Heads Up: Transcriptomics Reveal Functional Roles of Cannabis Glandular Trichome Stalks

Cannabis sativa glandular trichomes (CsGT) are the primary sites of cannabinoid biosynthesis. They consist of a metabolically active head and a structurally supportive stalk. While the biosynthetic role of the head is well established, understanding of the functional contribution of the stalk has lagged. Here, we performed an integrated proteomic and transcriptomic analysis of isolated CsGT head and stalk tissues to identify their distinct roles. While proteomic analysis found 35 proteins higher in the stalk compared to the head, the transcriptomic analyses suggest the true functionality of the stalk, with 6018 genes showing higher expression in this tissue. Marker gene analysis showed a predominantly epidermal signature for head cells, while stalk cells also showed signatures for vascular cell types. Congruently, the transcriptomic results showed genes with higher expression in the head associated with specialized secondary metabolite production and accumulation, while the stalk displayed enrichment for genes related to active growth, vascular, apoplastic and symplastic transport, as well as sugar and hormone signalling. These findings support a model in which the stalk is a complex epidermal tissue, highly distinct from the head, that facilitates metabolite transport, signalling, and precursor supply to the glandular head. This study provides the first multi-omics characterization of CsGT stalk function, identifying it as a key contributor to trichome productivity and a potential target for optimizing cannabinoid yield.