Trans-generational adaptation to maternal climate through hormone transport in plants

Whether and how organisms can inherit environmental information from their parents is a major question in evolutionary theory. Plants have evolved to link reproductive development to seasonal environmental cues and seed dormancy is highly contingent on the environmental temperature during seed set, although the mechanism by which seeds acquire seasonal timing information is unclear. Here we show that loss of maternal like heterochromatin protein 1 (LHP1) causes an inability of progeny seeds to sense temperature and that this is linked mechanistically to reduced ABA levels in seeds and hyperaccumulation of free nitrate. Remarkably, single cell transcriptomics reveals that in both maternal fruit and seed tissues, the effect of small changes in temperature closely phenocopies the lhp1 mutant phenotype and ABA biosensor imaging reveal large fluxes of maternal ABA into seeds is modulated by temperature cues. We show that temperature activates ABA production in leaves and that maternal ABA is necessary and sufficient for progeny seeds to acquire seed dormancy. Thus, we reveal that the climate experience of mother plants causes adaptation of progeny behaviour via hormone transport during seed set. Overall design: Col-0 plants were grown at 22°C till bolting, then half plants were transferred to 16°C. At bent stage, siliques from 2 different temperature were dissected to separate fruit tissue and seed tissue which were sequenced seperately.