Comparative analysis of gene expression and metabolites in female and male Cannabis sativa flowers
Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China
Daqing Branch of Heilongjiang Academy of Agriculture Science, Daqing 163319, China
∗Corresponding author qingtang1996@163.com∗∗Corresponding author luanmingbao@caas.cn∗∗∗Corresponding author xuying0420@163.comSummary
Cannabis sativa L., a dioecious plant, exhibits sex-specific medicinal active ingredients. However, their causes remain unexplored. In this study, C. sativa flowers exhibited significant intersexual morphological differences, particularly in glandular trichomes. 1676 DEGs and 700 DAMs were identified. Among 149 genes related to sexual differentiation, 77 encode hormone-related products presumably involved in dioecy. Female flowers had cannabinoid levels 16.88 times those of males. Metabolomic sequencing identified 28 distinct terpenoids. We identified CsDXPS1, CsLOX2, CsLOX1.5, CsAAE18, CsAAE6-1, CsAAE6-2, CsGGR, and the metabolite mevalonate-5P; all except AAE6 were highly expressed in female flowers, regulating terpene and cannabinoid production. Seven glandular-trichome-related DEGs showed significant positive correlation with cannabinoid and terpene abundance; female-enriched CsMYC4 (TPS activator) and CsMYB49 (secretion enhancer) emerged as pivotal transcriptional regulators. These results provide a theoretical basis for the directional selection of female and male strains with high production and cultivation value.
Graphical abstract
Highlights
- •1,676 DEGs and 700 DAMs are revealed in Cannabis sativa female and male flowers
- •Female flowers show 16.88× cannabinoids and 28 distinct terpenoids versus males
- •Mevalonate-5P and 8 DEGs increase cannabinoid/terpene biosynthesis in female flowers
- •Seven trichome-DEGs and 112 TFs correlate with cannabinoid and terpene content
Teaser
Natural sciences; Plant biochemistry; Plant bioinformatics; Plant Biology; Plant physiology; Plant development
Article notes
Published: February 7, 2026
Introduction
Dioecious plants evolved from hermaphroditic ancestors to avoid inbreeding depression and promote cross-pollination.1 Sexual specialization manifests as differences in morphology, function, biomass, and metabolic products between female and male plants.2 As such, a plant’s importance to consumers and economic value also tends to vary across sexes. For instance, female and male plants of the dioecious gymnosperm Ginkgo biloba L. have distinct uses3 that are reflected in morphological differences. The female plant's fruit contains various medicinal ingredients and nutritional value, whereas the medicinal value of the male plant is relatively low. Female plants are shorter than male plants at the same age, but have sturdier stems and more lateral branches. Female plants also have smaller leaves and shed leaves earlier than male plants.4 Male ginkgo has higher flavonoid content in roots, stems, and leaves than female ginkgo,5 whereas female plants have higher shikimic acid content in fallen leaves than male plants.6 In poplars, males have more metabolites of phenylpropane, polyketones, organic oxygen compounds, and lipids than females.7 Male kiwifruit strains are significantly higher in flavonoids, anthocyanins, total phenols, and free ubiquitin than female strains.8 However, female strains have higher free polyamine content than male strains.9,10,11 In papaya, testosterone is upregulated in male roots, whereas norgestrol is upregulated in female roots.12 In Juniperus communis, female shoots have significantly more germacrene than male shoots.13
Sexual differentiation in dioecious plants is genetically determined,14 with floral organ development regulated by MADS-box genes. In ginkgo flowers, GbMADS16 varies across male flower development, but not across female flower development.15 In poplars, the MADS-box genes APETALA3 (AP3) and PISTILLATA (PI) are key in stamen formation, and downregulation results in the production of female flowers.16 In Salix viminalis, SvSAUR is significantly associated with female gametophyte development and flower formation.17 In Morella rubra, chromosome 8 contains a female-specific region with genes unique to female plants (MrASP2, MrCPS2, MrSAUR2, and MrFT2).18 In red bayberry (Myrica rubra), the ethylene signaling pathway involves MR1G019545.1 (ETR1), a gene associated with sex determination.19 In poplar and willow, GAMYB is male-flower-specific and important to pollen development.20 Female buds of Actinidia chinensis var. chinensis expressed Cdc5L at 2.22 times the level in male buds; this protein promotes fibroblast growth and could potentially be involved in the process of pollen formation.8 In female Salix viminalis, SvTOGT1 and SvHST are significantly upregulated, affecting ovule development and the phenylpropyl and flavonoid metabolic pathways.17
