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 organismsí 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 Epigenetic 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.

 

Along this line, our studies have contributed to illustrate extensive variation in global methylation level across plant species, that is evolutionary related to monoploid genome size (Alonso et al. 2015), and significant variation in methylation patterns of wild plant populations, frequently exceeding genetic variation (Herrera & Bazaga 2010). We have also related such 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) 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.  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.