Background/Objectives: Gardeniae Fructus (GF) has been widely used as both food and medicinal purposes for thousands of years, but their antioxidant properties and potential metabolite biomarkers remain unclear. Methods: The purposes of this study were to examine antioxidant activities of 21 GF varieties from different geographical origins in China and identify potential biomarkers of antioxidant properties using an untargeted LC–MS-based metabolomics approach. Results: The results demonstrate that metabolomics had the ability to trace the geographical origins of GF. We found that antioxidant activities varied with different varieties of GF, which was dependent on their chemical compositions. The key chemical categories were obtained as the primary contributors of the antioxidant activity, including prenol lipids, flavonoids, coumarins and derivatives, as well as steroids and steroid derivatives. In addition, adouetine Y, coagulin R 3-glucoside and epicatechin 3-glucoside were identified as potential biomarkers for the antioxidant activity of GF. Conclusions: Therefore, our study sheds light on the metabolic characteristics and biomarkers of the antioxidant properties of GF, contributing to the selection and cultivation of a high antioxidant variety.

Glutathione S-transferases (GSTs) are members of a protein superfamily with diverse physiological functions, including cellular detoxification and protection against oxidative damage. However, there is limited research on GSTs responding to cadmium (Cd) stress. This study classified 46 GST genes in Dendrobium officinale (D. officinale) into nine groups using model construction and domain annotation. Evolutionary analysis revealed nine subfamilies with diverse physical and chemical properties. Prediction of subcellular localization revealed that half of the GST members were located in the cytoplasm. According to the expression analysis of GST family genes responding to Cd stress, DoGST5 responded significantly to Cd stress. Transient expression of DoGST5-GFP in tobacco leaves revealed that DoGST5 was localized in the cytoplasm. DoGST5 overexpression in Arabidopsis enhanced Cd tolerance by reducing Cd-induced H₂O₂ and O₂⁻ levels. These findings demonstrate that DoGST5 plays a critical role in enhancing Cd tolerance by balancing reactive oxygen species (ROS) levels, offering potential applications for improving plant adaptability to heavy metal stress.

Polygonatum cyrtonema (P. cyrtonema) is a valuable rhizome-propagating traditional Chinese medical herb. Polysaccharides (PCPs) are the major bioactive constituents in P. cyrtonema. However, the molecular basis of PCP biosynthesis in P. cyrtonema remains unknown. In this study, we measured the PCP contents of 11 wild P. cyrtonema germplasms. The results showed that PCP content was the highest in Lishui Qingyuan (LSQY, 11.84%) and the lowest in Hangzhou Lin’an (HZLA, 7.18%). We next analyzed the transcriptome profiles of LSQY and HZLA. Through a qRT-PCR analysis of five differential expression genes from the PCP biosynthesis pathway, phosphomannomutase, UDP-glucose 4-epimerase (galE), and GDP-mannose 4,6-dehydratase were determined as the key enzymes. A protein of a key gene, galE1, was localized in the chloroplast. The PCP content in the transiently overexpressed galE1 tobacco leaves was higher than in the wild type. Moreover, luciferase and Y1H assays indicated that PcWRKY31 and PcWRKY34 could activate galE1 by binding to its promoter. Our research uncovers the novel regulatory mechanism of PCP biosynthesis in P. cyrtonema and is critical to molecular-assisted breeding.

Mycorrhizal symbiosis represents a ubiquitous mutualistic relationship in nature, wherein mycorrhizal fungi enhance the host plant’s ability to absorb water and nutrients from the soil. In return, the host plant supplies the fungi with essential nutrients necessary for their metabolic activities. However, research focusing on the regulatory mechanisms governing mycorrhizal symbiosis in Dendrobium officinale remains limited. This study systematically investigates the regulatory mechanisms of mycorrhizal symbiosis on transcriptional synthesis in D. officinale by establishing a mycorrhizal symbiotic system, complemented by phenotypic observation, physiological measurement, and transcriptome sequencing. The results indicate that mycorrhizal symbiosis promotes both growth and nutrient absorption in D. officinale, concurrently increasing polysaccharide content. Through transcriptome analysis, we identified 59 differentially expressed genes associated with polysaccharide metabolism, alongside key genes and transcription factors integral to the regulatory network. Notably, the glycosyltransferase gene DoUGT83A1 was found to negatively regulate the mycorrhizal symbiotic system when heterologously expressed in tomato. This study provides a fundamental theoretical basis for elucidating the molecular mechanisms underlying polysaccharide synthesis in D. officinale and offers new insights for optimizing cultivation practices to enhance medicinal quality.

To select and breed superior varieties of Dendrobium officinale with high quality and strong resistance to adverse conditions, a systematic selection process was employed to screen for outstanding strains, complemented by tissue culture for seed propagation. Following screening and self-purification, a new variety, ‘Tiefeng No.1’, was developed. Between 2019 and 2023, a comprehensive assessment of its characteristics, regional product ratio tests, and productivity research was meticulously conducted. The results indicated that the new variety of Dendrobium officinale is stable and of excellent quality. The polysaccharide content ranged from 44.35% to 58.55%, and the mannose content varied from 14.03% to 22.38%, both of which meet the standards set by the Chinese Pharmacopoeia (2020). The anthocyanidin content was measured at 94.76 to 115.43 μg/g, which is double that of the Yueqing landraces. It exhibits good frost resistance and disease resistance. Through production verification and demonstration, ‘Tiefeng No.1’ has proven to possess excellent quality and high yield, showcasing significant potential for promotion in the primary growing regions.