Project description:Gene expression of FB2 wt in minimal medium with 2 percent arabinose or glucose after 24h of growth was compared with the conditional promoter regulated strain Pcrg1:grx4 (#55). Glucose is a repressor of this promoter while arabinose acts as inducer. Grx4 was initially pre-depleted during growth on MM with glucose over night. Afterwards cells were transferred to MM with either glucose or arabinose and cells were collected after 24h. 3 biological repeats were performed for each strain and each condition. Cells were flash frozen and used to isolate total RNA. RNA sequencing was done by Genewiz. DEG’s between wt and mutant for the different conditions were obtained. Iron regulated genes such as the high affinity uptake system and the siderophore system of Ustilago maydis were repressed in the Pcrg1:grx4 (#55) strain when grown in glucose. Expression of these genes were similar for wt and the conditional strain when grown in arabinose. Grx4 was identified as an essential gene in Ustilago maydis which regulates the iron regulon and related genes.
Project description:Goals: characterization of the transcription factor Ros1 in Ustilago maydis Methods: generation of deletion mutants, microscopic observations, ectopic expression of ros1, identification of Ros1 regulated genes by RNAseq and ChIP sequencing Results: Ros1 is not involved in plant colonization but is essential to trigger sporogenesis during late stages of infection. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of sporogenesis. Transcriptional profiling and ChIP seq analyses revealed that Ros1 affects the expression of about 30 % of all U. maydis genes with 40% being direct targets. Cell wall remodeling and plasma membrane modifications are among the processes affected by Ros1 dependent regulation. Interestingly a large number of b-dependent genes including transcription factors and effector genes involved in biotrophy establishment were downregulated by Ros1 while a subset of novel “late effectors” were upregulated. Taken together our results indicate that Ros1 is a master regulator of sporogenesis in U. maydis and that the switch to sporogenesis is accompanied by the differential regulation of 75% of the effector genes.
Project description:Goals: characterization of the transcription factor Ros1 in Ustilago maydis Methods: generation of deletion mutants, microscopic observations, ectopic expression of ros1, identification of Ros1 regulated genes by RNAseq and ChIP sequencing Results: Ros1 is not involved in plant colonization but is essential to trigger sporogenesis during late stages of infection. Premature expression of ros1 revealed that Ros1 counteracts the b-dependent filamentation program and induces morphological alterations resembling the early steps of sporogenesis. Transcriptional profiling and ChIP seq analyses revealed that Ros1 affects the expression of about 30 % of all U. maydis genes with 40% being direct targets. Cell wall remodeling and plasma membrane modifications are among the processes affected by Ros1 dependent regulation. Interestingly a large number of b-dependent genes including transcription factors and effector genes involved in biotrophy establishment were downregulated by Ros1 while a subset of novel “late effectors” were upregulated. Taken together our results indicate that Ros1 is a master regulator of sporogenesis in U. maydis and that the switch to sporogenesis is accompanied by the differential regulation of 75% of the effector genes.
Project description:In the phytopathogenic Basidiomcete Ustilago maydis, sexual and pathogenic development are tightly connected and controlled via the b-mating type locus. The b-mating type locus encodes two homeodomain transcription factors, bE and bW, which form an active heterodimeric complex when they are derived from different b-alleles. Rbf1 encodes a zinc-finger transcription factor that is expressed upon formation of an active bE/bW heterodimer. To identify gene regulated by rbf1 independently from b, the b mating type locus was replaced by a copy of rbf1 under control of the arabinose-inducible crg1 promoter (strain CP27). Samples were taken 5h after induction of rbf1 gene expression. Strain JB2, carrying a deletion of the b-locus, was used as control.