Antagonistic and antibacterial activities of Talaromyces marneffei SA2a and its purpuride pigment against plant and human pathogens

Abstract

Abstract Background This study explores the biological potential of Talaromyces marneffei , a temperature-dependent dimorphic fungus that produces secondary metabolites with applications across environmental protection, agriculture, cosmetics, food, and medicine. Recognizing the growing need for biocontrol agents and effective antimicrobial agents, the study investigates the antagonistic and antimicrobial activities of Talaromyces marneffei and its red pigment against Macrophomina phaseolina and pathogenic bacteria. Methods Talaromyces marneffei was obtained from a microbial stock culture and revived on Potato Dextrose Agar. Antagonistic activity of the fungus was evaluated against Macrophomina phaseolina , which causes cassava tuber rot, using co-culture methods. The fungus was optimized for red pigment production, and the pigment was identified using a UV-visible spectrophotometer. Antimicrobial activity of the pigment was determined on multidrug-resistant clinical bacterial isolates using agar well diffusion method. Results The fungus demonstrated antagonistic activity against Macrophomina phaseolina , with a zone of inhibition surrounding its growth. The pigment was tentatively identified as Purpuride, with λmax at 512 nm. The optimum growth conditions, pH 5.4, 25 °C, and 4% glycerol, yielded maximum pigment. The pigment demonstrated inhibitory activities against Bacillus cereus ATCC 10876 (32 ± 0.50), Klebsiella pneumonia ATCC 8309 (24 ± 0.70), and Escherichia coli DSM 10974 (12 ± 1.41) mm. Conclusion This study demonstrated that Talaromyces marneffei and its red pigment exhibited significant antagonistic activity against Macrophomina phaseolina and inhibitory effects on multidrug-resistant bacteria. This study suggests that the fungus has biocontrol potential, and the red pigment could be used to address the global challenge of antibiotic resistance.