Fusarium langsethiae infection and mycotoxin production in oats (PhD)
About this project
This investigation aimed to identify and understand the fungus responsible for the production of HT-2 and T-2 mycotoxins in UK oats; Fusarium langsethiae was found to be the causal species. A quantitative competitive PCR (QC-PCR) and a real-time PCR assay for quantifying F. langsethiae biomass in plant material were successfully developed. Real-time PCR was found to have a wider range of quantification than QCPCR.
In glasshouse experiments, point inoculation technique and high spore load (106 spores ml-1) were found to significantly increase (P = 0.036 and 0.016 respectively) the level of F. langsethiae infection in oat panicles. HT-2 and T-2 appeared to increase in line with the level of infection. For both glasshouse and field experiments, all inoculation methods failed to achieve high levels of infection and high levels of HT-2 and T-2 observed in some commercial fields.
Detached leaf assays showed some host preference of F. langsethiae towards oats than wheat. Lesion lengths were longest on leaves of an oat cultivar (Gerald) that has been reported to accumulate highest HT-2 and T-2 and shortest on leaves of the cultivar (Millennium) reported to accumulate the lowest levels of these mycotoxins.
Fusarium langsethiae was not found to be a seedling blight pathogen of oats and wheat in a controlled environment study comparing its pathogenicity with those of known Fusarium and Microdochium species. Fusarium langsethiae is therefore unlikely to reduce crop stand and yield where infected seeds are sown.
Fusarium langsethiae failed to produce visual symptoms in infected oat panicles or wheat ears in all experiments and in commercial oat fields surveyed. However, all evidence indicates that it is responsible for high concentrations of HT-2 and T-2 in oats, consequently the presence of this fungus in oats is important in human and animal health.