Infection of green fluorescence protein-tagged Fusarium graminearum on wheat and barley spikes

Fusorium head blight (FHB), mainly caused by Fusarium graminearum, is a very serious disease in wheat and barley production area. FHB epidemics cause yield decreases and production Of mycotoxin that renders the grain useless for flour and mail products. Understanding the infection mechanism of F. graminearum plays all important role for (lie disease control. In present study, green fluorescence protein (GFP)-tagged were infected (to wheat and barley varieties by single floret injection and screened via GFP signal. Results showed similar infection pattern of F graminearum on both wheat and barley. Pathogen geminated in the inoculated spikelets, grew on the top of ovary or between lemma and palea, and extended towards and through rachis to the adjacent spikelets to infect the whole spike. When a spike of cultivar with FHB resistance was inoculated by F. graminearum, only the injected spikelet showed symptom at 6 days past Inoculation (dpi). GFP signals indicated that F. graminearum colonized only in the inoculated spikelet and stop at the compact (issue of rachilla at 6 dpi. Oil the contrary, the diseased spikelets were Lip to 5 at 6 dpi in the spike of cultivars susceptible to FHB. F. graminearum extended through compact tissue to rachis and infected to the adjacent spikelets by spreading upward and downward to adjacent florets inter- and intra- cellularly in vascular bundles and cortical tissue of the rachis.