The study on the extraction conditions, purification, and biological activity of slash pine ( Pinus elliottii. ) is important for the development of slash pine resources. The optimal process conditions for the extraction of slash pine polysaccharide (SPP) were determined, resulting in a liquid-solid ratio of 66.94 mL/g, extraction temperature of 83.74 °C and extraction time of 2.56 h by using the response surface methodology, and the yield of SPP was 5.99% under the optimized conditions. Following the purification of SPP, the SPP-2 component was obtained and its physicochemical properties, functional group composition, antioxidant capacity, and moisturizing capacity were determined. Structural analysis suggested that SPP-2 has a molecular weight of 118.407 kDa, and was composed of rhamnose, arabinose, fucose, xylose, mannose, glucose, and galactose in a ratio of 5.98: 14.34: 1: 1.75: 13.50: 3.43: 15.79. The antioxidant activity analysis showed that SPP-2 has good free radical scavenging activity, and it was also found to have in vitro moisturizing activity and low irritation. These results suggest that SPP-2 has the potential for applications in the pharmaceutical, food, and cosmetic industries.
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.
危险品化学品经营许可证（带存储）