Secondary Metabolites Produced during Aspergillus fumigatus and Pseudomonas aeruginosa Biofilm Formation

Author(s)

Bastos, Rafael Wesley ; Akiyama, Daniel ; dos Reis, Thaila Fernanda ; Colabardini, Ana Cristina ; Luperini, Rafael Sanchez ; de Castro, Patricia Alves ; Baldini, Regina Lucia ; Fill, Taicia ; Goldman, Gustavo H.

• Document type: Journal article
• Source: MBIO; v. 13, n. 4, p. 17-pg., 2022-07-20.

Abstract

The interaction between Pseudomonas aeruginosa and Aspergillus fumigatus has been well characterized in vitro. In this scenario, the bacterium exerts a strong inhibitory effect against the fungus. In cystic fibrosis (CF), mucus plaques are formed in the patient's lungs, creating a hypoxic condition and a propitious environment for colonization and persistence of many microorganisms. There is clinical evidence showing that Aspergillus fumigatus can cocolonize CF patients with Pseudomonas aeruginosa, which has been associated with lung function decline. P. aeruginosa produces several compounds with inhibitory and antibiofilm effects against A. fumigatus in vitro; however, little is known about the fungal compounds produced in counterattack. Here, we annotated fungal and bacterial secondary metabolites (SM) produced in mixed biofilms under normoxia and hypoxia conditions. We detected nine SM produced by P. aeruginosa. Phenazines and different analogs of pyoverdin were the main compounds produced by P. aeruginosa, and their secretion levels were increased by the fungal presence. The roles of the two operons responsible for phenazine production (phzA1 and phzA2) were also investigated, and mutants lacking one of those operons were able to produce partial sets of phenazines. We detected a total of 20 SM secreted by A. fumigatus either in monoculture or in coculture with P. aeruginosa. All these compounds were secreted during biofilm formation in either normoxia or hypoxia. However, only eight compounds (demethoxyfumitremorgin C, fumitremorgin, ferrichrome, ferricrocin, triacetylfusigen, gliotoxin, gliotoxin E, and pyripyropene A) were detected during biofilm formation by the coculture of A. fumigatus and P. aeruginosa under normoxia and hypoxia conditions. Overall, we showed how diverse SM secretion is during A. fumigatus and P. aeruginosa mixed culture and how this can affect biofilm formation in normoxia and hypoxia. IMPORTANCE The interaction between Pseudomonas aeruginosa and Aspergillus fumigatus has been well characterized in vitro. In this scenario, the bacterium exerts a strong inhibitory effect against the fungus. However, little is known about the metabolites produced by the fungus to counterattack the bacteria. Our work aimed to annotate secondary metabolites (SM) secreted during coculture between P. aeruginosa and A. fumigatus during biofilm formation in both normoxia and hypoxia. The bacterium produces several different types of phenazines and pyoverdins in response to presence of the fungus. In contrast, we were able to annotate 29 metabolites produced during A. fumigatus biofilm formation, but only 8 compounds were detected during biofilm formation by the coculture of A. fumigatus and P. aeruginosa upon either normoxia or hypoxia. In conclusion, we detected many SM secreted during A. fumigatus and P. aeruginosa biofilm formation. This analysis provides several opportunities to understand the interactions between these two species. (AU)

• FAPESP's process: 17/07536-4 - Molecular Mechanisms Involved in Paradoxal Growth Induced by Caspofungin in Aspergillus fumigatus
• Grantee: Ana Cristina Colabardini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/07038-0 - Chemical and molecular investigation of natural products involved in Penicillium brasilianum-hosts interactions
• Grantee: Daniel Yuri Akiyama
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 21/11062-3 - Novel molecular mechanisms putatively involved with bacterial resistance to antibiotics
• Grantee: Regina Lúcia Baldini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/19821-5 - Molecular, phenotypic and immune response characterization of clinical isolates of Aspergillus nidulans
• Grantee: Rafael Wesley Bastos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/07870-9 - The influence of mitogen activated protein kinases (MAPK) on the expression of genetic determinants important for Aspergillus fumigatus virulence
• Grantee: Gustavo Henrique Goldman
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 21/00728-0 - A chemical approach to understand the Huanglongbing (greening) disease
• Grantee: Taicia Pacheco Fill
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/12948-7 - The role of mitogen-activated protein kinase (MPKA) MpkA in regulating gliotoxin production in Aspergillus fumigatus.
• Grantee: Patrícia Alves de Castro Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral