PubMed · 2026-05-22
Scientists identified a molecular complex (ATX1-COMPASS-like) that controls when tree peonies wake from winter dormancy by chemically tagging DNA to switch on growth genes — a discovery that explains why adequate cold exposure and certain plant hormones are required before buds will break in spring.
A specific histone mark called H3K4me3 — but not the related H3K4me1 or H3K4me2 — was the key epigenetic signal activated by both prolonged cold and gibberellin (GA3) treatment during dormancy release.
Four proteins (PsWDR5a, PsRBL, PsASH2R, PsATX1) were upregulated by chilling and GA3, and overexpressing them significantly promoted bud burst by raising genome-wide H3K4me3 levels.
The proteins assemble into a single functional complex where PsRBL acts as a molecular bridge and PsATX1 is the enzyme that writes the H3K4me3 mark, activating downstream growth genes including cell-cycle regulators (PsCYCD3.1, PsCYCD3.3) and a cell-wall loosening enzyme (PsBG6).
