Data from: Improved demethylation in ecological epigenetic experiments: testing a simple and harmless foliar demethylation application

1. Experimental demethylation of plant DNA enables testing for epigenetic
effects in a simple and straightforward way without the use of expensive
and laborious DNA sequencing. Plants are commonly demethylated during
their germination with the application of agents such as 5-azacytidine
(5-azaC). However, this approach can cause unwanted effects such as
underdeveloped root systems and high mortality of treated plants,
hindering a full comparison with untreated plants, and can be applied only
on plant reproducing by seeds. Here we test a simple alternative method of
plant demethylation, designed to overcome the shortcomings of the
germinating method. 2. We compared a novel method of demethylating plants,
based on periodical spraying of 5-azaC aqueous solution on established
seedlings, with the previous method in which seeds were germinated
directly in 5-azaC solution. We quantified the amount of methylated DNA
and measured various aspects of plant performance. Also, we demonstrated
its applicability in ecological epigenetic experiments, by testing
transgenerational effects of plant-plant competition. 3. We found that the
spray application had similar DNA-demethylating efficiency than the
germination method, particularly in the earlier phases of plant
development, but without unwanted effects. The spray application method
did not reduce plant growth and performance compared to untreated plants,
as opposed to the traditional method which showed reduced growth. Also,
the spray application method equalized the epigenetically-modified plant
features of seedlings coming from plants grown under competition and
plants growing without competition, demonstrating its application in
ecological epigenetic experiments. 4. We conclude that regular spraying of
5-azaC solution onto established seedlings surpassed the
germination-in-solution method in terms of vigor and fitness of treated
plants. This novel method could thus be better suited for experimental
studies seeking valuable insights into ecological epigenetics.
Furthermore, the spray method can be suitable for clonal species
reproducing asexually, and, most importantly, it opens the possibility of
community-level experimental demethylation of plants.