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Phlomoides rotata, a traditional medicinal plant, is commonly found on the Tibetan Plateau at altitudes of 3100–5200 m. Its primary active medicinal compounds, flavonoids and phenylethanol glycosides (PhGs), exhibit various pharmacological effects, including hemostatic, anti-inflammatory, antitumor, immunomodulatory, and antioxidant activities. This study analyzed flavonoid and PhG metabolites in the roots of P. rotata collected from Henan County (HN), Guoluo County (GL), Yushu County (YS), and Chengduo County (CD) in Qinghai Province. A total of differentially abundant metabolites (DAMs) including 38 flavonoids and 21 PhGs were identified. Six genes (UFGT1, CHS1, COMT2, C4H3, C4H8, and C4H5) and four enzymes (4CL, C4H, PPO, and ALDH) were found to play key roles in regulating flavonoid and PhG biosynthesis in P. rotata roots. With increasing altitude, the relative content of 15 metabolites, the expression of seven genes, and the activity of four enzymes associated with flavonoid and PhG metabolism increased. These findings enhance our understanding of the regulatory mechanisms of flavonoid and PhG metabolism in P. rotata and provide insights into the potential pharmaceutical applications of its bioactive compounds. [ABSTRACT FROM AUTHOR]

Lycium chinense is acknowledged for its substantial nutritional benefits, particularly attributed to the high levels of ascorbic acid (AsA) found in its fruits. The "Mengqi No.1" variety of L. chinense, which is cultivated in Qinghai, is known for its high yield and exceptional quality. We utilized the "Mengqi No.1" variety as experimental materials and combined metabolomic, transcriptomic, and physiological analyses to investigate the metabolites, genes, and enzymes related to AsA metabolism in L. chinense fruits. The results revealed nine differential metabolites associated with AsA metabolism in L. chinense fruits across three stages, including 1D-Myo-Inositol-1,4-Bisphosphate, D-Fructose, L-(+)-Arabinose, I-Inositol, L-Arabinitol, D-Galactose-1-P, lactose, α-D-Glucose, and D-Glucose-6-P. Notably, the contents of D-Glucose-6-P, D-Galactose-1-P, and D-Fructose were increased as the fruit developed. Additionally, fresh weight, longitudinal length, and radial width were increased, while the contents of AsA and DHA were decreased. GalDH and DHAR are critical enzymes for the accumulation of AsA and DHA, exhibiting positive correlation coefficient. Furthermore, PMM1, PMM5, GME2, and GME3 were identified as key regulatory genes in the L-Galactose pathway of AsA synthesis, influencing D-Galactose-1-P, D-Glucose-6-P, α-D-Glucose, and D-Fructose. DHAR1 and DHAR2 are considered key positive regulator genes of AsA and DHA in the AsA-GSH cycle. However, the majority of genes (nine) act as negative regulators of AsA and DHA. These findings provide a foundation for the understanding of the regulatory mechanism of AsA metabolism in L. chinense fruits and offer insights into the utilization of AsA from L. chinense. [ABSTRACT FROM AUTHOR]

Phlomoides rotata is a traditional Chinese herbal medicine that grows in the Qinghai–Tibet Plateau region at a 3100–5000 m altitude. Iridoid compounds are the main active compounds of the P. rotata used as medical ingredients and display anti-inflammatory, analgesic, and hepatoprotective properties. To better understand the biological mechanisms of iridoid compounds in this species, we performed a comprehensive analysis of the transcriptome and metabolome of P. rotata leaves from four different regions (3540–4270 m). Global metabolome profiling detected 575 metabolites, and 455 differentially accumulated metabolites (DAMs) were detected in P. rotata leaves from the four regions. Eight major DAMs related to iridoid metabolism in P. rotata leaves were investigated: shanzhiside methyl ester, 8-epideoxyloganic acid, barlerin, shanzhiside, geniposide, agnuside, feretoside, and catalpin. In addition, five soil physical and chemical indicators in P. rotata rhizosphere soils were analyzed. Four significant positive correlations were observed between alkaline nitrogen and geniposide, exchangeable calcium and geniposide, available potassium and shanzhiside, and available phosphorus and shanzhiside methyl ester. The transcriptome data showed 12 P. rotata cDNA libraries with 74.46 Gb of clean data, which formed 29,833 unigenes. Moreover, 78.91% of the unigenes were annotated using the eight public databases. Forty-one candidate genes representing 23 enzymes involved in the biosynthesis of iridoid compounds were identified in P. rotata leaves. Moreover, the DXS1, IDI1, 8-HGO1, and G10H2 genes associated with iridoid biosynthesis were specifically expressed in P. rotata. The integration of transcriptome and metabolome analyses highlights the crucial role of soil physical and chemical indicators and major gene expression related to iridoid metabolism pathways in P. rotata from different areas. Our findings provide a theoretical foundation for exploring the molecular mechanisms underlying iridoid compound accumulation in P. rotata. [ABSTRACT FROM AUTHOR]