Cannabis sativa is an annual, herbaceous, erect, and typically dioecious plant.21 Cannabis sativa has considerable economic value as an oil, fiber, and medicinal source. Female and male plants exhibit distinct morphology that influences their applications. The male plant of C. sativa has superior fiber quality to female plants, whereas female plants have more cannabinoids and other beneficial metabolites.22 The main organs responsible for the synthesis and storage of cannabinoids and terpenes are the secretory glandular trichomes in C. sativa; unsurprisingly, these structures have a higher distribution on the bracts of female flowers than of male flowers.23,24 The cannabinoid content varies in different organs, with the content in inflorescences being higher than that in leaves.25 Furthermore, the cannabinoid content in cannabis is influenced by genetic factors,25 and by environmental and cultivation conditions,26 such as stress conditions,27 mineral nutrition,28,29 and planting density.30 The sex ratio of C. sativa is influenced by hormones such as GA3, 6-BA, and IAA.31,32 Transcriptome sequencing identified approximately 200 genes that participate in male organ development (anthers and pollen) through hormone signal transduction.33
Although some studies have investigated intersexual differences in secretory metabolites and gene expression of C. sativa, combined transcriptomic and metabolomic analyses of these differences have not been performed. Therefore, this study conducted a joint analysis of female and male C. sativa flowers to quantify intersexual differences in metabolites and gene expression. This study provides a foundation for the cultivation, selection, and function-directed breeding of C. sativa female and male plants.
Results
Morphological difference between female and male flowers
Female and male C. sativa flowers differed visually (Figure 1).34 Female flowers (Figure 1A) were spike-like, green, with dense inflorescences and without obvious floral organs (Figure 1A1-2). The pistil comprised a thin, transparent sepal envelope, without a petalous stalk. The ovary was composed of a bilocular carpel. The stigma was filamentous and bilobated. Both stigma and sepal surfaces were covered with glandular hairs (Figure 1A3).
Male flowers were compound racemes with loose inflorescences (Figure 1B), distinct floral organs (Figure 1B1-2), stalks, five yellowish-green sepals, and five stamens (Figure 1B3). Under an inverted microscope, female flowers had higher secretory glandular hair density than male flowers. Any glandular hairs on male flowers were non-secretory.
Differential gene expression of female and male flowers
Transcriptome sequencing with high throughput resulted in the identification of 19,203 genes, from which we screened out 1676 differentially expressed genes (DEGs) (fold-change >2, Q-value ≤0.05). Of these DEGs, 759 were highly expressed in male flowers, and 917 were highly expressed in female flowers (Figure 2A; Table S1), whereas 112 genes were not expressed in male flowers and 118 were not expressed in female flowers. The 30 most significant DEGs included four genes not expressed in female flowers and nine genes not expressed in male flowers (Figure 2B).
Gene Ontology (GO) analysis was performed on 1196 DEGs (Figure S1), revealing their enrichment in 45 GO_classify2. The top three categories of “cellular component” were cell (920 DEGs), cell part (919 DEGs), and cellular process (681 DEGs). The “biological processes” domain contained the largest number of DEGs, with the top 10 most significant classes (Figure 2C) including pectinesterase activity (GO: 0030599), tricarboxylic acid cycle (GO: 0006099), pectin catabolic process (GO: 0045490), and extracellular region (GO: 0005576). We identified 55 genes; 27 genes were not expressed in female flowers, whereas two (LOC115718471 and LOC115716855) were not expressed in male flowers (Table S2).
