Fungal Innate Immunity Induced by Bacterial Microbe-Associated Molecular Patterns (MAMPs)
Simon Ipcho1, Thomas Sundelin1, Gitte Erbs1
1Department of Plant and Environmental Sciences (PLEN), University of Copenhagen, Denmark.
Abstract:
Plants and animals detect bacterial presence through Microbe-Associated Molecular Patterns (MAMPs) which induce an innate immune response. The field of fungal-bacterial interaction at the molecular level is still in its infancy and little is known about MAMPs and their detection by fungi. Exposing Fusarium graminearum to bacterial MAMPs led to increased fungal membrane hyperpolarization, a putative defense response, and a range of transcriptional responses. The fungus reacted with a different transcript profile to each of the three tested MAMPs, although a core set of genes related to energy generation, transport, amino acid production, secondary metabolism, and especially iron uptake were detected for all three. Half of the genes related to iron uptake were predicted MirA type transporters that potentially take up bacterial siderophores. These quick responses can be viewed as a preparation for further interactions with beneficial or pathogenic bacteria, and constitute a fungal innate immune response with similarities to those of plants and animals.
Insights
Fungi like Fusarium graminearum possess innate immunity, responding to bacterial Microbe-Associated Molecular Patterns (MAMPs) with gene expression changes, particularly for iron uptake, akin to plant and animal defenses.
Area of Science:
- Mycology
- Microbiology
- Plant Pathology
Background:
- Plants and animals use Microbe-Associated Molecular Patterns (MAMPs) to detect bacteria and trigger innate immunity.
- Fungal-bacterial interactions at the molecular level are not well understood, especially regarding MAMP perception by fungi.
Purpose of the Study:
- To investigate the molecular responses of the fungus Fusarium graminearum to bacterial MAMPs.
- To determine if fungi exhibit innate immune responses similar to plants and animals.
Main Methods:
- Fusarium graminearum was exposed to three different bacterial MAMPs.
- Fungal membrane potential and gene expression (transcriptional profiling) were analyzed.
Main Results:
- Exposure to MAMPs induced fungal membrane hyperpolarization, suggesting a defense mechanism.
- Each MAMP elicited a unique transcriptional profile in the fungus.
- A conserved set of genes, including those for energy, transport, amino acid synthesis, secondary metabolism, and iron uptake, were upregulated by all MAMPs.
- Iron uptake genes, particularly MirA-type transporters, were significantly upregulated, indicating potential uptake of bacterial siderophores.
Conclusions:
- Fusarium graminearum demonstrates an innate immune response to bacterial MAMPs.
- These responses, including enhanced iron uptake, prepare the fungus for interactions with bacteria.
- Fungal innate immunity shows similarities to that of plants and animals.
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