TeloPortWrapper: A New Tool for Understanding the Dynamic World of Fungal Telomere Ends

Telomeres are repetitive DNA sequence motifs found at eukaryote chromosome ends. Telomeres help protect chromosome ends from DNA damage and promote chromosome stability. Chromosomes play important roles in aging, mutation, and cancer. Eukaryotic pathogens also use telomeres to mutate and manage virulence genes. In response to chromosome end breakage newly formed telomeres, called de novo telomeres, are formed to recreate the lost telomere and sub-telomeric regions. Magnaporthe oryzae is a fungal pathogen which causes wheat blast, a deadly plant disease in wheat. Magnaporthe oryzae is also known for its highly variable sub-regions which show high amounts of induced variability due to de novo telomere formation. This variance is associated with mutation and adaptation. Little is known about de novo telomere formation as telomeres are often underrepresented in standard sequencing assemblies. TeloPortWrapper is a new tool to collect and sort telomeric reads from the raw reads, identify and analyze de novo telomeres, and create visual result summaries. Using TeloPortWrapper on 940,225,828 reads across 14 different Magnaporthe oryzae strain genomes and aligning them to their assembled genome, it was found that a vast majority of new telomeric regions are being pulled from sections in the middle of chromosomes rather than close to the breakage point itself, as was previously assumed. Manually checking iii all the aligned reads confirmed that TeloPortWrapper is an accurate tool for collecting and analyzing de novo telomeres