Wuyistar (China)

Citrus huanglongbing (HLB), caused by 'Candidatus Liberibacter asiaticus' (CLas), is a destructive disease threatening global citrus industry. Although citrus cultivars differ in HLB sensitivity, how infection alters endophytic bacterial communities in cultivars with contrasting susceptibility remains unclear. Here, we compared endophytic microbiome shifts in leaf and root tissues of HLB-susceptible Shatangju mandarin (Citrus reticulata cv. Shatangju) and HLB-tolerant Shatian pomelo (C. maxima cv. Shatian) at 10 months postgrafting with CLas-infected buds. Infected Shatangju mandarin showed severe symptoms and higher CLas levels in leaves than in roots, while infected Shatian pomelo remained asymptomatic with higher CLas in roots than in leaves. High-throughput 16S rRNA gene sequencing revealed that CLas infection restructured the endophytic microbial community in a tissue-specific manner. CLas-infected Shatian pomelo leaves displayed increased microbial diversity and network complexity, while CLas-infected Shatangju mandarin roots harbored more disease-suppressive taxa like Streptomyces. Across both cultivars, network complexity correlated inversely with CLas abundance. Key genera (e.g., Pseudomonas, Streptomyces, and Prevotella) correlated positively with CLas, suggesting roles in mitigating pathogen effects. Predicted functional profiling indicated activated pathways (amino acid metabolism, terpenoid/polyketide biosynthesis, and xenobiotic biodegradation) potentially supporting host defense in infected tissues. The HLB tolerance of Shatian pomelo appeared linked to tissue-specific bacterial restructuring, particularly recruitment of antibiotic-producing bacteria and enhanced metabolic resilience. These findings elucidated cultivar-specific microbial strategies against CLas, offering insights for microbiome-mediated HLB management.

This study established a chromatographic fingerprint analysis method for aged rock tea using ultra‐high performance liquid chromatography–mass spectrometry (UPLC–MS) technology to profile its chemical components. The chromatographic separation showed excellent performance, with more than 30 chemical components of common peaks identified. Comparative analysis of fingerprint profiles from different vintage‐aged teas revealed significant differences in similarity, allowing classification into three distinct categories based on similarity indices. This method facilitates the classification of aged teas and quality evaluation of traditional Chinese medicinal materials. Component analysis of aged tea demonstrated that tea extracts are rich in flavonoid compounds, both in content and diversity, serving as a primary dietary source of total flavonoids. In subsequent animal experiments, functional flavonoids derived from aged tea extracts exhibited positive regulatory effects against multiple free radicals, including ·OH, H2O2, DPPH−, and ABTS, in vitro. In vivo studies showed that these flavonoids reduced malondialdehyde (MDA) levels in the cerebral cortex of Alzheimer’s disease (AD) mice, enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), mitigated oxidative damage, and improved cognitive dysfunction in AD mice. This research provides crucial references for future studies on traditional Chinese medicines aimed at ameliorating cognitive dysfunction.

ABSTRACTThe mitochondrial genome (mitogenome) plays a critical role in energy production and is frequently subject to positive selection due to its impact on adaptive evolution. In this study, we investigated positive selection pressures in the mitogenomes of Dopasia (Anguidae), a genus that occupies diverse habitats. Using next‐generation sequencing, we determined the complete mitogenomes of eight individuals (six D. gracilis and two D. harti) and compared them with 28 published mitogenomes of the Anguidae family from GenBank. Although purifying selection is the predominant evolutionary force, six of the 13 protein‐coding genes showed signatures of positive selection. Notably, amino acid preferences at these sites correlated with the geographic distributions of the species, suggesting the involvement of the mitogenome in environmental adaptation. We also mapped these sites onto three‐dimensional protein structures and transmembrane domains. Phylogenetic analyses resolved Dopasia's relationship with other Anguidae species, but challenged the monophyly of D. hainanensis within the genus. Our findings highlight the potential role of the mitogenome in ecological adaptation and underscore the need for a broader sampling of Anguidae mitogenomes to clarify evolutionary mechanisms.

Wuyi rock tea is renowned for its distinctive ″rock flavor,″ largely formed during the turning stage through mechanical stress and enzymatic changes.To investigate its molecular basis, we assembled the most contiguous tea genome to date from the representative cultivar "Rougui" and identified structural variations distributed across flavor-related genes and pathways. Metabolomic profiling highlighted the fourth and fifth turning stages as critical, showing surges in volatiles and nucleotides, rapid catechin and amino acid degradation, and a striking 180-fold rise in theaflavins. Leveraging transcriptome data with >97% mapping rate to the "Rougui" genome, we identified 1248 genes forming key coexpression modules associated with volatiles and theaflavins biosynthesis. These modules include 10 TPSs, PPO, POD, and multiple upstream structural genes that were coordinately activated during the sequential turning stages. The results offer genomic resources and insights into the regulation of flavor formation in Wuyi rock tea.

Soil microorganisms are crucial in terrestrial ecosystems, influencing carbon (C) sequestration, yet their metabolic activities are often constrained by nitrogen (N) and phosphorus (P) availability. Despite this, a global understanding of microbial nutrient limitation remains elusive. We synthesised 1245 observations from 225 articles to elucidate patterns and factors of microbial nutrient limitation. Contrary to convention, soil microbial P limitation is widespread (83.78% of observations), with N limitation mainly in temperate zones and pronounced P limitation in tropical and cold zones. Soil microbial P limitation correlates positively with mean annual precipitation and clay content, while N limitation correlates negatively with soil pH. Importantly, microbial nutrient limitation directly affects C cycling, as microbial C limitation increases with decreasing N or P limitation. This underscores the significance of microbial nutrient limitation in terrestrial C cycling and the need to incorporate it into Earth system models for accurate predictions under changing conditions.

Aroma extract dilution analysis was performed on volatile fractions extracted from a freshly prepared Dahongpao (DHP) tea infusion using solvent-assisted flavor evaporation, yielding 65 odor-active domains with flavor dilution factors ranging between 32 and 32,768. In addition, six aromatic substances were captured by headspace analysis. Quantitation of 54 compounds by an internal standard method and stable isotope dilution assays revealed that the concentrations of 32 odorants exceeded their respective orthonasal odor threshold values in tea infusion. The results of odor activity values (OAVs) suggested that 2-metylbutanal (malty) and γ-hexalactone (coconut-like) had the highest OAVs (248 and 154). Eight odorants including γ-hexalactone (OAV 154), methyl 2-methylbutanoate (59), phenylacetic acid (7.2), acetylpyrazine (5.7), 2-methoxyphenol (3.4), p-cresol (2.7), 2,6-diethylpyrazine (2.7), and vanillin (1.8) were newly identified as key odorants in DHP tea infusion. An aroma recombination model in a non-volatile matrix extracted from tea infusion satisfactorily mimicked the overall aroma of DHP tea infusion, thereby confirming the identification and quantitative experiments. Omission experiments verified the obvious significance of 6-methyl-5-hepten-2-one (OAV 91), 2-ethyl-3,5-dimethylpyrazine (19), 4-hydroxy-2,5-dimethylfuran-3(2H)-one (13), and acetylpyrazine (5.7) as key odorants for the special roasty and caramel-like aroma of DHP tea.