Fusarium langsethiae artificial oat infection under field conditions
Kane D'Arcy Cusack*
Fusarium langsethiae is a recently described species belonging to the complex of fungi causing Fusarium Head Blight in small grain cereals. The epidemiology of this species is poorly understood compared with the more extensively studied species of the Fusarium genus such as F. graminearum. However, it is known to be a potent producer of T-2 and HT-2 trichothecene mycotoxins and has been implicated in the rising levels of these toxins found in European cereals, particularly in oats for which F. langsethiae shows host preference. Infection under experimental conditions has mostly relied on natural infection in the field or artificial inoculation in glasshouse conditions. Here, we describe a method for field inoculation of F. langsethiae in oats under the Irish environment. The field trial consisted of 190 oat varieties with 10 checks planted in 1.5m rows in a randomised complete block design with 2 replications. Each variety received three separate inoculations at Zadok’s growth stages 55, 60 and 65, using a spore suspension consisting of a mix of three isolates of F. langsethiae at 1 x 105 conidia/ml in Tween 20 (0.02% v/v in sterile distilled water). Each inoculation consisted of 100ml of spore suspension distributed across each variety row using a pressurised hand-sprayer. Checks received the same volume of Tween 20 solution. After each inoculation, a misting irrigation system suspended above the trial area was used to maintain a high humidity conducive to fungal growth. Mist was produced in the plot area at 20-minute intervals for up to 4 hours after inoculation, depending on prevailing weather conditions. At harvest, 30 main tillers of each variety were hand harvested, cleaned, dried and milled. T-2 and HT-2 contamination and F. langsethiae infection analyses will be performed by LC/MS Q-TOF and qPCR, respectively. Preliminary data have successfully shown F. langsethiae infection. Following completion of data analysis, a genome-wide association study for resistance to F. langsethiae infection will be performed.
We would like to acknowledge BBSRC-SFI for funding the current research.