Epigenetic and transcriptomic memory in strawberry. Heritability of stress-induced DNA methylation patterns in the diploid woodland strawberry (Fragaria vesca sp.)

We have previously reported that different stresses can lead to substantial DNA methylation changes in strawberry. Here, we wanted to assess the heritability of heat-stress induced DNA methylation and transcriptional changes following asexual and sexual reproduction in a plant. Woodland strawberry (Fragaria vesca) is an ideal model to study epigenetic inheritance in plants because it presents two modes of reproduction: sexual and asexual. Here we wanted to assess if heat-stress induced DNA methylation changes can be transmitted via asexual reproduction and whether past stresses can also affect sexually propagated progenies. Our genome-wide study provides evidence for a memory acquisition and maintenance in F. vesca. We found that certain DNA methylation changes can stably be transmitted over at least three asexual generations. Finally, the first sexual generation by selfing from stressed maternal and their respective non-stressed asexual daughter plants showed both shared and unique stress responses. This suggests that an acquired molecular memory from the previous heat-stress event was transmitted. This molecular memory might be involved in functional plasticity and stress adaption, an important aspects that will have to be investigated in future studies. Finally, these findings may contribute to novel approaches that may contribute to the breeding of climate-ready plants.