Knock-down of the methyltransferase Kmt6 reliefs H3K27me3 and results in induction of cryptic and otherwise silent secondary metabolite gene clusters in Fusarium fujikuroi
Ontology highlight
ABSTRACT: Knock-down of the methyltransferase Kmt6 reliefs H3K27me3 and results in induction of cryptic and otherwise silent secondary metabolite gene clusters in Fusarium fujikuroi
Project description:Filamentous fungi produce a vast array of secondary metabolites (SMs) and some of them are applied in agriculture or pharmacology. Recent sequencing of the rice pathogen Fusarium fujikuroi revealed the presence of far more SM-encoding genes than known products. SM production is energy-consuming and thus tightly regulated, leaving the majority of SM gene clusters silent under laboratory conditions. It is now well established that one important regulatory layer in SM biosynthesis involves histone modifications that render the genes either silent or poised for transcription. In this study, we show that the majority of the putative SM gene clusters in F. fujikuroi are located within facultative heterochromatin marked by H3K27me3. In this study, we performed comparative transcriptomics of a knock-down mutant of the responsible methyltransferase Kmt6 involved in H3K27 methylation grown on either solid complete medium or solid synthetic ICI medium. Overall four so far cryptic and otherwise silent putative SM gene clusters were significantly induced in the KMT6kd strain accompanied by reduced H3K27me3 levels at the respective gene loci and accumulation of novel metabolites. One of the four putative SM gene clusters, the STC5 gene cluster, was analysed in detail and heterologous expression of the key enzyme allowed for the identification of the first pathway-specific intermediate (1R,4R,5S)-guaia-6,10(14)-diene. 2 strains were analysed in overall two conditions, and each with 3 biological replicates
Project description:Filamentous fungi produce a vast array of secondary metabolites (SMs) and some of them are applied in agriculture or pharmacology. Recent sequencing of the rice pathogen Fusarium fujikuroi revealed the presence of far more SM-encoding genes than known products. SM production is energy-consuming and thus tightly regulated, leaving the majority of SM gene clusters silent under laboratory conditions. It is now well established that one important regulatory layer in SM biosynthesis involves histone modifications that render the genes either silent or poised for transcription. In this study, we show that the majority of the putative SM gene clusters in F. fujikuroi are located within facultative heterochromatin marked by H3K27me3. In this study, we performed comparative transcriptomics of a knock-down mutant of the responsible methyltransferase Kmt6 involved in H3K27 methylation grown on either solid complete medium or solid synthetic ICI medium. Overall four so far cryptic and otherwise silent putative SM gene clusters were significantly induced in the KMT6kd strain accompanied by reduced H3K27me3 levels at the respective gene loci and accumulation of novel metabolites. One of the four putative SM gene clusters, the STC5 gene cluster, was analysed in detail and heterologous expression of the key enzyme allowed for the identification of the first pathway-specific intermediate (1R,4R,5S)-guaia-6,10(14)-diene.
Project description:We performed ChIP-seq of H3K27me3 in wild type Fusarium fujikuroi grown in synthetic ICI medium with low nitrogen conditions. Three replicates of F. fujikuroi wild-type strain were grown in low nitrogen. ChIP-Seq was performed with anti-H3K27me3 antibody.
Project description:Filamentous fungi produce a vast array of secondary metabolites (SMs) and some play a role in agriculture or pharmacology. Sequencing of the rice pathogen Fusarium fujikuroi revealed the presence of far more SM-encoding genes than known products. SM production is energy-consuming and thus tightly regulated, leaving the majority of SM gene clusters silent under laboratory conditions. One important regulatory layer in SM biosynthesis involves histone modifications that render the underlying genes either silent or poised for transcription. Here, we show that the majority of the putative SM gene clusters in F. fujikuroi are located within facultative heterochromatin marked by trimethylated lysine 27 on histone 3 (H3K27me3). Kmt6, the methyltransferase responsible for establishing this histone mark, appears to be essential in this fungus, and knock-down of Kmt6 in the KMT6kd strain shows a drastic phenotype affecting fungal growth and development. Transcription of four so far cryptic and otherwise silent putative SM gene clusters was induced in the KMT6kd strain, in which decreased expression of KMT6 is accompanied by reduced H3K27me3 levels at the respective gene loci and accumulation of novel metabolites. One of the four putative SM gene clusters, named STC5, was analysed in more detail thereby revealing a novel sesquiterpene.
Project description:Knock-down of the methyltransferase Kmt6 reliefs H3K27me3 and induces expression of cryptic otherwise silent secondary metabolite gene clusters in Fusarium fujikuroi [gene expression]
Project description:Knock-down of the methyltransferase Kmt6 reliefs H3K27me3 and results in induction of cryptic and otherwise silent secondary metabolite gene clusters in Fusarium fujikuroi [ChIP-seq]
Project description:The phytopathogenic fungus Fusarium fujikuroi is the causal agent of bakanae disease on rice due to its ability to produce gibberellins. Besides these phytohormones, F. fujikuroi is able to produce a wide range of other secondary metabolites (SMs), such as mycotoxins and pigments. Although much progress has been made in the field of secondary metabolism over the last years, the transcriptional regulation of SM biosynthetic genes is complex and far from being fully understood. Environmental conditions (e.g. nitrogen availability and pH), global and pathway-specific regulators as well as chromatin remodeling were shown to play major roles in this regulation. Here, the role of FfSge1, a homolog of the morphological switch regulators Wor1 and Ryp1 in Candida albicans and Histoplasma capsulatum, respectively, is explored with emphasis on secondary metabolism. FfSge1 is not required for conidia formation and pathogenicity, but is involved in vegetative growth. Genome-wide transcriptome analysis of the M-NM-^Tffsge1 deletion mutant compared to the wild type revealed that FfSge1 is a global regulator of secondary metabolism in F. fujikuroi that activates the expression of several SMs. In addition, FfSge1 is also required for expression of a yet uncharacterized SM gene cluster containing a noncanonical non-ribosomal peptide synthetase. Investigation of whole genome gene expression of the Fusarium fujikuroi wild type IMI58289, M-NM-^Tffsge1 mutant under nitrogen starvation and nitrogen sufficient conditions. In this study we hybridized in total 8 microarrays using total RNA recovered from a wild-type culture of F. fujikuroi IMI58289 and M-NM-^Tffsge1 mutant culture. All cultures were grown on a 6 mM Gln (10%) and a 60 mM Gln medium (100%). For each combination of culture and medium a biological replicate was created. Each chip measures the expression level of 14,397 genes from F. fujikuroi IMI58289 with eight 60-mer probes. Please note that the wild type samples have been published as part of the GEO accession GSE43745, but re-analyzed with the M-NM-^Tffsge1 mutant samples in the current study.