Molecular Insights into Fungal Innate Immunity Using the Neurospora crassa - Pseudomonas syringae Model

Area of Science:

• Fungal immunology
• Microbial interactions
• Comparative genomics

Background:

• Comparative genomics suggests fungi have immune systems akin to plants and animals.
• Limited evidence exists for fungal recognition and defense against other microbes.

Purpose of the Study:

• To investigate immediate fungal responses to bacterial interaction using a model system.
• To identify genes and pathways involved in the fungal immune response.

Main Methods:

• Utilized a model system of *Neurospora crassa* and *Pseudomonas syringae* DC3000.
• Performed transcriptomics on *N. crassa* germlings upon bacterial contact.
• Dissected mutant strains for key defense-related genes.

Main Results:

• Fungal germlings initiated transcriptional responses within 10 minutes, involving reactive oxygen species, trace metal metabolism, and cell wall remodeling.
• Mutants in genes for copper transport (tcu-1), ferric reductase (fer-1), superoxide reductase (sod-2), multidrug resistance (mdr-6), lysozyme (lyz), and Woronin body tethering (lah-1, lah-2) exhibited increased susceptibility to bacterial colonization.
• The Type III secretion system (T3SS) of *P. syringae* influenced bacterial colonization of *N. crassa*.

Conclusions:

• Established a bacterial-fungal model system in Dikarya to study fungal immunity.
• Identified seven genes critical for *N. crassa*'s defense against bacterial attack.
• Provided mechanistic insights into the putative fungal immune system's signaling pathways.