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E-GEOD-43745 - Genome-wide analyses of Fusarium fujikuroi reveal complex regulation of secondary metabolism and new metabolites
Released on 1 July 2013, last updated on 9 July 2013
Investigation of whole genome gene expression of the Fusarium fujikuroi wild type IMI58289 under gibberellin-inducing and -repressing conditions. Fusarium fujikuroi is a biotechnologically important fungus due to its almost unique ability to produce gibberellic acids (GAs), a family of phytohormones. The fungus was already described about 100 years ago as the causative agent of Bakanae (foolish seedling) disease of rice. Beside GAs, the fungus is known to produce some pigments and mycotoxins, but for only eight products the biosynthetic genes are known. Here we present a high-quality genome sequence of the first member of the Gibberella fujikuroi species complex (GFC), that allowed de novo genome assembly with 12 scaffolds corresponding to the 12 chromosomes. In this work, we focused on identification of all potential secondary metabolism-related gene clusters and their regulation in response to nitrogen availability by transcriptome, proteome, HPLC-FLPC and ChIP-seq analyses. We show that most of the cluster genes are regulated in a nitrogen-dependent manner, and that expression profiles fit to proteome and ChIP-seq data for some but not all clusters. Comparison with genomes of all available Fusarium species, including the recently sequenced F. mangiferae and F. circinatum, showed only a small number of common gene clusters and provides new insights into the divergence of secondary metabolism in the genus Fusarium. Phylogenetic analyses suggest that some gene clusters were acquired by horizontal gene transfer, while others were present in ancient Fusarim species and have evolved differently by gene duplications and losses. One PKS and one NRPS gene cluster are unique for F. fujikuroi. Their products were identified by combining overexpression of cluster genes with HPLC-FLPC -based product analyses. In planta, expression studies suggest a specific role of the PKS19 product in rice infection. Our results indicate that comparative genomics together with the used genome-wide experimental approaches is a powerful tool to uncover new secondary metabolites and to understand their regulation on the transcript, protein and epigenetic levels. In this study, we hybridized in total 15 microarrays using total RNA recovered from wild-type cultures of F. fujikuroi IMI58289. Two cultures were grown on a 6 mM Gln medium. Additionally, two technical replicates were created. Four cultures were grown on a 60 mM Gln medium. Again, two technical replicates were created. On a 6 mM NO3 medium, three cultures were grown, and two cultures on a 120 mM NO3 medium, with no technical replicates. Each chip measures the expression level of 14,397 genes from F. fujikuroi IMI58289 with eight 60-mer probes.
transcription profiling by array
Ulrich Güldener <firstname.lastname@example.org>, Bettina Tudzynski, Caroline Michielse, Christian Sieber, Lena Studt, Philipp Wiemann