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Updated: Jun 12, 2026

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions
11:42

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions

Published on: September 30, 2016

Fungal dimorphism regulated gene expression in Ustilago maydis: II. Filament down-regulated genes

María D García-Pedrajas1, Scott E Gold

  • 1Department of Plant Pathology. University of Georgia, Athens, GA 30602-7274, USA.

Molecular Plant Pathology
|June 23, 2010
PubMed

Insights

Ustilago maydis switches between budding and filamentous forms, with filamentous growth essential for infecting corn. This study identified genes specifically down-regulated in the filamentous form, crucial for understanding Ustilago maydis pathogenicity.

Area of Science:

  • Mycology
  • Plant Pathology
  • Molecular Biology

Background:

  • Ustilago maydis exhibits dimorphic growth, switching between haploid budding and filamentous dikaryotic forms.
  • Filamentous growth is essential for Ustilago maydis pathogenicity in corn plants.
  • The cAMP signaling pathway influences dimorphism and pathogenicity, with gene repression in filamentous cells potentially key for virulence.

Purpose of the Study:

  • To identify genes specifically down-regulated in the filamentous growth form of Ustilago maydis.
  • To understand the role of wild-type budding cells in the life and disease cycle of U. maydis.
  • To identify potential targets for U. maydis virulence by analyzing differentially expressed genes.

Main Methods:

  • Suppression subtractive hybridization was employed to identify differentially expressed genes.
  • A cDNA library of approximately 5500 clones was screened using reverse Northern blot analysis.
  • Iterative sequencing and hybridization were used to identify unique differential genes, followed by Northern blot confirmation.

Main Results:

  • Over 88% of differentially expressed clones corresponded to 48 different genes.
  • Differential expression was confirmed for 37 genes, with 8 genes exclusively detected in budding cells.
  • Expression levels in budding cells varied from two-fold to 65-fold higher than in filamentous cells.
  • Twenty-seven of the 37 confirmed differential genes showed similarity to known database sequences across various functional categories.

Conclusions:

  • This study identified numerous genes down-regulated during filamentous growth in Ustilago maydis.
  • These identified genes are crucial for understanding the dimorphic switch and pathogenicity mechanisms.
  • Future research will involve creating deletion mutants to elucidate the roles of highly differentially expressed genes in morphogenesis and pathogenesis.

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