Small differences in DNA sequence contribute to heritable variations within a species, as do chemical modifications of DNA called epigenetic changes. In order to better understand the importance of such epigenetic changes for plant evolution, an international research team led by Professor Oliver Bossdorf from the Institute of Evolution and Ecology at the University of Tübingen studied a large number of populations of Thlaspi arvense or field snail in a Europe-wide study. The researchers linked DNA sequences and environmental data from the places of origin with the epigenetic modifications of this wild plant. According to their findings, much of epigenetic variation is primarily determined by DNA sequence. However, part of the epigenetic variation is strongly linked to the climatic conditions of the place of origin of the plant. In agriculture, field apricot could become important in the future as a winter cover crop and as a source of biofuel. The study was published in the latest edition of PLoS genetics.
Thlaspi arvense is an annual white-flowered wild plant in the cruciferous family, native to much of Europe and Asia. Its common name comes from the round shape of its pods, reminiscent of coins. For the study, the research team collected seeds from 207 wild pennycress populations across Europe and grew the seeds in the lab under standard conditions. From samples of these plants, they then analyzed the complete DNA sequences, as well as “methlyomes”, the complete sequence of DNA methylations – important epigenetic changes that influence whether and how often certain genes are transcribed.
“The importance of epigenetics for plant evolution and adaptability can only be understood if extensive, high-resolution data on genetic and epigenetic variation across many plant origins and their environmental conditions are available. Until now, these data were only available for a few model plants in plant research, such as Arabis, Arabidopsis thaliana“, explains Olivier Bossdorf. He and his team have now, for the first time, performed such a combined study on a wild plant collected from many natural sites.
“We found strong geographic variation in the DNA methylations of the field pennycress genome. Much of this is directly related to DNA sequence. However, depending on the genomic background, a significant proportion is also determined by the environmental conditions at the plant’s place of origin,” says Bossdorf. This suggests that the field snail’s epigenetic variations may play a role in its short-term adaptation to climatic conditions. Field pennycress is currently being developed as the basis for a new biofuel and will likely be used as a winter cover crop in the future, says Bossdorf. “Our results could therefore also be useful for agriculture, in particular for the cultivation of field pennycress under changing climatic conditions.”
Dario Galanti, Daniela Ramos-Cruz, Adam Nunn, Isaac Rodríguez-Arévalo, JF Scheepens, Claude Becker, Oliver Bossdorf: Genetic and environmental factors of large-scale epigenetic variation in Thlaspi arvense. PLoS genetics, https://doi.org/10.1371/journal.pgen.1010452