## 2 Results
### Proteome Responses of Glandular Trichome Disc Cells to Phytohormone Treatments  
Principal component analysis (Figure 2A) revealed that the GT disc cell proteome responded differently to a range of phytohormone treatments. Treatment with ethephon (ETH), abscisic acid (ABA), or brassinolide (BR) overlapped with the ellipse from the 24 h control proteome (CTR_24h), while the response of those treated with gibberellic acid (GA), diethyldithiocarbamate (DIECA), kinetin (KIN), jasmonic acid (JA), and salicylic acid (SA) segregated away from CTR_24h. Of note, KIN, JA, and SA separated furthest away from CTR_24h. DIECA is an inhibitor of jasmonic acid synthesis, thereby inhibiting its signalling pathway [46; 47]. A total of 448 proteins (32% of quantified proteome) were differentially abundant due to at least one phytohormone treatment when compared to the CTR_24h (Figure 2B). Hierarchical clustering revealed that DAPs grouped into two clusters, those that generally  
Figure 2: Cannabis (_Camabis sativa_ L.) glandular trichome disc cells were incubated _in vitro_ on plates (\(n=4\)) for 24 h with different phytohormone treatments, and their proteome was quantified (1400 proteins). Treatments were separated by principal component analysis (**A**) and hierarchical clustering ([PERSON]’s method) by log\({}_{2}\)(fold-change) of the differentially abundant proteins (DAPs) (**B**). Non-significance assigned a log\({}_{2}\)(FC) of 0. The percent change of the total quantified proteome was tabulated for each phytohormone treatment (**C**). DAP was significant if \(p<0.05\) and fold-change either \(<\)0.67 or \(>\)1.5. Abbreviations: CTR_0h, 0 h control; CTR_24h, 24 h control; ABA, abscisic acid; BR, brassinolide; DIECA, diethyldithiocarbamate; ETH, ethephon; GA, gibberellic acid; KIN, kinetin; JA, jasmonic acid; SA, salicylic acid. increased in response to a phytohormone and those that generally decreased (Figure 2B). Phytohormones grouped into two clusters as well with group 1 comprising GA, BR, DIECA, ETH, and ABA and group 2 comprising KIN, SA, and JA. DAPs in the increasing cluster were generally enriched for processes involved in carbohydrate metabolism, phenyl-propanoid biosynthesis, and jasmonic acid biosynthesis, while DAPs in the decreasing cluster were enriched for catabolism, fatty acid, amino acid, and isoprenoid metabolism (Supplementary Figure S1). Group 2 phytohormones caused the greatest change in the GT disc cell proteome (Figure 2C), with KIN, SA, and JA causing 3.4%, 4.0%, and 3.7% of the quantified proteins to increase in abundance, respectively, and 7.3%, 9.0%, and 8.1% of the proteins to decrease in abundance, respectively. Group 1 phytohormones caused a lower amount of change in the proteome with GA, BR, DIECA, ETH, and ABA causing at most 2.9% of the quantified proteins to increase in abundance and at most 2.6% to decrease. Gene ontology (GO) enrichment analysis was conducted on each of the individual phytohormone DAP groups (Figure 3). For group 1 phytohormones, increasing DAPs of BR, ETH, and ABA did not cause enrichment significantly for any biological processes. DIECA caused an increased enrichment for terms involved in phenylpropanoid biosynthetic process, and the tetrahydrofolate metabolic process and GA did so for terms related to glycolysis and nucleoside catabolism (Figure 3A). In contrast, increasing DAPs in all three group 2 phytohormones caused enrichment for specific biological processes. Both SA and JA were enriched for photosynthesis and generation of precursor metabolites and energy. SA was additionally enriched for the phenylpropanoid biosynthetic process and alpha-amino acid metabolic process. KIN was only enriched for lipid oxidation and water stress (Figure 3A). Decreasing DAPs due to the phytohormone treatments caused enrichment for a range of biological processes in GT disc cells (Figure 3B). DAPs of group 1 phytohormones were enriched for different processes with some overlap, with the exception of ABA, which was not enriched for any biological processes.