Abstract
Background/Objectives:Paeonia delavayi, a high-altitude-adapted medicinal and oil-producing plant, exhibits broad elevational distribution. Understanding how environmental factors regulate its growth across altitudes is critical for optimizing cultivation and exploiting its economic potential. Methods: In this study, we conducted a comprehensive Iso-Seq and RNA-seq analysis to elucidate the transcriptional profile across diverse altitudes and three seed developmental stages. Results: Using Pacbio full-length cDNA sequencing, we identified 39,267 full-length transcripts, with 80.03% (31,426) achieving successful annotation. RNA-seq analysis uncovered 11,423 and 9565 differentially expressed genes (DEGs) in response to different altitude and developmental stages, respectively. KEGG analysis indicated that pathways linked to fatty acid metabolism were notably enriched during developmental stages. In contrast, pathways associated with amino acid and protein metabolism were significantly enriched under different altitudes. Furthermore, we identified 34 DEGs related to fatty acid biosynthesis, including genes encoding pivotal enzymes like biotin carboxylase, carboxyl transferase subunit alpha, malonyl-CoA-acyl carrier protein transacylase, 3-oxoacyl-ACP reductase, 3-hydroxyacyl-ACP dehydratase, and stearoyl-ACP desaturase enoyl-ACP reductase. Additionally, ten DEGs were pinpointed as potentially involved in high-altitude stress response. Conclusions: These findings provide insights into the molecular mechanisms of fatty acid biosynthesis and adaptation to high-altitude stress in peony seeds, providing a theoretical foundation for future breeding programs aimed at enhancing seed quality.