Cloning and characterization of a novel UDP-glycosyltransferase gene induced by DON from wheat

Fusarium head blight (FHB), caused primarily by Fusarium graminearum, is a destructive disease of wheat throughout the world. However, the mechanisms of host resistance to FHB are still largely unclear. Deoxynivalenol (DON) produced by F. graminearum which enhances the pathogen to spread could be converted into inactive form D3G by UDP-glycosyltransferases (UGTs). A DON responsive UGT gene, designated as TaUGT4, was first cloned from wheat in this study. The putative open reading frame (ORF) of TaUGT4 was 1 386 bp, encoding 461 amino acids protein. TaUGT4 was placed on chromosome 2D using a set of nulli-tetrasomic lines of wheat cultivar Chinese Spring (CS). When fused with eGFP at C terminal, TaUGT4 was shown to localize in cytoplasm of the transformed tobacco cells. The transcriptional analysis revealed that TaUGT4 was strongly induced by F. graminearum or DON in both of FHB-resistant cultivar Sumai 3 and susceptible cultivar Kenong 199, especially in Sumai 3 under DON treatment. Similar increase of TaUGT4 expression was observed in Sumai 3 and Kenong 199 in response to salicylic acid (SA) treatment. But interestingly, the transcripts level of TaUGT4 in Sumai 3 showed significantly higher than that in Kenong 199 after treated with methyl jasmonate (MeJA). According to the expression patterns, TaUGT4 might lead to different effects between FHB-resistant genotype and susceptible genotype in the process against F. graminearum inoculation. It had also been discussed in this paper that JA signaling pathway might play a significant role in the resistance against F. graminearum compared to SA signaling pathway.