Killer meiotic driver prevents chromosome loss and enhances fitness in a fungal pathogen
- 1Universidad de Cordoba, Department of Genetics
Abstract
Fungal pathogens often carry dispensable chromosomes (DCs) that confer a selective advantage in adverse environments or during host infection but can be spontaneously lost under non-selective conditions. How DCs are maintained in evolving populations remains poorly understood. Here we show that a meiotic driver known as Spore Killer (spok), located on a giant Starship transposon, limits spontaneous loss of a conserved DC in the cross-kingdom pathogen Fusarium oxysporum. Transfer of a functional spok gene, but not of a killing-deficient mutant allele, to a mitotically unstable DC significantly reduced its loss rate, while spok deletion from a stably maintained DC increased loss frequency. Competition experiments between isogenic strains carrying a functional or a killing-deficient spok allele revealed a dramatic fitness gain conferred by Spok killing activity, which required transmission by hyphal fusion. Thus, spoks and their Starship carriers benefit fungal hosts by preventing DC loss and preserving long-term metabolic and pathogenic plasticity.
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BibTeX
@misc{pueblaplanas2026killer,
title = {{Killer meiotic driver prevents chromosome loss and enhances fitness in a fungal pathogen}},
author = {G. Puebla-Planas and A. Doddi and D. H. Ayhan and P. Gutierrez-Escribano and L.-J. Ma and M. S. Lopez-Berges and A. Di Pietro},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.04.756499},
url = {https://www.biorxiv.org/content/10.64898/2026.10.04.756499v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Killer meiotic driver prevents chromosome loss and enhances fitness in a fungal pathogen
AU - G. Puebla-Planas
AU - A. Doddi
AU - D. H. Ayhan
AU - P. Gutierrez-Escribano
AU - L.-J. Ma
AU - M. S. Lopez-Berges
AU - A. Di Pietro
PY - 2026
DA - 2026/10/04
PB - bioRxiv
DO - 10.64898/2026.10.04.756499
UR - https://www.biorxiv.org/content/10.64898/2026.10.04.756499v1
AB - Fungal pathogens often carry dispensable chromosomes (DCs) that confer a selective advantage in adverse environments or during host infection but can be spontaneously lost under non-selective conditions. How DCs are maintained in evolving populations remains poorly understood. Here we show that a meiotic driver known as Spore Killer (spok), located on a giant Starship transposon, limits spontaneous loss of a conserved DC in the cross-kingdom pathogen Fusarium oxysporum. Transfer of a functional spok gene, but not of a killing-deficient mutant allele, to a mitotically unstable DC significantly reduced its loss rate, while spok deletion from a stably maintained DC increased loss frequency. Competition experiments between isogenic strains carrying a functional or a killing-deficient spok allele revealed a dramatic fitness gain conferred by Spok killing activity, which required transmission by hyphal fusion. Thus, spoks and their Starship carriers benefit fungal hosts by preventing DC loss and preserving long-term metabolic and pathogenic plasticity.
ER -