DEOXYNIVALENOL DETOXIFICATION IN TRANSGENIC DURUM WHEAT CONFERS RESISTANCE TO FUSARIUM HEAD BLIGHT AND CROWN ROT DISEASES REDUCING GRAIN MYCOTOXIN CONTAMINATION
Fusarium diseases, including Fusarium head blight (FHB) and crown rot (FCR), represent major agricultural problems worldwide, causing reducti on of grain yield, quality and food safety. Grain contaminati on by Fusarium mycotoxins, mainly deoxynivalenol (DON), is responsible for health problems in humans and animals. DON acts as virulence factor during pathogenesis and its glycosylati on, performed by UDPglucosyltransferases (UGTs) and resulti ng in DON-3-glucoside (D3G) producti on, has been identi fi ed as the main detoxifi cati on strategy in wheat. In this work, we produced Triti cum durum cv. Svevo transgenic lines consti tuti vely expressing the barley HvUGT13248 gene. In them, DON-detoxifi cati on by UGT was found to confer a broad-spectrum resistance against F. graminearum and F. culmorum, aff ecti ng diff erent plant organs and developmental stages during FHB and FCR. When challenged with F. graminearum, the transgenic plants revealed a signifi cant reducti on (up to 30%) of FHB symptoms, mostly evident during early-mid stages of the infecti on progress. Notably, much higher DON-to-D3G conversion ability and considerable decrease of DON and DON+D3G content in wholemeal fl our of transgenic lines vs. nontransgenic control was observed. The higher effi ciency of D3G conversion since early infecti on stages may have reduced fungal progression and, consequently, DON and D3G contaminati on in kernels. Furthermore, we highlighted for the fi rst ti me the possible involvement of the DON-detoxifying mechanism in limiti ng FCR disease caused by F. culmorum. When challenged with the pathogen at the seedling stage, the HvUGT13248-expressing lines showed signifi cant reducti on (~50%) of FCR symptoms throughout the infecti on as compared to non-transgenic plants. Transgenic seedlings revealed also a bett er root tolerance to DON, which could have contributed to a higher seedling vigor during the infecti on. The concomitant effi cacy of the DON-detoxifi cati on strategy against FHB and FCR represents an att racti ng sustainable approach to pursue in breeding programs targeti ng broad-spectrum Fusarium resistance and hence reducti on of mycotoxin contaminati on of durum wheat-derived products
