TY - JOUR T1 - A pair of effectors encoded on a conditionally dispensable chromosome of <em>Fusarium oxysporum</em> suppress host-specific immunity JF - bioRxiv DO - 10.1101/2020.10.06.329052 SP - 2020.10.06.329052 AU - Yu Ayukawa AU - Shuta Asai AU - Pamela Gan AU - Ayako Tsushima AU - Yasunori Ichihashi AU - Arisa Shibata AU - Ken Komatsu AU - Petra M. Houterman AU - Martijn Rep AU - Ken Shirasu AU - Tsutomu Arie Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/10/07/2020.10.06.329052.abstract N2 - Many plant pathogenic fungi contain conditionally dispensable (CD) chromosomes that are associated with virulence, but not growth in vitro. Virulence-associated CD chromosomes carry genes encoding effectors and/or host-specific toxin biosynthesis enzymes that may contribute significantly to determining host specificity. Fusarium oxysporum causes devastating diseases of more than 100 plant species. Among a large number of host-specific forms, F. oxysporum f. sp. conglutinans (Focn) can infect Brassicaceae plants including Arabidopsis and cabbage. Here we show that Focn has multiple CD chromosomes involved in virulence but also in vegetative growth, which is an atypical feature of CD chromosomes. We identified specific CD chromosomes that are required for virulence on Arabidopsis, cabbage, or both, and describe a pair of effectors encoded on one of the CD chromosomes that is required for suppression of Arabidopsis-specific phytoalexin-based immunity. The effector pair is highly conserved in F. oxysporum isolates capable of infecting Arabidopsis, but not of other plants. This study provides insight into how host specificity of F. oxysporum may be determined by a pair of effector genes on a transmissible CD chromosome.Competing Interest StatementThe authors have declared no competing interest. ER -