Genetic control of conventional and pheromone-stimulated biofilm formation in Candida albicans

PLoS Pathog. 2013;9(4):e1003305. doi: 10.1371/journal.ppat.1003305. Epub 2013 Apr 18.

Abstract

Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 196 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biofilms / growth & development*
  • Candida albicans / genetics
  • Candida albicans / growth & development
  • Candida albicans / physiology*
  • DNA-Binding Proteins / metabolism
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism*
  • Gene Expression
  • Gene Expression Regulation, Fungal
  • Phenotype
  • Pheromones / physiology
  • Signal Transduction
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*

Substances

  • CPH1 protein, Candida albicans
  • DNA-Binding Proteins
  • EFG1 protein, Candida albicans
  • Fungal Proteins
  • Ndt80 protein, Candida albicans
  • Pheromones
  • TEC1 protein, Candida albicans
  • Transcription Factors

Associated data

  • GEO/GSE44449