Transcription Activator-Like Effectors from Endosymbiotic Bacteria Control the Reproduction of Their Fungal Host
- Author: mycolabadmin
- 2023-11-16
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Summary
This research reveals how certain bacteria living inside fungi can control their host’s ability to reproduce. The bacteria use specialized proteins called TAL effectors to influence fungal spore production, which is essential for maintaining their symbiotic relationship. This discovery helps us understand how microorganisms work together in nature and could lead to new ways to control crop diseases.
Impacts on everyday life:
– Provides insights that could help protect rice crops from fungal diseases
– Advances our understanding of beneficial microbe relationships in agriculture
– Could lead to new strategies for controlling harmful plant pathogens
– May inspire new approaches for managing microbial interactions in medicine and biotechnology
– Demonstrates how studying microscopic interactions can solve real-world problems
Background
The phytopathogenic fungus Rhizopus microsporus harbors bacterial endosymbionts (Mycetohabitans rhizoxinica) that produce virulence factors causing rice seedling blight. The persistence of this symbiotic relationship depends on the bacteria evading fungal defenses and controlling fungal reproduction through a Type 3 secretion system (T3SS). However, the specific effectors secreted through T3SS and their effects on fungal physiology have remained unclear.
Objective
To identify and characterize the T3SS effectors involved in controlling fungal reproduction and maintaining the symbiotic relationship between M. rhizoxinica and R. microsporus.
Results
The study identified genes encoding an AWR peptide and multiple transcription activator-like (TAL) effectors across Mycetohabitans strains. While AWR-deficient bacteria maintained normal symbiotic function, strains lacking individual MTALs (MTAL1, MTAL2, MTAL3) showed significantly reduced ability to induce fungal sporulation. The MTAL-deficient bacteria could still colonize fungal hyphae but failed to properly control host reproduction. Trans-complementation experiments confirmed that MTALs are essential for normal fungal sporulation.
Conclusion
The study demonstrates that bacterial TAL effectors (MTALs) are crucial for controlling fungal host reproduction in the Rhizopus-Mycetohabitans symbiosis. This represents a novel case of bacterial effectors controlling host reproduction and provides insights into how prokaryotic symbionts interact with their eukaryotic hosts.
- Published in:mBio,
- Study Type:Laboratory Research,
- Source: 10.1128/mbio.01824-23