Fine-Scale Recombination Maps of Fungal Plant Pathogens Reveal Dynamic Recombination Landscapes and Intragenic Hotspots

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

Julien Y. Dutheil^3,4¹  Eva H. Stukenbrock^1,2² 

[1] Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Germany^2;Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany^1;Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany^3;Institut des Sciences de L’Évolution de Montpellier, Centre National de la Recherche Scientifique, Université Montpellier 2, 34095, France^4

关键词: genome evolution;    recombination analyses;    recombination hotspots;    fungal plant pathogens;    effectors;    Zymoseptoria;   

DOI  :  10.1534/genetics.117.300502

学科分类：医学（综合）

来源: Genetics Society of America

【 摘 要 】

Meiotic recombination is an important driver of evolution. Variability in the intensity of recombination across chromosomes can affect sequence composition, nucleotide variation, and rates of adaptation. In many organisms, recombination events are concentrated within short segments termed recombination hotspots. The variation in recombination rate and positions of recombination hotspot can be studied using population genomics data and statistical methods. In this study, we conducted population genomics analyses to address the evolution of recombination in two closely related fungal plant pathogens: the prominent wheat pathogen Zymoseptoria tritici and a sister species infecting wild grasses Z. ardabiliae . We specifically addressed whether recombination landscapes, including hotspot positions, are conserved in the two recently diverged species and if recombination contributes to rapid evolution of pathogenicity traits. We conducted a detailed simulation analysis to assess the performance of methods of recombination rate estimation based on patterns of linkage disequilibrium, in particular in the context of high nucleotide diversity. Our analyses reveal overall high recombination rates, a lack of suppressed recombination in centromeres, and significantly lower recombination rates on chromosomes that are known to be accessory. The comparison of the recombination landscapes of the two species reveals a strong correlation of recombination rate at the megabase scale, but little correlation at smaller scales. The recombination landscapes in both pathogen species are dominated by frequent recombination hotspots across the genome including coding regions, suggesting a strong impact of recombination on gene evolution. A significant but small fraction of these hotspots colocalize between the two species, suggesting that hotspot dynamics contribute to the overall pattern of fast evolving recombination in these species.

【 授权许可】

CC BY