Modulation of transcription factors by Clp1 specifies mating-type dependent signaling during biotrophic development of Ustilago maydis
Ustilago maydis is a dimorphic Basidiomycete and pathogen of corn. Prerequisite for a successful infection process is the switch from yeast-like budding to filamentous growth. This dimorphic transition is accompanied by a G2 cell cycle arrest, and ultimately controlled by the heterodimeric homeodomain transcription factor bE/bW encoded by the b-mating type locus. We could show that the majority of the bE/bW dependently expressed genes are regulated via Rbf1, a bE/bW dependently regulated transcription factor. Rbf1 is required and sufficient for filament formation and G2 cell cycle arrest. The bE/bW and Rbf1 induced cell cycle arrest is released via physical interaction of both transcription factors with Clp1. clp1 is a directly b-regulated gene and required for biotrophic development. Simultaneous induction of bE/bW and Clp1 blocks the b-induced dimorphic switch, and array analysis revealed the complete blocking of b-dependent transcriptional regulation. Interestingly, simultaneous expression of Clp1 and Rbf1 leads to specific downregulation of the U. maydis pheromone pathway. We hypothesize that the interaction of Clp1 with Rbf1 and bE/bW orchestrates pheromone and b-dependent signalling pathways to coordinate mating, the dimorphic transition and cell cycle to facilitate in planta development of U. maydis.
Heimel K, Scherer M, Schuler D, Kämper J. (2010) The Ustilago maydis Clp1 Protein Orchestrates Pheromone and b-Dependent Signaling Pathways to Coordinate the Cell Cycle and Pathogenic Development. Plant Cell. 2010 Aug;22(8):2908-22. Epub 2010 Aug 20.
Heimel, K.*, Scherer, M.*,Vranes, M., Wahl, R., Pothiratana, C., Schuler, D., Vincon, V., Finkernagel, F., Flor-Parra, I. and Kämper, J. (2010) The transcription factor Rbf1 is the master regulator for b-mating type controlled pathogenic development in Ustilago maydis. in revision. *authors contributed equally
Zahiri, A.*, Heimel, K.*, Wahl, R., Rath, M., and Kämper, J. (2010) The Ustilago maydis forkhead transcription factor Fox1 is involved in the regulation of genes required for the attenuation of plant defenses during pathogenic development. in revision. *authors contributed equally
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