Global climate change has increased the frequency and severity of droughts, which may affect the biosynthesis of coniferous terpenes, but the regulatory mechanism is still unclear. We explored the mechanisms of terpenoid regulation in response to drought stress by resolving changes in terpenoid composition and gene expression under drought stress to better understand the expression profile of terpenoid synthesis in slash pine . We obtained three main results: (1) A total of 1393 differentially expressed genes (DEGs) were identified, mainly including MYB, AP2/ERF, WRKY and other transcription factors, which were reported to be associated with plant resistance. Real-time quantitative PCR (RT-qPCR) verified the reliability of transcriptomic data, and the analysis of its results shows a close correlation with the data obtained by RNA-seq. (2) A total of 39 DEGs encoding 7 types of the proteins that were identified in the terpene synthesis pathway; what’s more, TPS (e.g., PITA_24906, PITA_00655, PITA_09277) and CYP720B11 (PITA_22711) showed high expressions in diterpene synthesis. (3) A weighted coexpression network analysis (WGCNA) showed high correlations between levopimaric acid content and module genes expression. Network visualization of the 70 hub genes revealed this high degree of connectivity between PITA_24906 and other genes, suggesting that PITA_24906 might play a regulatory role in levopimaric acid under drought stress. Thus, the results of this study will lead to a better understanding of the defense mechanisms of slash pine and provide a basic reference for the management and genetic improvement of slash pine stands.
Background/Objectives:Acute lung injury (ALI) is a respiratory disorder lacking specific targeted therapy. Our preliminary screening revealed that the ethanol extract of the seeds ofPodocarpus nakaii(EESPN) alleviated the symptoms of ALI in mice. The objectives of this study were to identify the active constituents in EESPN and study the mechanism involved.Methods:Column chromatography was performed to separate the chemical constituents of EESPN. The structures of the isolates were determined via spectroscopic methods. MTT assays, Western blotting, histological analysis, TUNEL assays, immunofluorescence staining, transcriptomic analysis, and quantitative real-time polymerase chain reaction (qRT–PCR) were employed to evaluate the anti-inflammatory activity and to elucidate the potential mechanism of nagilactone C (3, Nag C) in ALI treatment.Results:Twelve compounds were isolated from EESPN and structurally characterized. The structure of podolactone E (1) was confirmed via single-crystal X-ray diffraction. In vitro, Nag C showed potent anti-inflammatory activity in LPS-induced RAW 264.7 cells. Nag C liposomes significantly ameliorated LPS-induced histopathological damage to the lungs, reduced neutrophil infiltration and inflammatory cytokine levels, increased myeloperoxidase (MPO) activity, and promoted apoptosis in mice. In addition to suppressing inflammation, Nag C also significantly suppressed the phosphorylation of the NF-κB, STAT3, and STAT1 proteins.Conclusions:Nag C is an active constituent of EESPN. It may protect against LPS-induced ALI via inhibition of the STAT signaling pathway. Thus, Nag C is a promising lead compound in the development of novel STAT-targeted anti-inflammatory agents.
危险品化学品经营许可证（带存储）