Next, the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of 537 DEGs (Figures 2D and S2) revealed enrichment in signal transduction (36 DEGs), biosynthesis of secondary metabolites (38 DEGs), and carbohydrate metabolism (111 DEGs). Secondary metabolite synthesis included the phenylpropane biosynthesis pathway (ko00940) (31 DEGs), flavone and flavonol biosynthesis (ko00944) (3 DEGs), flavonoid biosynthesis (ko00941) (10 DEGs), stilbenoid, diarylheptanoid, and gingerol biosynthesis (ko00945) (11 DEGs), and the MAPK signaling pathway (ko04016) (17 DEGs). In summary, female and male flowers demonstrated significant differences in gene expression. These genes regulate the differential secretion of metabolites in male and female plants and influence their environmental adaptability through signal transduction and environmental responses.
Identification of sex-determination genes
We identified 149 DEGs that could be associated with the sexual differentiation of female and male flowers; 72 were related to flower organs (Table S3), whereas 50 were associated with pollen growth, development, maturation, and regulation. In male flowers, 42 DEGs were upregulated. 13 DEGs were not expressed in female flowers, and the other 29 DEGs were downregulated. The remaining eight DEGs were highly expressed in female flowers. One DEG (LOC115709438) was associated with stamen development. Additionally, 21 DEGs were related to embryo development: 15 were highly expressed in female flowers, four were inhibited, and two were not expressed. In male flowers, six were highly expressed, 13 were inhibited, and two were not expressed. Two DEGs (LOC115700786 and LOC115708058) were associated with embryo sac and pollen development. SPH5 (LOC115721982) was responsible for rejecting self-pollination and was highly expressed only in male flowers (Table S2).
We also identified 77 DEGs responsible for sexual differentiation, specifically participating in hormone biosynthesis, signal transduction, catabolism, and regulation (Table S4). Of these, 31 were highly expressed in male flowers and suppressed in female flowers, whereas the reverse was true for the remaining 46. Among 77 DEGs, 46 DEGs were associated with auxin, 9 were related to gibberellin, 23 were related to ethylene, and 14 were related to cytokinin. LOC115702452 was associated with three hormones other than CTK, and 12 DEGs were associated with two hormones.
Intersexual differences in cannabinoid and terpene content
The main metabolites found in hemp are cannabinoids, terpenes, and alkaloids. Cannabinoids were particularly abundant (a quarter of all metabolites). After measuring six common cannabinoids (cannabidiol, CBD; cannabidivarin, CBDV; cannabidiolic acid, CBDA; tetrahydrocannabivarin, THCV; tetrahydrocannabinol, THC; cannabinol, CBN), we observed that the contents of CBD, CBDV, CBN, and THC were significantly higher in female flowers than in male flowers (Figure 3D). Additionally, CBDA and THCV contents were significantly higher in male flowers than in female flowers (Figure 3D). Finally, CBD was highest in female flowers, being 16.88 times the CBD content in male flowers.
