Molecular detection ofFusarium subglutinans, the causal organism of internal fruit rot in greenhouse peppers

Internal fruit rot of sweet peppers, caused by Fusarium subglutinans is a new disease found in commercial greenhouses in British Columbia and Alberta, which causes considerable yield losses. Experiments were conducted to develop a rapid and accurate assay for detection of F. subglutinans, by dot-blot hybridization. Internal transcribed spacers 1 (ITS1) and 2 (ITS2) and 5.8S rDNA were amplified by polymerase chain reaction, using universal primers, and a dot-blot assay was employed to detect the pathogen in culture and in the host. Among six probes tested, three (Fsub-1, Fsub-3, and Fsub-5) were selected because they differentiated F. subglutinans from other Fusarium spp. and greenhouse pathogens. Probe Fsub-3 hybridized with all F. subglutinans isolates. Fsub-1 hybridized only with F. subglutinans isolates from Monterey pine (Pinus radiata). Fsub-5 hybridized with F. subglutinans isolates from corn (Zea mays), peppers (Capsicum annuum), and Panicum miliaceum, but not with Pinus radiata isolates. None of t...