559 / 2019-03-15 23:17:08

Distinct epigenome changes upon tissue regeneration

Somaclonal Variation, Epimutation, Mutation

Epigenetic Regulation > Epigenetic Regulation

Clonally propagated plants are expected to be invariant. Nevertheless, they often display heritable phenotypic variation, a phenomenon known as somaclonal variation. Several studies have shown that genetic and epigenetic modifications induced during the regeneration process are associated with this phenomenon. Depending on the species, plants can be clonally propagated from different tissues by different regeneration protocols. However, it is unknown whether regeneration protocol and/or tissue of origin contribute to mutation and epimutation rate in regenerated plants.
We have investigated the fate of genomes and epigenomes in three different Arabidopsis thaliana accessions following clonal propagation. For that, we generated clonal individuals from different tissues through different protocols, hormone-based tissue culture and somatic embryogenesis induced by ectopic expression of embryonic transcription factors. We found elevated DNA mutation rates in all samples, yet without systematic differences between tissue of origin and regeneration protocol. In contrast, the epigenetic landscape was affected more by the regeneration protocol than by tissue type used for regeneration, and these observations were consistent in all three accessions tested.
Our findings constitute a comprehensive atlas of mutations and epimutations associated with somaclonal variation, and provide new and exciting possibilities for limiting phenotypic variation in clonal lines.