The second most abundant metabolite after cannabinoids was terpenes, the source of cannabis’s unique aroma. Their antioxidant and anti-inflammatory effects synergize and complement cannabinoids.35 Metabolomic sequencing uncovered 28 differentially abundant terpenoid compounds in female and male flowers (Table 1). Fourteen were more abundant in female flowers than in male flowers, whereas the other 14 were richer in male flowers. Sesquiterpenoids (16 subtypes) were the most abundant terpenoids, whereas piperoic acid and beta-farnesene contents were high in both female and male flowers; piperoic acid was even more elevated in female flowers.Metabolites Subclass Average (XF) Average (CF) log2FoldChange 3D,7D,11D-Phytanic acid Diterpenoids 11778116.79 6697.69 10.78016 Annosquamosin B Diterpenoids 9665044.76 850444.91 3.50649 Sagittariol Diterpenoids 6072231.37 552448.64 3.45831 Sugiol Diterpenoids 70981.58 2280254.07 −5.00561 3L,7D,11D-Phytanic acid Diterpenoids 7090.82 1532524.10 −7.75574 3-(2-Hydroxy-4-methylphenyl)-2- butanone Monoterpenoids 25918.00 4676748.59 −7.49541 Dihydrocarvone Monoterpenoids 2765855.28 820167.75 1.75373 Piperoic acid Sesquiterpenoids 269067159.50 595832443.30 −1.14694 beta-Farnesene Sesquiterpenoids 108091083.80 45858409.11 1.23699 Armillarin Sesquiterpenoids 23690640.95 44382489.05 −0.90567 (4E,9a)-9-(3-Methyl-2E- pentenoyloxy)-4,10(14)-oplopadien- 3-one Sesquiterpenoids 279180.52 9175276.98 −5.03848 11′-Carboxy-alpha-tocotrienol Sesquiterpenoids 5880223.49 1834.88 11.64597 9alpha-(3-Methyl-2E-pentenoyloxy)-4S-hydroxy-10(14)-oplopen-3-one Sesquiterpenoids 379231.79 8152925.49 −4.42617 6-Angeloylfuranofukinol Sesquiterpenoids 219330.34 3754380.89 −4.09740 Gossyvertin Sesquiterpenoids 5917646.07 1438623.07 2.04033 Tricyclodehydroisohumulone Sesquiterpenoids 1106155.31 4403164.66 −1.99299 trans,trans-Farnesol Sesquiterpenoids 2902010.87 77347.94 5.22955 Gossypol Sesquiterpenoids 3241810.37 704375.12 2.20238 4,8-Diacetyl-T2-tetrol Sesquiterpenoids 208360.71 2506415.29 −3.58847 Acoragermacrone Sesquiterpenoids 868485.63 2853159.20 −1.71599 Zedoarondiol Sesquiterpenoids 2419854.00 528246.51 2.19564 2-Angeloyl-9-(3-methyl-2E- pentenoyl)-2b,9a-dihydroxy- 4Z,10(14)-oplopadien-3-one Sesquiterpenoids 2206702.18 460309.23 2.26122 Armillyl orsellinate Sesquiterpenoids 8547.65 1672261.93 −7.61206 Fasciculol C Triterpenoids 2914511.77 2956.10 9.94534 Ganoderic acid H Triterpenoids 3198766.04 24.18 17.01342 Reticulataxanthin Triterpenoids 70771.22 2270579.68 −5.00375 Neochlorogenin Triterpenoids 1881862.52 76.22 14.59156 Protobassic acid Triterpenoids 1780406.11 3829.12 8.86098
The differences in cannabinoid and terpene synthesis in female and male C. sativa flowers
Cannabinoid and terpene synthesis share the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway (Figure 5A). Cannabinoid precursors are geranyl diphosphate (GPP) and olivetolic acid (OLA); the former is produced via the MEP pathway and the latter via polyketone synthesis. Lipoxygenase (LOX) and acyl-activating enzymes (AAEs) are the key enzymes during polyketide synthesis. The metabolic precursors of terpenes are produced via the MEP or mevalonate (MVA) pathways. The first key enzyme of the MEP pathway is 1-deoxy-D-xylulose-5-phosphate synthase (DXPS). Isopentenyldiphosphate (IPP) and dimethylallyldiphosphate (DMAPP) are condensed to GPP by geranyl diphosphate synthase (GPPS), an isoprene diphosphate synthase (IDS) that determines terpenoid type. Terpene dehydrogenases (TPS) then act on GPP, FPP, and GGPP to form monoterpenes, sesquiterpenes, and diterpenes, respectively. The MVA pathway intermediate mevalonate-5P can be converted into various isoprenoids that play important roles in cell structure and function.37
We identified CsDXPS1 (LOC115722576), CsLOX2 (LOC115720530), CsLOX1.5 (LOC115724062), CsAAE18 (LOC115722340), CsAAE6-1 (LOC115695955), CsAAE6-2 (LOC115724480), CsGGR (LOC115725388), CsAAT (LOC115699135), and CsMVD2 (LOC115705753) involved in the synthesis pathways of terpenes and cannabinoids (Figure 5A). Except for CsAAE6-1, CsAAT, and CsMVD2, all the identified genes were highly expressed in female flowers (Figure 5B). CsGGR (LOC115725388) was associated with multiple pathways, including terpenoid backbone biosynthesis, sesquiterpenoid and triterpenoid biosynthesis, monoterpenoid biosynthesis, diterpenoid biosynthesis, and indole diterpene alkaloid biosynthesis (Figure S4). We also discovered that one DAM (Mevalonate-5P) exhibited elevated accumulation in male flowers, affecting terpene synthesis. These DEGs and DAMs are the likely intersexual variation sources in the 28 terpenes and cannabinoids we identified.
