Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2019
Publication Date: 3/17/2019
Citation: Hao, G., Vaughan, M.M., McCormick, S.P. 2019. Fusarium graminearum effectors suppress plant immunity [abstract].
Technical Abstract: Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most devastating wheat and barley diseases worldwide. The disease causes significant yield loss and grain contamination with harmful trichothecenes. Pathogens frequently produce effectors that can suppress plant immunity and promote disease. F. graminearum is predicted to secrete hundreds of effectors, which may play a critical role during interactions with host plants. However, only a few F. graminearum effectors have been functionally characterized. In the current study, we selected 30 effector candidates and evaluated their expression during wheat head infection. Following whole head inoculation, tissue was collected and the expression of candidate effector genes was evaluated at multiple time points. Quantitative PCR revealed that four of the effectors were upregulated immediately after inoculation. Three effectors were induced at 36 h and reached the peak at 3 or 5 d after inoculation. The expression of FGSG_12160 was induced over 2,400-fold at 3 d after inoculation, sharing a profile similar to that of TRI5 (trichodiene synthase). Additionally, transient expression assays in Nicotiana benthamiana showed that several highly induced effectors suppressed reactive oxygen species production which is typically part of the plant defense response. Our results suggest that these highly induced effectors play a role in suppressing plant immunity which in turn promoting pathogenesis. Further investigations via mutagenesis are currently underway to determine the role of these effectors in FHB development.