Chromatin accessibility profiling and transcriptomics of Marchantia polymorpha heat‑shock transcription factor (HSF) mutants reveal that HSFA1 governs the placement of cis‑regulatory elements for heat‑induced gene activation, a mechanism conserved across plants, mice, and humans. Integrated gene regulatory network modeling identifies MpWRKY10 and MpABI5B as indirect regulators linking phenylpropanoid and stress pathways, while abscisic acid influences gene expression downstream of HSFA1 without broadly reshaping chromatin. A cross‑species, cross‑condition machine‑learning framework successfully predicts chromatin accessibility and expression, underscoring a conserved regulatory logic in stress responses.

The study mapped the subcellular localization of isoprenoid biosynthetic enzymes in Marchantia polymorpha, confirming most predictions and identifying oil body cells as primary sites of terpene synthesis. Overexpression and CRISPR knockout of the ABC transporter ABCG1 revealed its essential role in retaining sesquiterpenes within oil bodies, while attempts to boost heterologous diterpene and triterpene production in oil bodies did not increase yields.