Utilizing salt-tolerant plants is a cost-effective strategy for agricultural production on salinized land. However, little is known about the mechanism of dandelion (Taraxacum mongolicum Hand.-Mazz.) in response to saline stress and caffeic acid biosynthesis. We investigated the morphological and physiological variations of two dandelions, namely, “BINPU2” (dandelion A) and “TANGHAI” (dandelion B) under gradient NaCl concentrations (0, 0.3%, 0.5%, 0.7%, and 0.9%), and analyzed potential mechanisms through a comparison analysis of transcriptomes in the two dandelions. Dandelion A had a high leaf weight; high ρ-coumaric acid, caffeic acid, ferulic acid, and caffeoyl shikimic acid contents; and high activities of POD and Pro. The maximum content of four kinds of phenolic acids mostly occurred in the 0.7% NaCl treatment. In this saline treatment, 2468 and 3238 differentially expressed genes (DEGs) in dandelion A and B were found, of which 1456 and 1369 DEGs in the two dandelions, respectively, showed up-regulation, indicating that more up-regulated DEGs in dandelion A may cause its high salt tolerance. Further, Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that dandelion salt response and caffeic acid metabolism were mainly enriched in the phenylpropanoid biosynthesis pathway (ko00940) and response to ethylene (GO: 0009723). The caffeic acid biosynthesis pathway was reconstructed based on DEGs which were annotated to PAL, C4H, 4CL, HCT, C3′H, and CSE. Most of these genes showed a down-regulated mode, except for parts of DEGs of 4CL (TbA05G077650 and TbA07G073600), HCT (TbA03G009110, TbA03G009080, and novel.16880), and COMT (novel.13839). In addition, more up-regulated transcription factors (TFs) of ethylene TFs in dandelion A were found, but the TFs of ERF104, CEJ1, and ERF3 in the two dandelions under saline stress showed an opposite expression pattern. These up-regulated genes could enhance dandelion salt tolerance, and down-regulated DEGs in the caffeic acid biosynthesis pathway, especially CSE (TbA08G014310) and COMT (TbA04G07330), could be important candidate genes in the synthesis of caffeic acid under saline stress. The above findings revealed the potential mechanisms of salt response and caffeic acid metabolism in dandelion under saline stress, and provide references for salt-tolerant plant breeding and cultivation on saline–alkali land in the future.

This study explores the variation in the content of major phenolic acid components in dandelions from different regions, and the potential molecular mechanisms underlying their anti-inflammatory activity. High-performance liquid chromatography (HPLC) was employed to analyze dandelion leaves collected from four different regions in Hebei Province across eight harvest periods. The results indicated that chlorogenic acid had the highest content (0.334–1.963%), suggesting that this could be a key evaluation index for dandelion leaf harvesting. Further molecular docking and molecular dynamics simulations revealed that chlorogenic acid, caffeic acid, and chicoric acid could competitively bind to the key amino acid residues (e.g., PHE-151, ILE-117) of the MD-2 protein, thereby preventing the insertion of lipopolysaccharides (LPSs) and inhibiting the formation of the TLR4/MD-2 complex, which elucidates their potential anti-inflammatory mechanism. Moreover, environmental factors significantly influenced the accumulation of phenolic acids in dandelions, with temperature, precipitation, soil pH, and altitude showing correlations with the content variation of major phenolic acids. These findings provide a scientific basis for determining the optimal harvesting period of dandelion leaves, and offer new insights into the anti-inflammatory mechanisms of phenolic acids.

Creating high-quality and salt-tolerant plant germplasm is an effective strategy to improve the utilization of saline-alkali land. Salt-induced callus mutation was used to create dandelion germplasm and mutant dandelion calluses were obtained under NaCl concentrations of 0.8%, 1%, and 1.2% with the identification of random amplified polymorphic DNA (RAPD) markers. A new dandelion line, “Binpu 2”, selected from the progenies of dandelion tissue culture plantlets that originated from callus treated under 0.8% NaCl, was evaluated in light of its morphological characteristics, bioactive components, and antitumor functions. Results showed that the plant shape of “Binpu 2”was nearly upright; its cichoric acid content was 6.7 mg/g, which was 39.6% and 36.7% higher than its mother plant and local dandelion cultivar, respectively; its leaf water extracts of 0.2 g/mL had a significant inhibitory effect on cell polarity disruption-induced cell migration without affecting drosophila normal growth, revealed by the strong inhibitory effect on tumor cell migration, the increased level of MMP1 and β-Integrin, and the reduced E-cadherin expression. Our results suggested that “Binpu 2” originated from salt-induced mutant performed better than its mother plant and processed strong antitumor function, which was suitable for amplified cultivation in saline-alkali land for food and medicinal industrial development.

Soil salinization hinders plant growth and agricultural production, so breeding salt-tolerant crops is an economical way to exploit saline–alkali soils. However, the specific metabolites and associated pathways involved in salt tolerance of the dandelion have not been clearly elucidated so far. Here, we compared the transcriptome and metabolome responses of 0.7% NaCl-stressed dandelion ‘BINPU2’ (variety A) and ‘TANGHAI’ (variety B). Our results showed that 222 significantly altered metabolites mainly enriched in arginine biosynthesis and pyruvate metabolism according to a KEGG database analysis in variety A, while 147 differential metabolites were predominantly enriched in galactose metabolism and the pentose phosphate pathway in variety B. The transcriptome data indicated that the differentially expressed genes (DEGs) in variety A were linked to secondary metabolite biosynthesis, phenylpropanoid biosynthesis, and photosynthesis–antenna proteins. Additionally, KEGG annotations revealed the DEGs had functions assigned to general function prediction only, post-translation modification, protein turnover, chaperones, and signal transduction mechanisms in variety A. By contrast, the DEGs had functions assigned to variety B as plant–pathogen interactions, phenylpropanoid biosynthesis, and photosynthesis–antenna proteins, including general function prediction, signal transduction mechanisms, and secondary metabolite biosynthesis from the KOG database functional annotation. Furthermore, 181 and 162 transcription factors (TFs) expressed under saline stress conditions specifically were detected between varieties A and B, respectively, representing 36 and 37 TF families. Metabolomics combined with transcriptomics revealed that salt stress induced substantial changes in terpenoid metabolites, ubiquinone biosynthesis metabolites, and pyruvate metabolites, mediated by key enzymes from the glycoside hydrolase family, adenylate esterases family, and P450 cytochrome family at the mRNA and/or metabolite levels. These results may uncover the potential salt-response mechanisms in different dandelion varieties, providing insights for breeding salt-tolerant crop plants suitable for saline–alkali land cultivation.