Spatiotemporal Distribution Patterns of Osthole and Expression Correlation of the MOT1 Homologue in Cultivated Angelica biserrata

Sustainable cultivation of <i>Angelica biserrata</i>, a medicinal species with a bioactive coumarin, Osthole, is hindered by inconsistent metabolite accumulation. To address this limitation, we integrated spatiotemporal metabolomics and transcriptomic analyses. Tissue-specific measurements revealed that root bark accumulates Osthole at 0.30 ± 0.15%, a concentration 11-fold higher compared to root pith and 15-30-fold higher compared to aerial organs. Over time, the Osthole content increased by 195% from September to December, with frost exposure further increasing the accumulation by an additional 170%. Germplasm screening identified an elite accession, AB-222, exhibiting 230% higher Osthole content compared to regional averages. Weighted gene co-expression network analysis identified a gene module strongly correlating with Osthole accumulation. Within this module, <i>AbOMT1</i> (<i>AB04G05077</i>), an <i>O-METHYLTRANSFERASE 1</i> (<i>OMT1</i>) homolog encoding an S-adenosyl methionine-dependent O-methyltransferase, was the top hub gene. <i>AbOMT1</i> expression reflected Osthole dynamics both spatially (three-fold higher in root bark vs. root pith) and temporally. Module functional analysis revealed significant enrichment in phenylpropanoid and monoterpenoid biosynthesis pathways. Our results suggest <i>AbOMT1</i> as a possible key molecular marker for Osthole accumulation, establish frost induction as a strong yield regulator, and suggest AB-222 as an elite germplasm resource.