Evolution and Genomics of Plants pathogen Interactions (EGIP)
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Biologie et Gestion des Risques en agriculture (BIOGER), INRAE UMR 1290, Université Paris-Saclay, AgroParisTech
Campus AgroParisTech, Avenue Louis Bretignières,
78850, Thiverval-Grignon, France
Scientific Interest
We are using transposable elements (TEs) as tools for insertional mutagenesis in fungi. The TC1-mariner impala from the fungus Fusarium oxysposrum was introduced in the wheat fungal pathogen Zymoseptoria tritici. A vector containing an autonomous copy of impala inserted in the 5’UTR of A. nidulans nitrate reductase gene was used to select nitrate-utilizing revertants (Nia+). Most Nia+ Z. tritici revertants (80%) displayed a single copy of impala inserted at a new genomic location. impala mainly inserts into genes (85%) near transcriptional start sites (TSS, 50%). impala inserted at much lower frequencies in native transposons (1%) and intergenic regions (14%). We hypothesized that impala insertion is influenced by the chromatin landscape of TE acceptor locus. Inhibition of Z. tritici histone deacetylases with trichostatin which open chromatin, increased the frequency of impala insertions in native transposons by 5-fold. Trichostatin also changed impala insertion pattern in genes (1.5 fold increase of exons/introns insertions). These experiments suggests that impala inserted preferentially near TSS because of their characteristic open chromatin landscape. This property of impala was used to develop activation tagging in fungi. A modified impala transposon carrying a strong constitutive promoter (pGpd) was inserted in the 5’UTR of A. nidulans nitrate reductase gene. This chimeric impala:Gpd transposon was able to excise and re-insert in Z. tritici genome. impala:Gpd inserted mainly in 5’UTRs and promoters of Z. tritici genes, as native impala. We are using these collection of impala revertants (native, activation tagging) to screen for pathogenicity mutants and identify novel genes involved in the infection process of Z. tritici.
We are using transposable elements (TEs) as tools for insertional mutagenesis in fungi. The TC1-mariner impala from the fungus Fusarium oxysposrum was introduced in the wheat fungal pathogen Zymoseptoria tritici. A vector containing an autonomous copy of impala inserted in the 5’UTR of A. nidulans nitrate reductase gene was used to select nitrate-utilizing revertants (Nia+). Most Nia+ Z. tritici revertants (80%) displayed a single copy of impala inserted at a new genomic location. impala mainly inserts into genes (85%) near transcriptional start sites (TSS, 50%). impala inserted at much lower frequencies in native transposons (1%) and intergenic regions (14%). We hypothesized that impala insertion is influenced by the chromatin landscape of TE acceptor locus. Inhibition of Z. tritici histone deacetylases with trichostatin which open chromatin, increased the frequency of impala insertions in native transposons by 5-fold. Trichostatin also changed impala insertion pattern in genes (1.5 fold increase of exons/introns insertions). These experiments suggests that impala inserted preferentially near TSS because of their characteristic open chromatin landscape. This property of impala was used to develop activation tagging in fungi. A modified impala transposon carrying a strong constitutive promoter (pGpd) was inserted in the 5’UTR of A. nidulans nitrate reductase gene. This chimeric impala:Gpd transposon was able to excise and re-insert in Z. tritici genome. impala:Gpd inserted mainly in 5’UTRs and promoters of Z. tritici genes, as native impala. We are using these collection of impala revertants (native, activation tagging) to screen for pathogenicity mutants and identify novel genes involved in the infection process of Z. tritici.
Thematic