Invited Presenter
Guixia Hao
1. Mycotoxin Prevention and Applied Microbiology Research Unit, NCAUR, USDA-ARS, Peoria, IL, USA
Corresponding Author: Guixia Hao, guixia.hao@usda.gov
Hao, Guixia
Fusarium graminearum causes Fusarium head blight (FHB) on wheat, barley,
and other small grains. During infection, the pathogen produces
harmful trichothecenes, predominantly deoxynivalenol (DON), which functions as a virulence factor to promote FHB
spread within the wheat head. In addition, F.
graminearum secretes hundreds of putative effectors that interfere with
plant immunity and promote disease development. Our goal is to identify and functionally
characterize effectors that are critical for F. graminearum pathogenesis and to evaluate their potential as targets for FHB and
mycotoxin management. To this end, we investigated the expression
profiles of more than 80 F. graminearum
effector-coding genes during wheat head infection and observed
distinct temporal induction
patterns. From these candidates, we
selected over 20 highly induced effectors, generated deletion mutants and
performed FHB virulence assays. Several effectors, such as FGSG_03598, play a
significant role in facilitating FHB spread, whereas others, including
FGSG_04848, contribute to initial infection in wheat and barley. FgNls1was
found to influence both initial infection and disease spread. To explore potential functions of these effectors, selected
effectors were transiently expressed in Nicotiana
benthamiana leaves or heterologously expressed
in yeast for function analysis. Furthermore, we applied RNA interference (RNAi)
targeting FgNLS1 and TRI5 to reduce FHB severity and mycotoxin
accumulation. Silencing these genes markedly reduced both FHB severity and toxin
contamination. Collectively, our findings highlight key effectors and virulence
genes required for F. graminearum infection and underscore the promise
of RNAi‑based approaches for controlling FHB and reducing mycotoxin
contamination in cereal crops.
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