小背景：In Arabidopsis thaliana, prolonged cold induces silencing of the potent floral repressor FLOWERING LOCUS C (FLC) by Polycomb group (PcG) chromatin modifiers. This Polycomb-repressed chromatin state is epigenetically maintained and thus ‘memorized’ in subsequent growth and development upon return to warmth.

主观看法：‘Memory of winter cold’ has been viewed as being mitotically stable but meiotically unstable, and thus not to be transmitted intergenerationally.

提出问题：In general, whether and how chromatin-mediated environmental memories are transmitted across generations are unknown in plants.

主要发现：Here, we show that the cold-induced Polycomb-repressed chromatin state at FLC or memory of winter cold is maintained in the egg cell, that is meiotically stable in the process of female gamete formation, and provide evidence that this Polycomb-mediated memory is not maintained in the sperm cell. Moreover, we show that this cold memory is inherited maternally but not paternally to the zygote and early embryos.

结论：Our study demonstrates and further provides mechanistic insights into intergenerational transmission of chromatin state-mediated environmental memories in plants.