This study employed wild sea buckthorn (Hippophae rhamnoides L.) fruits harvested in Qinghai Province as experimental material. Following compositional analysis of their flavonoids, the antibacterial efficacy and mechanistic pathways of flavonoids in sea buckthorn against Helicobacter pylori (H. pylori) were systematically examined through in vitro and animal model experiments. The results showed that the main flavonoids in sea buckthorn were rutin, quercetin-3-O-glucoside, quercetin, catechin, isorhamnetin, kaempferol-3-O-glucoside, kaempferol and epicatechin. Among them, quercetin, isorhamnetin and kaempferol had strong inhibitory activity against H. pylori. In vitro, sea buckthorn flavonoids inhibited the growth of H. pylori through multiple mechanisms: inducing morphological transformation from rod-shaped to spherical bacteria, promoting cell shrinkage and rupture, disrupting the cell membrane to cause leakage of intracellular macromolecules, increasing membrane permeability, and suppressing urease activity. Sea buckthorn flavonoids exert therapeutic effects on H. pylori-infected mice through multiple mechanisms, including the alleviation of gastric mucosal inflammation via the Nuclear Factor KappaB (NF-κB) signaling pathway, the down-regulation of gastrin-17 (GAS17) to suppress gastric acid production, and the up-regulation of epidermal growth factor (EGF) expression to promote gastric mucosal repair and modulate the composition of gastric microbiota. This study systematically elucidated the anti-H. pylori activity and antibacterial mechanisms of flavonoids derived from sea buckthorn fruits, providing a theoretical basis for the screening of natural antibacterial agents from this plant source.

1-deoxy-D-xylulose-5-phosphate synthase (DXS) is the first key enzyme in the methylerythritol phosphate (MEP) pathway of plant terpenoid biosynthesis, and it plays a vital role in Eucommia ulmoides terpenoid biosynthesis. In this study, bioinformatics methods were used to comprehensively identify and analyze the expression pattern of the EuDXS gene family, aiming to provide a basis for further functional study of EuDXS genes. A total of four EuDXS gene family members were identified and named EuDXS1 to EuDXS4. The encoded proteins contained 625 to 713 amino acid residues, with molecular weight ranging from 67.98 kDa to 76.61 kDa. The theoretical isoelectric points varied from 6.79 to 8.69, aliphatic index was between 85.29 and 91.29. In silico subcellular localization prediction revealed that all EuDXS proteins were localized in chloroplasts. EuDXS gene members were categorized into three subfamilies, which were unevenly distributed on three chromosomes. The promoters of EuDXS genes contained various cis-acting elements related to stress response, phytohormone signaling, light response and growth regulation. Expression pattern analysis showed that EuDXS genes exhibited tissue-specific expression: EuDXS1 was highly expressed in stem, leaf and fruit, EuDXS2 was predominantly expressed in fruit. EuDXS1 and EuDXS2 exhibited high expression levels at the early developmental stage of fruits and leaves. In addition, EuDXS genes responded to salt and drought stress in varying degrees. Transient expression in tobacco revealed that EuDXS1 and EuDXS2 could increase carotenoid and total chlorophyll content. This study will provide important genetic resources for further exploration of EuDXS gene function and germplasm innovation in E. ulmoides.

Soil multifunctionality (SMF) is a core indicator of plantation soil ecological function, and microbial diversity plays a vital role in sustaining it. However, cross-site rhizosphere and bulk SMF disparities and their microbial driving mechanisms remain unclear in Eucommia ulmoides plantations. Here, we collected rhizosphere and bulk soils from three typical sites (Mengzhou, MZ; Liangyuan, LY; and Yuanyang, YY). Soil chemical properties, extracellular enzymes, microbial alpha diversity, community composition and cross-kingdom network topology were measured. Correlation heatmaps, random forest, Redundancy analysis (RDA) and Partial least path modeling (PLS-PM) were adopted to quantify SMF predictors and regulatory pathways. Rhizosphere soils possessed significantly higher alkaline hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK) than bulk soils at all sites. LY rhizosphere showed the greatest soil organic carbon (SOC), total potassium (TK), available nutrients and enzyme activities, while YY had higher total nitrogen (TN) and AP, yet the lowest enzyme levels. Rhizosphere bacterial and fungal alpha diversity was consistently higher across locations. SMF varied distinctly by site and compartment: LY had substantially higher SMF than MZ and YY in both rhizosphere and bulk soils, with rhizosphere SMF being consistently greater than bulk values across all sites. The PLS-PM (GOF = 0.70) indicated that soil chemical properties regulated SMF via dual pathways: they directly promoted microbial co-occurrence networks and indirectly modified network structure by altering fungal diversity, while suppressing bacterial diversity. Total effect analysis identified soil chemical properties and microbial co-occurrence networks as the core drivers of SMF variation. This work clarifies that rhizosphere effects and soil chemical properties jointly drive SMF by regulating microbial diversity and co-occurrence networks, offering theoretical guidance for sustainable soil management in E. ulmoides plantations.