Strigolactone signaling repressor SMXL7 modulates genome architecture via JMJ30-mediated H3K27me3 demethylation in Arabidopsis.

Recent advances indicate that epigenetic regulators critically govern hormone signaling networks, such as abscisic acid, ethylene, jasmonate, gibberellin, and cytokinin pathways in plants. Nevertheless, whether strigolactone (SL) modulates chromatin dynamics and genome architecture through epigenetic mechanisms remains largely unexplored. Here, we demonstrate that SUPPRESSOR OF MAX2-LIKE7 (SMXL7), a repressor of SL signaling, restructures chromocenter organization through H3 trimethylation at K27 (H3K27me3)-mediated epigenetic regulation. Moreover, SMXL7 associates with histone H3K27me3-related heterochromatin and controls genome-wide H3K27me3 levels through incorporating the histone demethylases JUMNOJI 30 (JMJ30) into the SMXL7 condensates, modulating chromatin accessibility and genome architecture. Our findings provide evidence that SMXL7 influences higher order chromatin organization in planta and suggest a novel mode of SL signal transduction.