Discussion
Determinants of sex expression and consequences for medicinal properties in male and female plants
Auxin, gibberellin, cytokinin, and ethylene all play critical regulatory roles in plant sex differentiation. Auxin primarily functions in plant cell elongation and division, as well as the promotion of female traits.38 Similarly, ethylene and cytokinin promote female floral bud differentiation.39,40 In contrast, gibberellin generally inhibits flowering and promotes male differentiation41,42 (although they appear to trigger pistil development in corn43). Given the morphological differences between female and male C. sativa flowers, we uncovered DEGs related to sex differentiation, specifically 77 genes associated with major plant hormones (auxin, gibberellin, cytokinin, ethylene) and their biosynthesis pathways.44 First, the citric acid cycle provides precursor substances and energy for plant hormone biosynthesis.45 We also observed ABC transporter upregulation, crucial for development processes (e.g., gametogenesis, germination, and organ formation), given their function in transporting essential products throughout the plant.46 ABCB1 mediates auxin transport. Meanwhile, ABCC10 is directly involved in the transport of the auxin precursor indole-3-butyric acid (IBA). Both ABCB1 and ABCC10 play crucial roles in plant growth and development.47,48These hormones and genes may contribute to the sex differences between female and male C. sativa flowers.
Cannabinoids and terpenes are the most important components in medicinal and industrial C. sativa. In this study, we confirmed previous research22,23,24 and demonstrated that female and male C. sativa differ significantly in cannabinoid and terpene content. Particularly, female plants have 16.88 times the amount of CBD as male plants. Because CBD is an important medicinal ingredient, along with piperoic acid and sugiol, the higher concentrations in female plants indicate stronger medicinal applications than in male plants, this is consistent with the results of previous studies.24 Therefore, C. sativa cultivation should target female-only or female-dominant varieties, if the primary goal of cultivation is to maximize the plant’s medicinal properties, particularly CBD production. Furthermore, we found 9 DEGs and 1 DAM in the synthesis of cannabinoids and terpenes (Figure 5B). They specifically promote and inhibit the cannabinoid and terpene synthesis, resulting in differences in medicinal functions between male and female C. sativa, providing reference genes for the targeted breeding and selection of medicinal cannabis.
Limitations of the study
Cannabis sativa has considerable economic value as an oil, fiber, and medicinal source. Female and male plants exhibit distinct morphology that influences their applications. To elucidate the sex-biased genes and metabolic disparities underlying these differences, we employed integrated transcriptomic and metabolomic profiling of flowers. The principal chemotypic divergence resides in cannabinoids and terpenoids: we found 9 DEGs and 1 DAM in the synthesis of cannabinoids and terpenes. We infer that these genes indirectly modulate sexual dimorphism in cannabinoid and terpene content; however, the precise regulatory mechanisms remain to be experimentally dissected. We also found that two TF families are particularly important players in trichome and plant epidermal hair development. One notable bHLH member we found was the MYC4 (LOC115708126), and the main MYB member we found was CsMYB49 (LOC115708954). Available data reflect the clear importance of TFs in regulating plant terpene and cannabinoid secretion, yet the molecular details by which these TFs govern glandular-trichome secretion require future investigation. Finally, C. sativa also offers oil- and fiber-utilization potential; the present study focused exclusively on its medicinal attributes, while oil- and fiber-related traits will be explored in future research.
