Development of a genetic tool for visualization of photosynthetic bacteria (PSB) is essential for understanding microbial function during their interaction with plant and microflora. In this study, Rhodopseudomonas palustris GJ-22-gfp harboring the vector pBBR1-pckA_PT-gfp was constructed using an electroporation transformation method and was used for dynamic tracing of bacteria in plants. The results showed that strain GJ-22-gfp was stable and did not affect the biocontrol function, and the Confocal Laser Scanning Microscopy (CLSM) results indicated it could successfully colonised on the surface of leaf and root of tobacco and rice. In tobacco leaves, cells formed aggregates on the mesophyll epidermal cells. While in rice, no aggregate was found. Instead, the fluorescent cells colonise the longitudinal intercellular spaces between epidermal cells. In addition, the results of strain GJ-22 on the growth promotion and disease resistance of tobacco and rice indicated that the different colonization patterns might be related to the bacteria could induce systemic resistance in tobacco.

Huangshui (HS) is a key byproduct of Chinese strong-flavor Baijiu (a traditional distilled spirit) fermentation. This study investigated microbial succession and flavor formation across five key fermentation stages using high-throughput sequencing, physicochemical analysis, and untargeted GC-MS. The results show that Lactobacillus dominated the bacterial communities, while Thermoascus, Aspergillus, and Candida were core fungal genera. Redundancy analysis (RDA) identified acidity, available phosphorus, and ammonia nitrogen as the primary physicochemical drivers of microbial succession. Untargeted metabolomics detected 300 volatile compounds, with 29 discriminant volatile metabolites (VIP > 1.0 or p < 0.05), mainly enriched in carbohydrate and amino acid metabolism pathways associated with Lactobacillus, Thermomyces, Wickerhamomyces, and Kazachstania. These findings establish a link among physicochemical properties, microbiota assembly, and flavor metabolism, providing potential targets for optimizing Baijiu fermentation quality.