Experimental evolution of the fungal pathogen Fusarium oxysporum.
14th European Conference on Fungal Genetics, Tel-Aviv-Yafo, İsrail, 1 - 04 Mart 2018, (Yayınlanmadı)
- Yayın Türü: Bildiri / Yayınlanmadı
- Basıldığı Şehir: Tel-Aviv-Yafo
- Basıldığı Ülke: İsrail
- Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Hayır
Özet
Natural selection is a fundamental evolutionary process that acts on changes in a genome and results in the adaptation of a population. The most common forms of genome changes range from single nucleotide polymorphism (SNPs), small insertion/deletions (INDELs), segmental duplication, chromosomal rearrangement, to whole genome duplication. It is unknown how the changes in genome influence the evolutionary processes under different selection pressure. To answer this question, this study takes an experimental approach to observe evolving processes using the model organism, Fusarium oxysporum, a highly adaptive species complex containing mobile and lineage-specific (supernumerary) chromosomes that are rich in transposons and determines host-specific pathogenicity.
The same starting population (F. oxysporum f. sp. lycopersici strain 4287, a tomato pathogenic isolate) was passaged ten times through two distinct serial transfers in its host or on rich media plates. We have sequenced 5 populations from the end of each serial transfer.
Comparative genomics revealed the presence of segmental duplications and deletions in parts of supernumerary regions, suggesting that genome rearrangements may be a major force that shapes short-term evolution.
Retaining a relatively constant mutation rate, there is a much lower possibility to accumulate beneficial SNPs in a short time frame. However, we observed many SNPs, among these, a few could explain the loss of the pathogenicity in some populations.
Interestingly, the populations that evolved in rich media seem to lose parts of or entire supernumerary chromosomes, suggesting a high energy cost and therefore a dispensable nature and associated with these chromosomes when growing on rich media.
These results highlight that different evolutionary constraints determine the outcome when populations are adapting to different environments.