Multi-omics analysis elucidates sesquiterpenoid compounds and identifies IrTPS3 as a key multifunctional terpene synthase in roots and rhizomes of <i>Inula racemosa</i>

These findings support that IrTPS3 is likely the principal enzyme involved in sesquiterpenoid biosynthesis in I. racemosa, providing a foundation for further studies aimed at metabolic engineering and sustainable production of these valuable compounds.