Astragalus membranaceus (A. membranaceus), a well-known traditional herbal medicine, has been widely used in ailments for more than 2000 years. The main bioactive compounds including flavonoids, triterpene saponins and polysaccharides obtained from A. membranaceus have shown a wide range of biological activities and pharmacological effects. These bioactive compounds have a significant role in protecting the liver, immunomodulation, anticancer, antidiabetic, antiviral, antiinflammatory, antioxidant and anti-cardiovascular activities. The flavonoids are initially synthesized through the phenylpropanoid pathway, followed by catalysis with corresponding enzymes, while the triterpenoid saponins, especially astragalosides, are synthesized through the universal upstream pathways of mevalonate (MVA) and methylerythritol phosphate (MEP), and the downstream pathway of triterpenoid skeleton formation and modification. Moreover, the Astragalus polysaccharide (APS) possesses multiple pharmacological activities. In this review, we comprehensively discussed the biosynthesis pathway of flavonoids and triterpenoid saponins, and the structural features of polysaccharides in A. membranaceus. We further systematically summarized the pharmacological effects of bioactive ingredients in A. membranaceus, which laid the foundation for the development of clinical candidate agents. Finally, we proposed potential strategies of heterologous biosynthesis to improve the industrialized production and sustainable supply of natural products with pharmacological activities from A. membranaceus, thereby providing an important guide for their future development trend.

Apocynum venetum is a semi-shrubby perennial herb that not only prevents saline–alkaline land degradation but also produces leaves for medicinal uses. Although physiological changes during the seed germination of A. venetum in response to salt stress have been studied, the adaptive mechanism to salt conditions is still limited. Here, the physiological and transcriptional changes during seed germination under different NaCl treatments (0–300 mmol/L) were examined. The results showed that the seed germination rate was promoted at low NaCl concentrations (0–50 mmol/L) and inhibited with increased concentrations (100–300 mmol/L); the activity of antioxidant enzymes exhibited a significant increase from 0 (CK) to 150 mmol/L NaCl and a significant decrease from 150 to 300 mmol/L; and the content of osmolytes exhibited a significant increase with increased concentrations, while the protein content peaked at 100 mmol/L NaCl and then significantly decreased. A total of 1967 differentially expressed genes (DEGs) were generated during seed germination at 300 mmol/L NaCl versus (vs.) CK, with 1487 characterized genes (1293 up-regulated, UR; 194 down-regulated, DR) classified into 11 categories, including salt stress (29), stress response (146), primary metabolism (287), cell morphogenesis (156), transcription factor (TFs, 62), bio-signaling (173), transport (144), photosynthesis and energy (125), secondary metabolism (58), polynucleotide metabolism (21), and translation (286). The relative expression levels (RELs) of selected genes directly involved in salt stress and seed germination were observed to be consistent with the changes in antioxidant enzyme activities and osmolyte contents. These findings will provide useful references to improve seed germination and reveal the adaptive mechanism of A. venetum to saline–alkaline soils.

The construction level of artificial grassland is an important index of the development degree of grassland animal husbandry. Therefore, improving the productivity level of artificial grassland and promoting the sustainable utilization of artificial grassland have become important tasks that need to be urgently addressed. There have been numerous studies on the effects of monoculture on the soil microbial community structure in artificial grassland, but there is limited research on the effects of mixed sowing on the soil microbial community structure and the related patterns. In this study, Elymus nutans (En), Festuca sinensis (Fs), Avena sativa (As), and Poa pratensis (Pp) were used as common herbage materials in an alpine grassland pastoral area of the eastern Tibetan Plateau. Multi-density monoculture and mixed seeding were employed to establish artificial grassland communities with varying structures. By comparing the soil microbial community structure of the differently treated artificial planting grass, degraded grassland with bald spots, and natural grassland, it was confirmed that plant community diversity significantly influences the microbial community structure. The high-density planting treatment of multiple forage grasses had a more pronounced impact on the soil microbial community structure compared to that of the high-density planting treatment of a single variety of forage grass. The soil microbial community diversity index of the four mixed-planting treatments was higher than those of the other artificial grassland treatments and the natural grassland treatments, and the soil microbial community structure was most similar to that of the natural grassland. Avena sativa planting increased the abundance of Actinobacteria and Basidiomycota and decreased the number of Acidobacteria by increasing the soil pH value. The AFP (As+Fs+Pp) treatment reduced the proportion of Mortierellomycota in the soil by decreasing the content of available phosphorus. The AEFP (As+En+Fs+Pp) treatment increased the number of Proteobacteria by raising the soil total phosphorus content and reduced the abundance of Acidobacteria by lowering the soil pH value. Additionally, a machine learning method was used to evaluate the comprehensive performance of 21 artificial grassland treatments on nine soil physical and chemical properties. It was found that the AEFP mixed-planting and high-density planting treatments had the greatest improvement effect on the nine soil physical and chemical properties, which was conducive to sustainable land use.

Angelica sinensis is a perennial herbaceous species mainly cultivated in the Gansu, Yunnan, and Qinghai provinces of China, and its dried roots have been widely used for nourishing blood and harmonizing vital energy, largely relying on its bioactive compounds (e.g., alkylphthalides, polysaccharides, and flavonoids). In recent years, viral diseases have been suspected to be present in A. sinensis in field cultivation. In order to reveal the infection status and causes, a survey and the identification of viral diseases and their influence on the yield and quality of A. sinensis were conducted in four different counties of Gansu province. The results showed viral disease rates of ca. 21% to 37% for potato virus Y (PVY) and tomato mosaic virus (ToMV), as well as ca. 2.8- to 8.9-fold decreases in root yield on a unit-area basis; meanwhile, the contents of the main bioactive compounds (i.e., ferulic acid, ligustilide, and polysaccharides) were significantly lower in the virus-infected plants (VIPs) compared with the virus-free plants (VFPs); there were significant positive relationships of the viral disease rate with planting density and expression levels of the PVY-coat protein (CP) and ToMV-CP genes (p < 0.01). The above-mentioned observations indicate that it is necessary and urgent to take measures (e.g., controlling plant density, rational rotation, and using virus-free seedlings) to prevent the spread of plant viruses.