As leaf-harvest plants, tea trees show unique nutrient requirements, different from those of corn and other field crops. However, the effects of nitrogen (N), phosphorus (P), and potassium (K) application on the accumulation of quality-related compounds and the mechanisms underlying how nutrients affect tea-leaf metabolism have not been well elucidated. Here, fertilizers with different N, P, K ratios were applied to tea plants in pot experiments, and metabolomics based on gas chromatography-mass spectrometry (GC-MS) combined with multivariate statistical and quantitative detections were conducted to assess the responses of quality-related compounds to NPK in tea leaves. An increased proportion of P and K was beneficial for the accumulation of carbohydrates and catechins in shoots, although the total carbon content did not increase significantly. In contrast, a high proportion of P and K input reduced the relative chlorophyll content in shoots, and the contents of free amino acids such as theanine and glutamic acid negatively correlated with P and K nutrient content. Moreover, the metabolism of malic acid in the tricarboxylic acid cycle was highly promoted by increasing the application of P and K. These results validate our suggestion that the application of high amounts of P and K in tea plantations induces the biased reallocation of photosynthates and carbohydrates to the catechin pathway by promoting malic acid metabolism in young tea shoots, which further affects tea quality. The results of this study provide theoretical ground for tea quality improvement by optimizing fertilization strategies.

Background: Leaves of the medicinal plantAmpelopsis grossedentata, which is commonly known as vine tea, are used widely in the traditional Chinese beverage in southwest China. The leaves contain a large amount of dihydromyricetin, a compound with various biological activities. However, the transcript profiles involved in its biosynthetic pathway in this plant are unknown.Results: We conducted a transcriptome analysis of both young and old leaves of the vine tea plant using Illumina sequencing. Of the transcriptome datasets, a total of 52.47 million and 47.25 million clean reads were obtained from young and old leaves, respectively. Among 471,658 transcripts and 177,422 genes generated, 7768 differentially expressed genes were identified in leaves at these two stages of development. The phenylpropanoid biosynthetic pathway of vine tea was investigated according to the transcriptome profiling analysis. Most of the genes encoding phenylpropanoid biosynthesis enzymes were identified and found to be differentially expressed in different tissues and leaf stages of vine tea and also greatly contributed to the biosynthesis of dihydromyricetin in vine tea.Conclusions: To the best of our knowledge, this is the first formal study to explore the transcriptome ofA. grossedentata.The study provides an insight into the expression patterns and differential distribution of genes related to dihydromyricetin biosynthesis in vine tea. The information may pave the way to metabolically engineering plants with higher flavonoid content.

The inherent barriers posed by bacterial outer membranes, efflux pumps, and biofilm matrices significantly limit the clinical efficacy of antimicrobial agents, underscoring the urgent need for strategies to enhance drug penetration. Integrating pathogen-specific exogenous nutrients with conventional antibiotics has emerged as a promising approach, facilitating the targeted delivery and enhanced efficacy of antimicrobial compounds. In this study, we aimed to improve antimicrobial efficacy by enhancing transmembrane transport. First, we comprehensively compared various genome-scale metabolic reconstruction methods to identify the optimal approach. Subsequently, we enhanced our previous approach to identify exogenous nutrients by integrating topological screening, flux scoring, and chemical structure analysis. Key exogenous nutrients were identified for three pathogens: urea for Acinetobacter baumannii , acetamide for Pseudomonas aeruginosa , and succinic acid for Salmonella enterica . Growth assays confirmed that these nutrients significantly promoted bacterial proliferation. Leveraging these findings, four novel antimicrobial compounds (NC, NA, MA, and MN) were synthesized by conjugating membrane-resistant nalidixic acid or magnolol with the respective nutrients. MN enhanced the antimicrobial activity against wild-type S. enterica by 56.5%, while MA and NA boosted the activity against wild-type P. aeruginosa by 51.4% and 70.4%, respectively. Moreover, NC improved efficacy against drug-resistant A. baumannii by fourfold. These results demonstrate that conjugating exogenous nutrients with antibiotics can effectively enhance antimicrobial activity and help overcome membrane-associated resistance. This nutrient-conjugation strategy offers a promising avenue for developing new antimicrobial agents. IMPORTANCE: The difficulty of achieving effective drug penetration into bacterial cells is a major obstacle limiting antimicrobial efficacy and posing a significant global health challenge. This study demonstrates a novel strategy to combat resistance by “hijacking” nutrients that pathogens rely on for growth. By combining antibiotics with these nutrients, drugs can bypass membrane barriers and effectively reach their targets. The preferred exogenous nutrients of the high-priority pathogens Acinetobacter baumannii , Pseudomonas aeruginosa , and Salmonella enterica were identified. Combining these with the existing antibiotics markedly enhanced antimicrobial efficacy against both susceptible and resistant strains. This approach offers a practical way to revitalize existing antibiotics and design new ones, potentially slowing the spread of resistance. Importantly, it highlights how understanding bacterial metabolism can lead to smarter drug design, addressing a critical need in global health.