Project description:The fungal pathogen Ustilago maydis establishes a biotrophic relationship with its host plant maize. Hallmarks of the disease are large plant tumors in which fungal proliferation occurs. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Ustilago maydis in its host plant to get insights into the defense programs and the metabolic reprogramming needed to supply the fungus with nutrients. Keywords: time course
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:Ustilago maydis is a plant-pathogenic fungus that establishes a biotrophic relationship with its host Zea mays. The biotrophic interaction is initiated upon host penetration, and involves expansion of the host plasma membrane around hyphae, which is thought to facilitate the exchange of nutrients and virulence factors. Transcriptional regulators involved in the establishment of an infectious dikaryon and penetration into the host have been identified, however, regulators involved in the post-penetration stages remained to be elucidated. In the study we report the identification of an Ustilago maydis forkhead transcription factor, Fox1, which is exclusively expressed during biotrophic development. Deletion of fox1 results in reduced virulence and impaired tumour development in planta. Microarray analyses of Δfox1-infected plant tissue identified Fox1 as a transcriptional activator, involved in the expression of secreted effectors required for virulence. Maize plants were infected with a mixture of either FB1 and FB2 (wild-type), or FB1∆fox1 and FB2∆fox1 crossings, to measure the impact of fox1 on pathogenic development. Early Golden Bantam maize plants were grown in a phytochamber in a 15h/9h light-dark cycle; light period started/ended with 1h ramping of light intensity. Maize plants were kept at 28°C (light) and 20° (dark). Plantlets were individually sown in pots with potting soil (Fruhstorfer Pikiererde) and infected 7 days after sowing, 1 h before end of the light period. Infected leaf tumor material from at least 10 plants was collected 5 days post infection, 1 h before the end of the light period and directly frozen in liquid nitrogen for RNA-extraction. RNA samples were extracted from infected leaf tissue 5 days after infection.
Project description:The coding transcriptomes of filamentous cultures of the maize smut fungus Ustilago maydis and their extracellular vesicles (EVs) were compared. Protein-coding transcripts relatively enriched in EVs versus filament cells were identified and examined to identify potentially functional mRNA cargos of U. maydis EVs.
Project description:The fungal pathogen Ustilago maydis establishes a biotrophic relationship with its host plant maize. Hallmarks of the disease are large plant tumors in which fungal proliferation occurs. Plants have developed various defense pathways to cope with pathogens. We used microarrays to detail the global programme of gene expression during the infection process of Ustilago maydis in its host plant to get insights into the defense programs and the metabolic reprogramming needed to supply the fungus with nutrients. Experiment Overall Design: In three independent experiments plants were infected with the solopathogenic U. maydis strain SG200. Samples from infected leaves were taken at 12 and 24 hours post infection, as well as 2, 4 and 8 days post infection. Samples from uninfected control plants were taken at the same time points.
Project description:Ustilago maydis, the causal agent of corn smut disease, is a dimorphic fungus alternating between a saprobic haploid budding form, and an obligate pathogenic filamentous dikaryon. Maize responds to U. maydis colonization by producing highly modified tumorous structures and it is only within these plant galls that the fungus sporulates giving rise to melanized sexual spores, the teliospores. Previously we identified a regulatory protein from the APSES family of transcription factors, which we named Ust1, whose absence in yeast cells led to filamentous growth and the production of highly pigmented spore-like structures in culture. In this study, we analyzed the transcriptome of a ∆ust1 deletion mutant.
Project description:Ustilago maydis is a plant-pathogenic fungus that establishes a biotrophic relationship with its host Zea mays. The biotrophic interaction is initiated upon host penetration, and involves expansion of the host plasma membrane around hyphae, which is thought to facilitate the exchange of nutrients and virulence factors. Transcriptional regulators involved in the establishment of an infectious dikaryon and penetration into the host have been identified, however, regulators involved in the post-penetration stages remained to be elucidated. In the study we report the identification of an Ustilago maydis forkhead transcription factor, Fox1, which is exclusively expressed during biotrophic development. Deletion of fox1 results in reduced virulence and impaired tumour development in planta. Microarray analyses of Δfox1-infected plant tissue identified Fox1 as a transcriptional activator, involved in the expression of secreted effectors required for virulence.
Project description:mRNAs comparison between Ustilago maydis wild type grown in diluted YEPS (control) and in cell-free supernatants of Ustilago maydis wild type treated with H202 in two different concentrations (0.4% and 0.7%).
Project description:A homologue of the transcriptional repressor ScNrg1 described previously in the budding yeast and Candida albicans NRG1 wich plays an essential role in repressing hyphal development in both Saccharomyces cerevisiae and C. albicans, was found in Ustilago maydis. In S. cerevisiae it regulates a set of stress-responsive genes, also in Cryptococcus neoformans is involved in pathogenesis. In this work, we describe the effect of the absence of the U. maydis NRG1 gene in cell response to acid pH, mannosylerithritol lipids production, and cellular response to several stressful conditions. In U. maydis, NRG1 is required for filamentous growth and appears to be essential to respond to pH changes, and oxidative stress accurately. By comparing gene expression in a wild type strain versus nrg1 mutant strain of the fungus trough RNA_Seq analyses, it turned out to act as transcriptional factor altering the expression of 368 genes (205 up-regulated, 163 downregulated). Most relevant cellular processes affected by NRG1 are osmotic stress pathway, pH response, internal environmental sensor mechanism, represented by the genes Hog1, Rim101, and WCO1 respectively, also, all the genes present in the mannosylerithritol lipids production pathway, even under conditions not favorable for the production of glycolipids. Among previous specific functions described before for this transcriptional regulator as a glucose repressor, it seems to have an important role in metabolic adaptation, cellular transport, cell rescue defense and interaction with the environment.