Many dyes and pigments are used in textile and printing industries, and their wastewater has been classed as a top source of pollution. Biodegradation of dyes by fungal laccase has great potential. In this work, the influence of reaction time, pH, temperature, dye concentration, metal ions, and mediators on laccase-catalyzed Remazol Brilliant Blue R dye (RBBR) decolorization were investigated in vitro using crude laccase from the white-rot fungus Ganoderma lucidum. The optimal decolorization percentage (50.3%) was achieved at 35 °C, pH 4.0, and 200 ppm RBBR in 30 min. The mediator effects from syringaldehyde, 1-hydroxybenzotriazole, and vanillin were compared, and 0.1 mM vanillin was found to obviously increase the decolorization percentage of RBBR to 98.7%. Laccase-mediated decolorization percentages significantly increased in the presence of 5 mM Na⁺ and Cu²⁺, and decolorization percentages reached 62.4% and 62.2%, respectively. Real-time fluorescence-quantitative PCR (RT-PCR) and protein mass spectrometry results showed that among the 15 laccase isoenzyme genes, Glac1 was the main laccase-contributing gene, contributing the most to the laccase enzyme activity and decolorization process. These results also indicate that under optimal conditions, G. lucidum laccases, especially Glac1, have a strong potential to remove RBBR from reactive dye effluent.

Leaf spot disease has recently emerged on Euonymus fortunei in Shanxi Province, China, causing noticeable foliar lesions and reducing ornamental value. The causal agent was identified as Alternaria alternata based on morphological characteristics and multilocus phylogenetic analysis using five loci (Alt a1, gapdh, RPB2, ITS, and OPA10-2). Biological characterization showed that mycelial growth was optimal at 27 ℃ on oatmeal agar, whereas conidial germination was favored under alkaline conditions (pH 9.0). The pathogen was sensitive to NaCl stress but showed no significant response to different light regimes. In vitro fungicide sensitivity assays revealed marked differences in inhibitory efficacy between mycelial growth and conidial germination, indicating strong developmental stage-dependent responses. Certain fungicide mixtures exhibited enhanced inhibitory effects compared with single compounds, suggesting potential synergistic interactions. Microscopic observations further revealed fungicide-induced morphological abnormalities, including hyphae swelling, roughened surfaces, reduced sporulation, and deformation of conidial germ tubes. This study represents the first report of A. alternata causing leaf spot disease on E. fortunei in China and provides a basis for understanding pathogen biology and developing effective chemical management strategies for this emerging ornamental disease.