Resource availability
Lead contact
Requests for further information and resources should be directed to and will be fulfilled by the lead contact, Ying Xu, E-mail: xuying0420@163.com.
Materials availability
This study did not generate new, unique reagents.
Data and code availability
- •Data: The raw sequence data reported in this article have been deposited in the Genome Sequence Archive (Genomics, Proteomics & Bioinformatics 2025) in the National Genomics Data Center (Nucleic Acids Res 2025), China National Center for Bioinformation/Beijing Institute of Genomics, Chinese Academy of Sciences (GSA: CRA036554) that are publicly accessible at https://ngdc.cncb.ac.cn/gsa/search?searchTerm=CRA036554. Accession numbers are listed in the key resources table.
- •Code: This article does not report original code.
- •Any additional information required to reanalyze the data reported in this article are available from the lead contact upon request.
Acknowledgments
This study was financially supported by the Germplasm Resources Protection Project and the Central Public-interest Scientific Institution Basal Research Fund (1610242024015). We sincerely thank Editage (www.editage.cn) for English language editing.
Declaration of interests
The authors declare there is no conflict of interest in this article.
STAR★Methods
Key resources table
| REAGENT or RESOURCE | SOURCE | IDENTIFIER |
|---|---|---|
| Biological samples | ||
| Long 6 | the National Germplasm MId-term GenBank of Bast Fiber Crops,in the Institute of Bast Fiber Crops of the Chinese Academy of Agriculture Sciences | N/A |
| Chemicals, peptides, and recombinant proteins | ||
| CBD standards | Sigma Aldrich (St. Louis, USA) | C-045 |
| CBDA standards | Sigma Aldrich (St. Louis, USA) | C-144 |
| CBDV standards | Sigma Aldrich (St. Louis, USA) | C-199 |
| THC standards | Sigma Aldrich (St. Louis, USA) | T-005 |
| THCV standards | Sigma Aldrich (St. Louis, USA) | T-111 |
| CBN standards | Sigma Aldrich (St. Louis, USA) | C-093 |
| Deposited data | ||
| Transcriptome sequencing data | This article | https://ngdc.cncb.ac.cn/gsa/search?searchTerm=CRA036554 |
| Software and algorithms | ||
| Progenesis QI version 3.0 | Nonlinear Dynamics, Newcastle, UK | https://www.nonlinear.com/progenesis/qi/v3.0/download/ |
| DESeq2 V1.22.2 | Ref. 68 | https://bioconductor.org/packages/release/bioc/html/DESeq2.html |
| R software V 3.2.0 | R Development Core Team | https://cran.r-project.org/ |
Experimental model and study participant details
The industrial C. sativa variety Long 6 was provided by the National Germplasm Mid-term GenBank of Bast Fiber Crops in the Institute of Bast Fiber Crops of the Chinese Academy of Agriculture Sciences. This particular variety represents a medicinal-grade industrial hemp with characteristically high CBD content. For propagation in artificial climate-controlled room, lateral branches (approximately 12 cm) of female and male plants were cultivated in a plastic basin (diameter = 32 cm) and cultured in an artificial culture chamber maintained at 50–60% relative humidity and 25 ± 2 °C. Light conditions were 33,000 lux, with 18 h of light and 6 h of darkness. During the growth period, cuttings were watered once every 3 days to keep the soil moist. The seedling matrix (pH 5.5–7.0, organic matter content ≧20%) was acquired from Hunan Xianghui Agricultural Science and Technology Development. Detailed methods followed a published protocol.61 Compound fertilizer, with a composition of 30 g Pot-1, 30% N, 10% K, and 10% P, was applied at 14 days after the emergence of the first new leaf. After 4 weeks of vegetative growth, female and male plants of approximately 60 cm in height were selected and transferred to a closed artificial climate chamber. The light-dark cycle was set to 12 h of light and 12 h of darkness, whereas the temperature and humidity remained unchanged. After 28 days of cultivation, the light-dark cycle was adjusted to 8 h of light and 16 h of darkness to induce reproductive growth and flowering. Female and male plants entered the peak bloom period after 26 days and 35 days, respectively. All samples were obtained during the peak bloom period to ensure biological consistency. The flower sampling site was approximately 2 cm from the apex. Flowers were photographed before sample collection for cannabinoid, transcriptome, and metabolome analyses.
