The germination of fungal spores in water and enhanced their resistance to chlor(am)ine: Characteristics and mechanisms

Abstract

Waterborne fungal spores could aggregate and germinate to form biofilms, and current studies mainly focus on the control of dormant and aggregated spores. Herein, the characteristics of fungal spores during germination and the control of germinated spores were investigated. There was no significant difference between the germination percentages at the same carbon concentration (per spore) in the medium and surface water, suggesting the great germination potential of fungal spores in surface water. During germination, the cell size and the complication increased. Besides, the DNA content, esterase activity and intracellular ROS level of fungal spores also increased during germination. Accordingly, the germinated spores had more differential genes and metabolites to regulate germination. The k-Cl2 and the k-NH2Cl of Aspergillus niger spores with 5 %-45 % germination were 0.15–0.23 min−1 and 0.23–0.28 min−1, which were lower than that of dormant spores (0.062 and 0.063 min−1), suggesting that germinated spores were more resistant to chlor(am)ine than dormant spores. The k-Cl2 and k-NH2Cl of germinated spores with different germination percentages were highly negatively related to cell size and the esterase activities. The transcriptome and metabolome analysis showed that germinated spores reprogrammed the related germination genes and promoted chitosan biosynthesis in the cell wall and protein synthesis, thereby enhancing cellular resistance to chlor(am)ine.