SPP Project: Mechanisms of Basidiomycete Yeast Function in Complex Leaf Microbial Communities
This collaborative project, led by the Kemen and Doehlemann labs, investigates the role of basidiomycete yeasts in shaping microbial communities on Arabidopsis thaliana leaves. By focusing on yeasts and their interactions with the pathogen Albugo laibachii, this research aims to uncover mechanisms by which specific microbial interactions promote community stability and pathogen suppression, ultimately contributing to plant resilience.
Project Goals
The project centers on three main objectives:
- Identify Key Yeasts and Pathogen Interactions in Leaf Microbial Communities
Characterize basidiomycete yeasts that interact with A. laibachii and explore how these interactions influence microbial community structure. - Uncover Mechanistic Insights of Microbial Antagonism
Focus on specific enzymes, such as the GH25 lysozyme from Moesziomyces bullatus, to understand their roles in suppressing pathogens within microbial communities. - Develop Potential Biocontrol Strategies Using Natural Microbial Interactions
Investigate microbial interactions that could inspire biocontrol approaches to naturally reduce pathogen load in plant ecosystems.
Research Focus
1. Cross-Kingdom Interactions and Microbial Community Influence
This area explores how interactions between fungi, bacteria, and other microbes contribute to community structure and resilience.
- Recent Findings: We identified Albugo laibachii as a central "hub" organism that significantly influences microbial diversity in the Arabidopsis phyllosphere. Our studies show that basidiomycete yeasts, particularly Moesziomyces bullatus (MbA) and Cystofilobasidium species, play a crucial role in reducing A. laibachii infection, thereby protecting plants from pathogen colonization. Cystofilobasidium works synergistically with bacteria such as Pseudomonas extremaustralis, enhancing antimicrobial effects against pathogen-associated microbes. This targeted suppression highlights M. bullatus and Cystofilobasidium as key members of the health-associated microbial community in A. thaliana. Together, these findings underscore the diverse roles of basidiomycete yeasts within microbial networks, where they interact with other microbes to influence pathogen dynamics and contribute to plant health (Agler et al., PLOS Biology, 2016; Eitzen et al., eLife, 2021; Mahmoudi et al., bioRxiv, 2024).
2. Mechanistic Insights into Antagonistic Interactions
Here, we focus on identifying and characterizing enzymes and metabolites that play key roles in microbial antagonism.
- Recent Findings: Our collaborative study demonstrated that the GH25 lysozyme from M. bullatus significantly inhibits A. laibachii, reducing its ability to infect Arabidopsis leaves. This lysozyme cleaves peptidoglycan mainly in bacterial cell walls, acting as an effective biological deterrent. If this function is relevant for attacking the Albugo cell wall or if this is an indirect effect is currently unknown. Further analysis of Cystofilobasidium species revealed a unique antimicrobial activity when paired with certain bacterial strains, suggesting that cross-kingdom interactions contribute to pathogen suppression. Bioactive compounds isolated from these interactions are currently being characterized for their specific roles in microbial defense (Eitzen et al., eLife, 2021; Quinzer, Braun, et al. in preparation).
3. Advancing Biocontrol Strategies Using Microbial Interactions
This area aims to explore the application of microbial interactions in developing natural plant protection strategies.
- Recent Findings: The combined inhibitory effect of Cystofilobasidium yeasts and Pseudomonas extremaustralis against A. laibachii demonstrates a novel biocontrol method, harnessing naturally occurring microbial interactions. This approach emphasizes the potential of using native microbial communities to enhance plant resilience against pathogens, potentially reducing the need for chemical treatments in agricultural settings (Quinzer, Braun, et al. in preparation).
Innovative Approach
Our project combines experimental and computational approaches to map interactions within the Arabidopsis leaf microbiome. By focusing on cross-kingdom microbial interactions and characterizing specific antimicrobial enzymes and compounds, we aim to establish a foundation for microbial-based biocontrol strategies that enhance plant health naturally and sustainably.
Significance and Future Impact
This research advances our understanding of plant-microbe interactions and the role of basidiomycete yeasts in plant protection. By leveraging natural microbial antagonism, this project provides insights into developing sustainable plant protection methods, benefiting both agriculture and ecosystem management.