For cannabinoid determination, female plants were sampled at 5 cm from the top of the flower, and male plants at 3–8 cm from the top (5 g per sample); sampling was repeated three times. For transcriptome and metabolome analysis, a separate 1 g of plant material (from the same positions) was obtained. Samples were put into a 5 mL freezer tube and subsequently immersed in liquid nitrogen for freezing. Transcriptome analysis was performed in triplicate per sex for a total of six samples. Metabolomic analysis was repeated eight times per sex for 16 samples.
Method details
Cannabinoid extraction and analysis
Female and male flower samples were collected, dried at 85 °C until they reached a constant weight, and ground before methanol (4 mL) was added. The mixture was processed using ultrasonic extraction for 10 min and then stood for 1 h. Next, the samples underwent centrifugation at 4000 r/min for 5 min, after which the supernatant was transferred to a 10 mL volumetric flask for calibration. Using a syringe, 1 mL of supernatant was filtered through a 0.45 μm microporous membrane, transferred to a 2 mL liquid phase sampling bottle, and further processed by high-performance liquid chromatography (HPLC)62 using an SHIMADZU C18 column (length 250 mm, inner diameter 4.6 mm, particle size 5 μm). Mobile phase A used 0.1% acetic acid, and mobile phase B used acetonitrile. The settings were as follows: column temperature, 25 °C; wavelength, 220 nm; flow rate, 0.800 mL/min; and injection volume, 10 μL. Six types of cannabinoids were measured (mg/L): CBD, CBDV, CBDA, THC, THCV, and CBN. Samples were analyzed in triplicate. Cannabinoid content was expressed as a mass percentage, and calculations followed published procedures.61 All cannabinoid standards (Ceriliant, USA) were purchased from Sigma Aldrich (St. Louis, USA).
RNA extraction, sequencing, and DEG analysis
Total RNA extraction and sequencing of six samples (CF-1, CF-2, CF-3, XF-1, XF-2, and XF-3; CF = female flower and XF = male flower) were performed using an RNAprep Pure Plant Plus Kit (DP441, Tiangen Biotech, China). Libraries were established from extracted RNA using the VAHTS Universal V5 RNA-Seq Library Preparation Kit (Vazyme, China), followed by transcriptome analysis. All these procedures were carried out by OE Biotechnology (Shanghai, China) using an Illumina HiSeq 2500 sequencer. The 150 bp paired-end raw reads were cleaned and aligned against the reference genome CS1064 in HISAT 2.65 Read counts per gene were determined using HTSeq.66 Biological duplication and pairing difference analysis of samples were conducted on the DESeq267 V1.22.2. The read counts of each gene across all samples were first normalized (with baseMean values employed for expression-level estimation), fold changes were computed, and differential significance was tested via the negative-binomial (NB) Wald test. The q-value for each gene was derived by subjecting its p-value to Benjamini-Hochberg FDR correction. Differentially expressed genes were those with q-values ≤0.05 and |log2FoldChange| >1. Hierarchical cluster analysis of DEGs was conducted on R software (V 3.2.0). Functional analyses were performed with GO and KEGG databases.
Quantification and statistical analysis
Statistical analyses were performed with SPSS Statistics 26.0 (SPSS Inc., Chicago, IL) and GraphPad Prism 10. Results are expressed as mean ± SE (n ≥ 3). Student’s t-tests determined significance, with p < 0.05 set as the threshold.