The study investigates the role of the chromatin regulator MpSWI3, a core subunit of the SWI/SNF complex, in the liverwort Marchantia polymorpha. A promoter mutation disrupts male gametangiophore development and spermiogenesis, causing enhanced vegetative propagation, and transcriptomic analysis reveals that MpSWI3 regulates genes controlling reproductive initiation, sperm function, and asexual reproduction, highlighting its ancient epigenetic role in balancing vegetative and reproductive phases.

The study characterizes the single-copy S-nitrosoglutathione reductase 1 (MpGSNOR1) in the liverwort Marchantia polymorpha, showing that loss-of-function mutants generated via CRISPR/Cas9 exhibit marked morphological defects and compromised SNO homeostasis and immune responses. These findings indicate that GSNOR-mediated regulation of S‑nitrosylation is an ancient mechanism linking development and immunity in early land plants.

Phylogenetic analysis reveals that non‑seed plants, exemplified by the liverwort Marchantia polymorpha, possess a streamlined repertoire of cyclin and CDK genes, with only three cyclins active in a phase‑specific manner during vegetative development. Single‑cell RNA‑seq and fluorescent reporter assays, combined with functional overexpression studies, demonstrate the distinct, non‑redundant roles of MpCYCD;1, MpCYCA, and MpCYCB;1 in G1 entry, S‑phase progression, and G2/M transition, respectively.

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.