Comparative epigenetic and genetic spatial structure in Mediterranean mountain plants: a multispecific comparison

Abstract

Epigenetic information can be heritable, but also respond to key environmental variables in situ, endowing individuals with an additional capacity to adapt to environmental changes. Thus, it is likely that in sesile organisms such as plants, part of the spatial epigenetic variation found across individuals will reflect the environmental heterogeneity of populations. Analysing the departure of the spatial epigenetic structure from the baseline genetic variation can help in understanding the value of epigenetic regulation in species with different breath of optimal environmental conditions. We performed a multispecies study that considered seven pairs of congeneric plant species, each encompassing a narrow endemic with habitat specialization and a widespread species. In three populations per species we used AFLP and methylation-sensitive AFLP markers to characterise the spatial genetic and epigenetic structures. In contrast to widespread species, narrow endemics showed a significant and generalised lower epigenetic than genetic differentiation across species. Within most populations of narrow species, epigenetic variation was less spatially structured than the genetic variation. This pattern resulted from a lack of correlation between epigenetic and genetic information in populations of narrow endemics. We argue that the differences found between narrow endemics and widespread congeners reflect contrasting breaths of environmental requirements. We pose the hypothesis that in species with a narrow niche breath, epigenetic variation may be more similar across populations and among individuals within a population given the expected higher similarity in environmental requirements.

A dynamic epigenetic perspective on above and below-ground phenotypic responses to drought: insights from global DNA methylation inErodium cicutarium

“…Such unexpected result suggested that not only intraspecific variability associated to broad geographical scales and climatic gradients may determine the magnitude of plant phenotypic plasticity mediated by DNA methylation changes (e.g., Bossdorf et al, 2010;Münzbergová et al, 2019;Sammarco et al, 2021). Shortdistance environmental heterogeneity emerged as another fundamental scale leading to intraspecific epigenetic variability (e.g., Herrera et al, 2017;Valverde et al, 2024) whose relevance for plant adaptation to stress deserves further analysis. First, we showed that the magnitude of reduction in DNA methylation of leaves and roots after seed treatment with 5azaC was not homogeneous between provenances (see e.g., Troyee et al, 2022 for heterogenous response between two ecotypes of Thlaspi arvense, and Browne et al, 2020 for heterogenous response in gene transcription between families of Quercus lobata).…”