Horizontal chromosome transfer (HCT) has been demonstrated in Fusarium oxysporum. Several pathogenic F. oxysporum strains have been used as donors in HCT experiments, while the non-pathogenic strain Fo47 has mainly been employed as a recipient. It currently remains unknown whether other non-pathogenic F. oxysporum strains are recipients of mobile chromosomes. In the present study, we investigated whether the non-pathogenic strain 08C-3B, obtained from cabbage, acquired the mobile chromosomes of F. oxysporum f. sp. conglutinans strain Cong:1-1, which infects cabbage. We detected HCT between Cong:1-1 and 08C-3B in a conidial anastomosis tube (CAT) fusion-inductive medium, yielding HCT progeny strains that carried scaffolds (SCs) 8 and 9 of Cong:1-1. These progeny strains exhibited reduced colony growth on potato dextrose agar plates and produced no symptoms on cabbage. These results suggest that SC8 and/or SC9 hinder vegetative growth, but do not confer virulence to 08C-3B. We then conducted HCT experiments to assess whether the HCT progeny strain transfers the acquired chromosomes to other strains. However, no progeny strains were obtained, suggesting that 08C-3B does not function as a donor for mobile chromosomes.
Ayukawa et al. (Thu,) studied this question.