Habitat matters - Strong genetic and epigenetic differentiation in Linum catharticum from dry and wet grasslands.

Ellen Pagel,Christoph Reisch,Peter Poschlod

doi:10.1002/ece3.6689

Abstract

Plant species differ in their ecological amplitude, with some species occurring in very different habitats under strongly differentiated environmental conditions. We were interested in to what extent the occurrence of Linum catharticum in dry calcareous grasslands (Bromion) and wet litter meadows (Molinion), two habitats on opposing ends concerning, for example, moisture level, is reflected on the genetic and epigenetic level. Using AFLP (amplified fragment length polymorphisms) and MSAP (methylation sensitive amplification polymorphisms) analyses, we studied the genetic and epigenetic variation of L. catharticum from calcareous grasslands and litter meadows. From each habitat, we included five study sites with 16 individuals per sampling location. We observed lower genetic than epigenetic diversity, but considerable differentiation among habitats, which was stronger on the genetic than the epigenetic level. Additionally, we observed a strong correlation of genetic and epigenetic distance, irrespective of geographic distance. The dataset included a large portion of fragments exclusively found in individuals from one or the other habitat. Some epigenetic fragments even occurred in different methylation states depending on the habitat. We conclude that environmental effects act on both the genetic and epigenetic level, producing the clear differentiation among plant individuals from calcareous grasslands and litter meadows. These results may also point into the direction of ecotype formation in this species.

Highlights

Through the wide variety of global ecosystems, plant species experience an extraordinary range of environmental conditions among and within habitats (Schulz, Eckstein, & Durka, 2014)
Many of these processes depend on genetic variation and evolutionary mechanisms, but there is growing evidence that epigenetic processes play a major role in the response of plant individuals and populations to different or changing environmental conditions, especially on short time scales (Gáspár, Bossdorf, & Durka, 2019; Medrano, Herrera, & Bazaga, 2014)
These results suggest that epigenetic variation is an important mechanism for plants to cope with rapid changes in their environment

Summary

| INTRODUCTION

Through the wide variety of global ecosystems, plant species experience an extraordinary range of environmental conditions among and within habitats (Schulz, Eckstein, & Durka, 2014). Most recent studies focussed on perennial plant species, for example, clonal Populus tremuloides stands (Ahn, Franklin, & Douhovnikoff, 2017), salt marsh perennials (Foust et al, 2016), or a typical grassland species like Plantago lanceolata (Gáspár et al, 2019) All these studies found epigenetic differences, which could at least partially be attributed to differences in their local environmental conditions (e.g., flooding frequency and intensity, habitat openness, and herbivory). The use of dominant markers is a powerful, quick, and easy tool to study nonmodel species without large reference data bases and gives stable results on the genetic and epigenetic structure of populations (Lele, Ning, Cuiping, Xiao, & Weihua, 2018; Schulz et al, 2013) These methods provide a first step toward understanding the role of genetic and epigenetic variation in L. catharticum. We hypothesized that epigenetic variation will show a clear pattern across study sites, while genetic variation within and among sites will be comparably low

| MATERIALS AND METHODS

Findings

| DISCUSSION