Abstract Detail

Plant epigenetics: phenotypic and functional diversity beyond the DNA sequence

Toivainen, Tuomas [1], Fossdal, Carl Gunnar [2], Hytönen, Timo [3], Gaut, Brandon [4].

A role of epigenetic variation in perennial climate adaptation.

A role of epigenetic variation in perennial climate adaptationBecause of the rapid climate change, it is crucial to understand all heritable variation contributing to adaptation. In addition to genetic variation, DNA methylation can be inherited across generations, but its role in adaptation is largely unknown. We use woodland strawberry as a model to explore genetic and epigenetic mechanisms of adaptation. It is a common, mixed-mating, clonally-propagating, perennial plant with a small genome of ~220Mb growing in diverse climates across Eurasia and North-America. Our common garden experiments on European accessions collected across latitudinal gradient revealed a strong correlation between flowering time and latitude of origin showing that the species has adapted to its local habitats across the latitudinal cline. Population genomic analyses also revealed that European woodland strawberry clusters into the Eastern and Western genetic groups that are growing in the continental and oceanic climates, respectively, indicating also the presence of an east-west axis in adaptation.To study a role of DNA methylation in perennial climate adaptation we carried out whole genome bisulphite sequencing of 44 samples from Spain, Italy, Finland and Iceland as well as from highly differentiated northern Norwegian Tromso, Kåfjord and Alta populations. These populations were selected because of their particularly interesting and diverse population histories. Alta, Kåfjord and Finland populations that belong to the eastern cluster started to colonize Northern Europe from southern Europe during Holocene climatic optimum, less than 9 thousand years ago, while plants in Tromso and Icelandic populations were diverged from Spanish and Italian populations five thousand year ago. They dispersed to Tromso during Minoan and Roman warm periods, when Kåfjord and Tromso populations also started to hybridize and finally Icelandic population diverged from these hybrids less than 1000 years ago.Our population epigenomic analyses revealed that there is a clear positive correlation between latitude of origin and DNA methylation on CG sites, northern Iceland and Tromso populations showing a higher proportion of CG methylated sites compared to southern European populations. In addition, we found that the genome-wide CHG-methylation levels differed significantly between populations, western samples being more highly CHG-methylated compared to the Eastern samples. Interestingly, GO enrichment analysis on the most highly differentiated genes between the eastern and western genetic clusters revealed several GO-categories involved in epigenetic processes, and Chromomethylase 3 was found as one of the top candidate genes for the observed differential genome-wide CHG methylation pattern. The latest results will be discussed

Related Links:
Bridget Curran on the web
Jolles Lab

1 - University of Irvine, 321 Steinhaus Hall, Irvine, California, 92697, United States
2 - NIBIO, Norway
3 - University of Helsinki, Agricultural sciences, Finland
4 - University of Irvine, Ecology and evolutionary biology, 321 Steinhaus Hall, Irvine, California, 92697, United States

Local Adaptation.

Presentation Type: Symposium Presentation
Session: SY1, Plant epigenetics: phenotypic and functional diversity beyond the DNA sequence
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 11:15 AM
Number: SY1004
Abstract ID:702
Candidate for Awards:None

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