Van Wyk, StephanieWingfield, Brenda D.De Vos, LieschenVan der Merwe, Nicolaas Albertus (Albie)Santana, Quentin C.Steenkamp, Emma Theodora2020-01-282020-01-282019-12Van Wyk, S., Wingfield, B.D., De Vos, L. et al. 2019, 'Repeat-induced point mutations drive divergence between Fusarium circinatum and its close relatives', Pathogens, vol. 8, no. 4, art. 298, pp. 1-21.2076-0817 (online)10.3390/pathogens8040298http://hdl.handle.net/2263/72996The Repeat-Induced Point (RIP) mutation pathway is a fungal-specific genome defense mechanism that counteracts the deleterious effects of transposable elements. This pathway permanently mutates its target sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence of RIP in the pitch canker pathogen, Fusarium circinatum, and its close relatives in the Fusarium fujikuroi species complex (FFSC). Our results showed that the examined fungi all exhibited hallmarks of RIP, but that they differed in terms of the extent to which their genomes were affected by this pathway. RIP mutations constituted a large proportion of all the FFSC genomes, including both core and dispensable chromosomes, although the latter were generally more extensively affected by RIP. Large RIP-affected genomic regions were also much more gene sparse than the rest of the genome. Our data further showed that RIP-directed sequence diversification increased the variability between homologous regions of related species, and that RIP-affected regions can interfere with homologous recombination during meiosis, thereby contributing to post-mating segregation distortion. Taken together, these findings suggest that RIP can drive the independent divergence of chromosomes, alter chromosome architecture, and contribute to the divergence among F. circinatum and other members of this economically important group of fungi.en© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Fusarium circinatumLineage divergenceRepeat-induced point (RIP)MutationsSegregation distortionGenome evolutionFusarium fujikuroi species complex (FFSC)Article