Hubei University of Technology

Lactobacillus plantarum is a widely recognized probiotic that forms biofilms to enhance environmental tolerance and probiotic properties, but the mechanisms regulating its biofilm formation remain unclear. This study successfully used CRISPR-Cas9 to delete the pfs gene in the high biofilm-producing strain L. plantarum R, and first investigated its role by integrated transcriptomic and metabolomic analyses. The pfs gene participates in the activated methyl cycle and AI-2 synthesis, which is involved in quorum sensing and biofilm formation. Deletion of pfs increased biofilm biomass by 91% and markedly enhanced matrix accumulation, including exopolysaccharides, extracellular proteins and extracellular DNA (eDNA). Transcriptomic analysis revealed significant perturbation of cysteine and methionine metabolism and altered expression of key genes involved in exopolysaccharide synthesis. Metabolomic profiling identified 223 differentially expressed metabolites, primarily associated with carbon flux and EPS precursor pathways. In summary, pfs deletion enhances biofilm formation via metabolic reprogramming rather than classical AI-2 dependent QS pathways. This study provides new insights into the pfs gene-mediated regulation of biofilm formation in L. plantarum and establishes a foundation for future strategies to manipulate biofilm formation in industrial applications.

The plant cell wall is a complex matrix critical for structural integrity, growth, and biomass utilization. This study investigates the distinct roles of cytosolic and chloroplastic UDP-glucose epimerases (CytoUGE and CpUGE) in regulating cell wall assembly and mechanical strength in Oryza sativa. By genetic modulation, we demonstrate that both CytoUGE and CpUGE enhance photosynthesis and increase the content of cellulose, hemicellulose, and lignin, thereby improving stem mechanical strength. Notably, CpUGE exerts a more pronounced effect on cellulose crystallinity while reducing xylan interference with cellulose microfibrils. Detailed monosaccharide analysis reveals that CpUGE promotes tighter xylan-lignin interactions and lower arabinose substitution in alkali-insoluble xylan, contributing to a more ordered cell wall architecture. Atomic force microscopy reveals that cellulose nanocrystals (CNCs) derived from CytoUGE exhibit a tendency to self-aggregate, forming structures of significantly larger dimensions. Moreover, modulation of both UGEs bidirectionally tunes CNC dimensions-overexpression enhances mechanical reinforcement, while loss-of-function reduces CNC size to increase reactivity. Integrate analyses identify the alkali-insoluble and soluble arabinose/xylose ratios as key indicators linking cell wall structure to mechanics. Our findings reveal that spatially separated UGE differentially regulate xylan interplay, providing a strategic target for engineering rice with improved cellulose quality for both agricultural and industrial applications.

This study elucidates the microstructural evolution of ethanol clusters and their regulatory role in flavor ester solubility during the aging of Soy sauce flavor Baijiu. Using integrated fluorescence and Raman spectroscopy, we show that Liquid-Liquid Phase Separation (LLPS) transforms ethanol clusters from hydrophilic to hydrophobic microdomains. Methodologically, we innovatively combined alcohol dehydrogenase (ADH) activity assay with Nile Red fluorescence probing to distinguish ethanol molecular states. Mass spectrometry further reveals a Non-Monotonic dissolution pattern for four key long-chain fatty acid ethyl esters: initial solubility increase through hydrophobic microdomains is later reversed by steric hindrance due to excessive cluster densification during extended aging. In samples aged over 30 years, pronounced ethanol cluster aggregation triggers flavor precipitation, evidenced by decreased free ethanol and solid deposit formation. These findings uncover the microstructural mechanism linking phase separation to flavor stability, offering a theoretical basis for improving Baijiu colloidal properties and sensory quality.