses to elucidate the contribution of epigenetics to both phenotypic variation of wild plants and their functional responses to rapid environmental changes (see Richards et al. 2017 for a review).
Along this line, our studies have contributed to illustrate extensive variation in global methylation level across plant species,  and significant variation in methylation patterns of wild plant populations, frequently exceeding genetic variation (Herrera & Bazaga 2010, Medrano et al. 2020). Across species, global methylation spanned a 10-fold range (4 and 40 %, aprox.) and is evolutionary related to monoploid genome size (Alonso et al. 2016). Further, our studies suggested that the genomes of tropical species are on average less methylated than those of Mediterranean ones, and woody plants have genomes with lower methylation than perennial herbs (link to Alonso et al. 2019). At intraspecific level, we have related the extensive natural epigenetic variation to impact of biotic stress imposed by herbivores (Herrera & Bazaga 2011, Herrera & Bazaga 2013) and abiotic factors such as drought (Medrano et al. 2014; see also Alonso et al. 2016 for a literature review).

Heritability across generations of such epigenetic marks (Herrera et al 2013, Herrera et al. 2018) and the strength of the relationship between genetic and epigenetic variation of wild populations (Herrera et al. 2016) are two key issues that should be analysed more deeply in order to better calibrating the impact of epigenetics in adaptation of wild plant populations (Herrera et al. 2017). Most recently, we have also documented the relevance of within-plant epigenetic mosaicism and its relationship with reproductive output (Alonso et al 2018, Herrera et al. 2019), and plant-animal interactions (Herrera et al. 2019).

We take part of EPIDIVERSE (, a Marie Skłodowska-Curie Innovative Training Network joining academic groups from plant ecology, molecular (epi)genetics and bioinformatics with life science companies to explore epigenetic mechanisms and their adaptive relevance in natural plant populations of species with different life-histories. We focused on epigenetic changes associated to herbivory.

Our current projects seek to understand the links between genetic, epigenetic and phenotypic variation in plants growing in harsh and unpredictable environments like Mediterranean mountains (Balao et al. 2018 , Medrano et al. 2020) and their relevance for plant-animal interactions.