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POSTERS: Biotechnology and genetic engineering

Transgenic Arabidopsis expressing a modified plant thionin enhanced resistance to Fusarium graminearum
Guixia Hao - USDA/ARS/NCAUR. Hye-Seon Kim- USDA/ARS, Matthew Bakker- USDA ARS

In our previous studies, we showed that transgenic tobacco and citrus plants expressing a modified thionin (Mthionin) markedly enhanced resistance to disease incited by bacterial pathogens including Pseudomonas syringae tabaci, Xanthomonas citri and Candidatus Liberibacter asiaticus. The fungal pathogen Fusarium graminearum causes Fusarium head blight (FHB) on wheat and barley. FHB causes yield reductions and contamination of grain with trichothecene mycotoxins. Fusarium graminearum can infect the model plant Arabidopsis. The aim of this study is to investigate whether overexpression of the Mthionin in Arabidopsis can increase resistance to F. graminearum. Transgenic Arabidopsis plants expressing the Mthionin were generated by Agrobacterium-mediated floral dip transformation. Expression of the transgene was evaluated by reverse transcriptase quantitative PCR analysis. Detached leaves expressing the Mthionin displayed less severe disease symptoms compared to transgenic controls expressing GUS. When infiltrated with a F. graminearum strain expressing GFP, leaves expressing the Mthionin reduced fungal spore germination and growth compared with leaves expressing GUS. Microbiome profiling demonstrated broad similarity in microbiome structure between transgenic Arabidopsis expressing the Mthionin or GUS, although a small number of taxa differed significantly in relative abundance among transformants. Our data indicate that the Mthionin is a promising candidate for producing transgenic crops with increased FHB resistance and ultimately reduced mycotoxin contamination.