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Pheromones trigger filamentous growth in Ustilago maydis
T Spellig1, M Bölker, F Lottspeich
1Institut für Genetik und Mikrobiologie der Universität München, Germany.
The EMBO Journal
|April 1, 1994
Summary
Pheromones from the smut fungus Ustilago maydis trigger mating and a switch to filamentous growth. These secreted peptides, a1 and a2, are crucial for cell recognition and initiating pathogenic development.
Area of Science:
- Fungal biology
- Molecular genetics
- Cell signaling
Background:
- Cell recognition and mating in Ustilago maydis are thought to involve specific pheromones and receptors.
- The genes for these pheromones are located in the a mating type locus, with alleles a1 and a2.
Purpose of the Study:
- To identify and characterize the pheromones involved in Ustilago maydis mating.
- To investigate the role of pheromones in inducing morphological changes and initiating pathogenic development.
Main Methods:
- Utilizing a biological assay based on pheromone-induced morphological switching (yeast-like to filamentous growth).
- Purification and structural determination of a1 and a2 pheromones.
- Analysis of post-translational modifications (farnesylation, carboxyl methyl esterification) and their impact on activity.
Main Results:
- Successfully purified a1 and a2 pheromones, revealing structures of 13 and 9 amino acids, respectively.
- Both pheromones undergo farnesylation and carboxyl methyl esterification of the C-terminal cysteine.
- Unmodified a1 peptide showed significantly reduced activity.
- Pheromones induced conjugation tubes and mating competence in opposite mating types, and fusion in same mating types.
Conclusions:
- Pheromones are key signaling molecules in Ustilago maydis, mediating cell recognition and mating.
- Pheromone binding induces a switch to filamentous growth, a critical step in pathogenic development.
- Post-translational modifications are essential for full pheromone activity.