Trichome-Specific Analysis and Weighted Gene Co-Expression Correlation Network Analysis (WGCNA) Reveal Potential Regulation Mechanism of Artemisinin Biosynthesis in Artemisia annua .

Trichomes are attractive cells for terpenoid biosynthesis and accumulation in Artemisia annua . However, the molecular process underlying the trichome of A. annua is not yet fully elucidated. In this study, an analysis of multi-tissue transcriptome data was performed to examine trichome-specific expression patterns. A total of 6646 genes were screened and highly expressed in trichomes, including artemisinin biosynthetic genes such as amorpha-4,11-diene synthase ( ADS ) and cytochrome P450 monooxygenase ( CYP71AV1 ). Mapman and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that trichome-specific genes were mainly enriched in lipid metabolism and terpenoid metabolism. These trichome-specific genes were analyzed by a weighted gene co-expression network analysis (WGCNA), and the blue module linked to terpenoid backbone biosynthesis was determined. Hub genes correlated with the artemisinin biosynthetic genes were selected based on TOM value. ORA , Benzoate carboxyl methyltransferase ( BAMT ), Lysine histidine transporter-like 8 ( AATL1 ), Ubiquitin-like protease 1 ( Ulp1 ) and TUBBY were revealed as key hub genes induced by methyl jasmonate (MeJA) for regulating artemisinin biosynthesis. In summary, the identified trichome-specific genes, modules, pathways and hub genes provide clues and shed light on the potential regulatory mechanisms of artemisinin biosynthesis in trichomes in A. annua .