"Methylome, transcriptome and phenotype changes induced by temperature during sexual reproduction in Fragaria vesca"
Yupeng Zhang(张宇鹏)1,2, Tuomas Toivainen3, Kathryn Mackenzie3, Igor Yakovlev1, Paal Krokene1, Timo Hytonen3, Paul E. Grini2* and Carl Gunnar Fossdal1*
Table S1 - S10
The survival and competitive success of perennial plants in temperate climates depend on a balance between cold tolerance, effective use of the relatively short growing season, and flowering at the appropriate time. No previous studies have explored if the temperature conditions experienced during sexual reproduction have any lasting epigenetic effects in Fragaria vesca. We examined this for five European ecotypes from Spain (ES12), Iceland (ICE2), Italy (IT4), and Norway (NOR2 and NOR29). We found statistically significant changes for three of four phenotypic features investigated under common garden conditions, indicating the existence of a temperature-induced memory effect during embryogenesis and seed development in F. vesca. However, significant changes were found only in two ecotypes: NOR2 showed altered flowering time, growth point, and petiole length and ES12 had more growth points. In the three remaining ecotypes there were no significant phenological effects of the temperature conditions experienced during sexual propagation. This indicates that genetic differences between ecotypes in the epigenetic machinery, or factors impacting this, affect an epigenetic memory-type plasticity to the temperature conditions experienced during sexual propapagation. We also observed significant differences between ecotypes in DNA methylation marks in repetitive elements, pseudogenes and genic elements. The transcriptomes were also altered differentially in an ecotype-specific manner by the temperature conditions experienced during embryogenesis. However, there was much variation between progenies within each treatment and no clear connection could be observed between DNA methylation changes and the transcriptome reprogramming. This within-treatment variability could indicate that sexual reproduction (meiosis) not only results in allelic redistribution causing genetic variation but also in epigenetic reprogramming that increased the epigenetic variation in progeny in Fragaria. vesca.
