Fusarium graminearum causes Fusarium head blight (FHB) on wheat and produces the trichothecene mycotoxin deoxynivalenol (DON) that promotes FHB spread and contaminates grains. Approaches that detoxify DON can lead to reduced FHB and mycotoxin contamination. Detoxification and excretion of toxic compounds are important mechanisms for organism self-protection. Our previous study showed that transgenic Arabidopsis thaliana expressing a fungal self-protection gene, F. graminearum 3-O-acetyltransferase (FgTRI101) converted mycotoxin DON to the less toxic 3-acetyl-DON (3-ADON) and excreted 3-ADON out of plant cells to protect plant growth and development. In this study, our goal is to identify the transporters for 3-ADON excretion and utilize them to enhance wheat FHB resistance. Transcriptomic studies were conducted in FgTri101 transgenic A. thaliana seedlings treated with DON (50 mg/L, 24 h) and untreated controls. Three transporter genes, including two A. thaliana detoxification genes (AtDTX1 and AtDTX3) and one ABC transporter (ABCB4), were upregulated by DON in RNA seq analyses and confirmed by RT-qPCR as well. AtDTX1 has been identified as an efflux carrier for alkaloid, antibiotics and toxic compounds. Therefore, an A. thaliana mutant line with AtDTX1 disrupted was obtained. Toxicity analysis showed Atdtx1 mutant seedlings were sensitive to DON, suggesting the Atdtx1 mutant line lacks self-protection. Further, FgTRI101 was introduced into the Atdtx1 mutant line by floral dip transformation. Transgenic A. thaliana plants expressing FgTR1101 in the Atdtx1 mutant background were obtained and used for further analysis. Our data showed that AtDTX1 and at least one additional transporter are involved in 3-ADON excretion. Further identification of the second potential transporter for 3-ADON are underway.    
  

This material is based upon work supported by the U.S. Department of Agriculture. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.