The Samuels lab is happy to announce the publication of our new paper in Current Biology: A polarized supercell produces specialized metabolites in cannabis trichomes. We propose a new model of specialized metabolite trafficking in glandular trichomes based on ultrastructural and immunological investigations of cryofixed cannabis flowers. Using TEM, we demonstrate that the cells responsible for abundant cannabinoid and terpene biosynthesis are interconnected throughout trichome biogenesis, and become polarized during the transition to metabolite biosynthesis and secretion. Using novel polyclonal antibodies we reveal the nanoscale distribution of key enzymes for terpene biosynthesis in plastids (geranyldiphosphate synthase - GPPS), and cannabinoid biosynthesis (tetrahydrocannabinolic acid synthase - THCAS) in the apical cell wall of the glandular disc. These data reveal cannabinoid biosynthesis requires multiple highly distinct microenvironments for the production of valuable cannabinoids, and suggests the cannabinoid precursor cannabigerolic acid (CBGA) is the lipophilic metabolite trafficked from the plastid to the cell wall. Cryofixation revealed an abundance of membrane contact sites among plastids, endoplasmic reticulum, and plasma membrane, facilitating a model of lipophilic metabolite trafficking from plastid to plasma membrane via ER membrane contact sites.
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For Sam's cannabis cell wallpaper in 2021, the Plant & Cell Physiology Journal made his paper the Editor's Choice for the issue and provided him with an Author Highlight. Recently, Sam received the Taylor A. Steeves Award for Best Student Paper in Plant Development, Structure or Morphology from the CBA/ABC, and a runner-up for the CSPB Ragai Ibrahim Best Student Paper.
