The hop plant (Humulus lupulus L.) produces several valuable secondary metabolites, such as prenylflavonoid, bitter acids, and essential oils. These compounds are biosynthesized in glandular trichomes (lupulin glands) endowed with pharmacological properties and widely implicated in the beer brewing industry. The present study is an attempt to generate exhaustive information of transcriptome dynamics and gene regulatory mechanisms involved in biosynthesis and regulation of these compounds, developmental changes including trichome development at three development stages, namely leaf, bract, and mature lupulin glands. Using high-throughput RNA-Seq technology, a total of 61.13, 50.01, and 20.18 Mb clean reads in the leaf, bract, and lupulin gland libraries, respectively, were obtained and assembled into 43,550 unigenes. The putative functions were assigned to 30,996 transcripts (71.17%) based on basic local alignment search tool similarity searches against public sequence databases, including GO, KEGG, NR, and COG families, which indicated that genes are principally involved in fundamental cellular and molecular functions, and biosynthesis of secondary metabolites. The expression levels of all unigenes were analyzed in leaf, bract, and lupulin glands tissues of hop. The expression profile of transcript encoding enzymes of BCAA metabolism, MEP, and shikimate pathway was most up-regulated in lupulin glands compared with leaves and bracts. Similarly, the expression levels of the transcription factors and structural genes that directly encode enzymes involved in xanthohumol, bitter acids, and terpenoids biosynthesis pathway were found to be significantly enhanced in lupulin glands, suggesting that production of these metabolites increases after the leaf development. In addition, numerous genes involved in primary metabolism, lipid metabolism, photosynthesis, generation of precursor metabolites/energy, protein modification, transporter activity, and cell wall component biogenesis were differentially regulated in three developmental stages, suggesting their involvement in the dynamics of the lupulin gland development. The identification of differentially regulated trichome-related genes provided a new foundation for molecular research on trichome development and differentiation in hop. In conclusion, the reported results provide directions for future functional genomics studies for genetic engineering or molecular breeding for augmentation of secondary metabolite content in hop.

• MeSH
• flavonoidy biosyntéza   chemie   metabolismus   MeSH
• genová ontologie MeSH
• Humulus chemie   metabolismus   MeSH
• listy rostlin genetika   metabolismus   MeSH
• propiofenony chemie   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• sekvenování transkriptomu MeSH
• terpeny chemie   metabolismus   MeSH
• transkripční faktory metabolismus   MeSH
• transkriptom genetika   MeSH
• trichomy genetika   metabolismus   ultrastruktura   MeSH
• Publikační typ
• časopisecké články MeSH

Plasma membrane (PM) lipid composition and domain organization are modulated by polarized exocytosis. Conversely, targeting of secretory vesicles at specific domains in the PM is carried out by exocyst complexes, which contain EXO70 subunits that play a significant role in the final recognition of the target membrane. As we have shown previously, a mature Arabidopsis trichome contains a basal domain with a thin cell wall and an apical domain with a thick secondary cell wall, which is developed in an EXO70H4-dependent manner. These domains are separated by a cell wall structure named the Ortmannian ring. Using phospholipid markers, we demonstrate that there are two distinct PM domains corresponding to these cell wall domains. The apical domain is enriched in phosphatidic acid (PA) and phosphatidylserine, with an undetectable amount of phosphatidylinositol 4,5-bisphosphate (PIP2), whereas the basal domain is PIP2-rich. While the apical domain recruits EXO70H4, the basal domain recruits EXO70A1, which corresponds to the lipid-binding capacities of these two paralogs. Loss of EXO70H4 results in a loss of the Ortmannian ring border and decreased apical PA accumulation, which causes the PA and PIP2 domains to merge together. Using transmission electron microscopy, we describe these accumulations as a unique anatomical feature of the apical cell wall-radially distributed rod-shaped membranous pockets, where both EXO70H4 and lipid markers are immobilized.

• MeSH
• Arabidopsis chemie   genetika   MeSH
• buněčná membrána chemie   genetika   MeSH
• exocytóza genetika   MeSH
• fosfatidylinositol-4,5-difosfát chemie   metabolismus   MeSH
• fosfatidylseriny chemie   genetika   MeSH
• membránové lipidy genetika   metabolismus   MeSH
• proteiny huseníčku chemie   genetika   MeSH
• trichomy chemie   genetika   MeSH
• vezikulární transportní proteiny chemie   genetika   MeSH
• Publikační typ
• časopisecké články MeSH