Active transpositions of DNA transposons and their evolutionary consequences in Fusarium oxysporum f. sp. lycopersici
Mobile Genetic Elements Conference 2019, Massachusetts, Amerika Birleşik Devletleri, 29 - 31 Ağustos 2019, (Yayınlanmadı)
- Yayın Türü: Bildiri / Yayınlanmadı
- Basıldığı Şehir: Massachusetts
- Basıldığı Ülke: Amerika Birleşik Devletleri
- Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Hayır
Özet
The genomes of many fungal and oomycete pathogens contain high numbers of transposable elements (TEs). In the Fusarium oxysporum species complex, lineage-specific chromosomes, which determine host-specificity, are rich in repeats and TEs. Although mobile elements have previously been linked to genome plasticity and pathogenicity, their exact contribution to adaptive evolution remains unknown. Here we have taken an experimental approach to study adaptive evolution in the tomato pathogen Fusarium oxysporum f. sp. lycopersici 4287 (Fol4287). Independently evolved populations displayed notable phenotypic differences with respect to the initial clonal isolate. The sequencing of these populations revealed genomic variation, including single nucleotide polymorphisms (SNPs), small insertion/deletions (INDELs), copy number variations, and chromosomal rearrangement events. Strikingly, more than 60% of the detected variants were TE insertions, and the majority were DNA transposons. A single hAT subfamily TE known as “miniature hornet” (Hormin) accounted for 57% of the detected transposition events. Analysis of the insertion sites revealed several cases of independent insertion events at the same loci in different evolved lineages. For example, 4 of the 5 populations passaged through rich media carried independent insertions of Hormin in a gene encoding a predicted protein with unknown function. During subsequent steps of experimental evolution, 3 of the 4 populations acquired additional nonsynonymous mutations in the velB gene encoding a subunit of the velvet complex. Most significantly, these rich media-evolved populations exhibited reduced virulence in tomato plants. Our results suggest that DNA transposons are a major short-term evolutionary force in F. oxysporum and provide new insights into the genetic mechanisms underlying host adaptation in this important fungal pathogen.