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Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and
Stefan G Amyotte1, Xiaoping Tan, Kayla Pennerman
1University of Western Ontario, London, ON, Canada.
BMC Genomics
|July 18, 2012
Summary
Transposable elements (TEs) are key drivers of genetic diversity in Verticillium fungi, which lack sexual reproduction. This study identifies active TEs in Verticillium dahliae and Verticillium albo-atrum, revealing their role in genome evolution and variation.
Area of Science:
- Genomics
- Molecular Biology
- Plant Pathology
Background:
- Verticillium dahliae (Vd) and Verticillium albo-atrum (Va) cause destructive vascular diseases in crops.
- Absence of sexual reproduction suggests somatic mutation and transposable elements (TEs) generate genetic diversity.
- Comparative genomics revealed lineage-specific (LS) regions in VdLs.17 due to TE insertions.
Purpose of the Study:
- Analyze Class I retrotransposons and Class II DNA transposons in Verticillium genomes.
- Investigate the distribution of these mobile elements across different Vd and Va isolates.
- Determine the activity and evolutionary impact of TEs in Verticillium.
Main Methods:
- Whole genome comparative analysis of VdLs.17 and VaMs.102.
- Identification and characterization of Class I and Class II TEs.
- Analysis of TE distribution in various Vd and Va isolates.
- Assessment of TE transcription and mutation events (RIP).
Main Results:
- Identified 56 complete retrotransposons (Gypsy, Copia, LINE-like) and 34 DNA transposons (Tc1/mariner, Activator, Mutator) in VdLs.17.
- Copia and Tc1/mariner elements were abundant and identical, while Activator and Mutator were divergent.
- Most identified TEs were transcriptionally active, with some Gypsy elements showing repeat-induced point mutation (RIP).
- Significant variation in TE presence was observed across surveyed strains; VaMs.102 lacked complete DNA transposons.
Conclusions:
- Copia, Gypsy, and Tc1/mariner-like transposons are widespread in Vd and Va.
- Potentially active retroelements and DNA transposons were identified in VdLs.17.
- TEs diversified, amplified, and were potentially acquired via horizontal transfer, contributing to genomic variation.
- Biased TE insertion and patchy distribution highlight TEs as major drivers of intra- and inter-specific variation in Verticillium.
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