Real-time PCR detection of Fusarium species in Swedish oats and correlation to T-2 and HT-2 toxin content

Abstract

Contamination of Fusarium moulds and subsequent production of mycotoxins is a common problem in cereals grown in Northern Europe. Oats is the third most important cereal crop in Sweden and is commonly contaminated by Fusarium. To date there are no published reports on the distribution of trichothecene-producing Fusaria in Swedish oats and correlation to T-2 and HT-2, the two most dominant toxins. Identification of Fusarium species by traditional methods requires specific skill and experience and quantification of specific species is not possible. Using modern molecular methods such as real-time PCR both identification and quantification of specific Fusarium species are possible directly from the food or feed samples. In this study, specific methods for Fusarium langsethiae, Fusarium sporotrichioides, Fusarium graminearum, Fusarium culmorum and Fusarium poae as well as for the total amount of DNA from trichothecene-producing species were evaluated with respect to precision, robustness and efficiency and then used in the analysis of oat samples. Sixty-two oat samples were taken from field trial harvests from 2006-2008 in the central and southern parts of Sweden and analysed for the presence of Fusarium species by using species-specific real-time PCR-based methods with TaqMan or SYBR Green biochemistry. The T-2 and HT-2 toxin content was analysed by gas chromatography with electron capture detection of the toxins' pentafluoropropyl derivatives. The results showed that F. langsethiae and F. poae were the most dominant Fusarium species among those tested in Swedish oats during this period. The DNA level of F. langsethiae correlated well with the level of T-2 and HT-2 toxin (r=0.7), indicating that this species was the most important producer of T-2 and HT-2 toxins in Swedish oats during the sampling period (2006 to 2008). It can also be concluded that real-time PCR is a powerful tool when studying Fusarium species distribution in oats.

Associations betweenFusarium species and mycotoxins in oats and spring wheat from farmers’ fields in Norway over a six-year period

“…This is in accordance to other studies (Bernhoft et al, 2010;Edwards, 2009;Fredlund et al, 2010), and may indicate that the HT-2 and T-2 producers have different environmental requirements and/or epidemiology than the DON producers (Edwards, 2009;Xu et al, 2014). Based on the inverse relationship detected between HT-2 and DON in UK oats, Edwards (2009) suggested a mutual exclusion between DON and HT-2 producers.…”

“…A higher occurrence of F. langsethiae in Norwegian oats compared to spring wheat was also documented in the period 2002(Bernhoft et al, 2010. Furthermore, positive associations between HT-2 + T-2 and F. langsethiae, as detected in our study, are reported in several studies of oats from Northern Europe (Bernhoft et al, 2010;Edwards et al, 2012;Fredlund et al, 2010Fredlund et al, , 2013. Despite the high association detected between HT-2 + T-2 content and F. langsethiae DNA in oats in our study, the level of F. langsethiae could not account for more than 51% of the total variation in HT-2 + T-2.…”

“…However, the more toxic trichothecenes T-2 and HT-2 toxin (T-2 and HT-2) are also often recorded, particularly in barley and oats (Aamot et al, 2013;Bernhoft et al, 2010;Langseth et al, 1999). A poor association is often observed between the concentration of HT-2 + T-2 and DON in oats (Bernhoft et al, 2010;Edwards, 2009;Fredlund et al, 2010), which may indicate that the HT-2 and T-2 producers have different environmental requirements and/or epidemiology than the DON producers (Edwards, 2009;Xu et al, 2014). In addition to the above mentioned trichothecenes, Fusarium toxins such as zearalenone (ZEA), moniliformin (MON), enniatins (ENNs) and beauvericin (BEA) are also frequently detected in Norwegian grains (Bernhoft et al, 2010;Uhlig et al, 2004Uhlig et al, , 2006Uhlig et al, , 2013.…”

Identification and Characterization of Spontaneous Auxotrophic Mutants in Fusarium langsethiae

“…Generally, a good correspondence was noted between DNA of F. langsethiae and the T-2/HT-2 toxins detected in grain samples [43,44,45,46,47]. …”

Identification and Characterization of Spontaneous Auxotrophic Mutants in <em>Fusarium langsethiae</em>

“…langsethiae is frequently detected in grains when using species-specific primers; quantitative PCR offers an efficient estimation of the biomass of individual species. Generally, a good correspondence was noted between DNA of F. langsethiae and the T-2/HT-2 toxins detected in grain samples [43][44][45][46][47].…”