PT  - JOURNAL ARTICLE
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
TI  - A pair of effectors encoded on a conditionally dispensable chromosome of <em>Fusarium oxysporum</em> suppress host-specific immunity
AID  - 10.1101/2020.10.06.329052
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.10.06.329052
4099  - http://biorxiv.org/content/early/2020/10/07/2020.10.06.329052.short
4100  - http://biorxiv.org/content/early/2020/10/07/2020.10.06.329052.full
AB  - 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.