Extraordinary Genome Instability and Widespread Chromosome Rearrangements During Vegetative Growth

Genetics: A Periodical Record of Investigations Bearing on Heredity and Variation

article

Mareike Möller¹  Michael Habig¹  Michael Freitag³  Eva H. Stukenbrock¹ 

[1] Environmental Genomics, Christian-Albrechts University, D-24118 Kiel, Germany;Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany;Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305

关键词: chromosome loss;    mitosis;    fungal pathogen;    experimental evolution;   

DOI  :  10.1534/genetics.118.301050

学科分类：医学（综合）

来源: Genetics Society of America

【 摘 要 】

The haploid genome of the pathogenic fungus Zymoseptoria tritici is contained on “core” and “accessory” chromosomes. While 13 core chromosomes are found in all strains, as many as eight accessory chromosomes show presence/absence variation and rearrangements among field isolates. The factors influencing these presence/absence polymorphisms are so far unknown. We investigated chromosome stability using experimental evolution, karyotyping, and genome sequencing. We report extremely high and variable rates of accessory chromosome loss during mitotic propagation in vitro and in planta . Spontaneous chromosome loss was observed in 2 to >50% of cells during 4 weeks of incubation. Similar rates of chromosome loss in the closely related Zymoseptoria ardabiliae suggest that this extreme chromosome dynamic is a conserved phenomenon in the genus. Elevating the incubation temperature greatly increases instability of accessory and even core chromosomes, causing severe rearrangements involving telomere fusion and chromosome breakage. Chromosome losses do not affect the fitness of Zymoseptoria tritici in vitro , but some lead to increased virulence, suggesting an adaptive role of this extraordinary chromosome instability.

【 授权许可】

CC BY