Single-cell RNA sequencing reveals a key regulator PfLTP2 affecting glandular trichomes development and perillaldehyde accumulation in Perilla

Glandular trichomes (GTs) are important organs of synthesis and storage for terpenoid, but the regulatory mechanism of GTs development still has some unknown aspects. Perilla is important medicinal and aromatic plant, and there are four types GTs existed in Perilla . The peltate GTs density is clearly positive correlation with perillaldehyde (PAE) content in different Perilla cultivars. To elucidate the molecular basis of PAE synthesis and GTs development, we constructed the single-cell transcriptome sequence of perilla leaves in three PA-type Perilla cultivars, specially annotating cell populations as epidermal cells (ECs) and glandular trichome cells (GTCs). Pseudotime trajectory analysis revealed that the developmental trajectory of GTCs overlapped with that of upper epidermal cells (UECs), suggesting that both lineages may be driven by shared regulatory genes controlling differentiation. Furthermore, the co-expression network analysis identified lipid transfer protein PfLTP2 as core regulators to promoting GTs development and PAE accumulation. PfLTP2 is specific located in the secretory cells of GTs and significantly increased the density of GTs in transgenic tobacco. The transient overexpression and VIGS silencing of PfLTP2 result in related change of peltate glandular trichomes (PGTs) density and PAE accumulation. Interestingly, the PfGL3 and PfWEKY7 regulate PfLTP2 to influence the GTs development and PAE synthesis. Moreover, overexpression of PfLTP2 affects the gene expression in the pathways of fatty acid, glycerolipid and glycerophospholipid metabolism. The interesting result suggest that PfLTP2 , as a key gene, promotes the GTs development and PAE synthesis, accompanied by changes in lipid transport. The findings enrich the molecular understanding of GTs development and PAE accumulation in Perilla , providing a basis for improving the quality of traditional Chinese medicines.