Simultaneous real-time PCR detection of Fusarium asiaticum, F. ussurianum and F. vorosii, representing the Asian clade of the F. graminearum species complex

- PCR assay was able to detect pathogens within the Asian clade of F. graminearum species complex (FGSC).
- Asian clade of the FGSC was not detected in UK grain samples.
- F. graminearum s.s. was detected in UK samples using PCR but presence of other FGSC members cannot be ruled out.
- Chinese grain samples tested positive for Asian clade of the FGSC and F. graminearum s.s.
- F. asiaticum and F. graminearum s.s. were isolated from Chinese samples.

Due to the repeated discovery of new members of the Fusarium graminearum species complex (FGSC), some of the F. graminearum sensu stricto (s.s.)-specific qPCR assays developed to date have since been shown to be non-specific. In this study, a probe-based qPCR method was developed, targeting a sterol 14-alpha demethylase (CYP51) paralogue, CYP51C unique to the genus Fusarium, for the simultaneous detection of F. asiaticum, F. ussurianum and F. vorosii. Specificity of the assay was demonstrated for a wide range of Fusarium species, including all tested FGSC members (n = 6), originating from different hosts and geographic regions. Alongside a previously published assay for detection of F. graminearum, we were able to show that members of the Asian clade of the FGSC (i.e. F. asiaticum, F. ussurianum and F. vorosii) were the primary etiological agent in wheat seeds samples originating from Central-East China. The grain samples from the UK tested negative for the presence of the FGSC's Asian clade and positive for presence of F. graminearum. It is likely that only F. graminearum s.s. is present in the UK, but the presence of other FGSC members cannot be ruled out and need further investigation.