Transgenic expression of the TRI101 or PDR5 gene increases resistance of tobacco to the phytotoxic effects of the trichothecene 4,15-diacetoxyscirpenol

Mycotoxins are fungal secondary compounds that are toxic to vertebrates. Th eir presence in food and feeds, as the result of fungal disease in crops, c an present a danger to animal or human health. Many mycotoxins have also be en shown to be phytotoxic and in some cases, such as with trichothecenes pr oduced by the wheat head blight fungus Fusarium graminearum, mycotoxins may act as virulence factors. Antibiotic-producing organisms, including fungi, protect themselves from their own toxins by metabolic alteration of the co mpound, modification of the target site of action or by exporting the compo und to the extracellular space. We have tested the effectiveness of adaptin g two of these strategies, metabolic alteration and extracellular transport , to protect plant cells from the deleterious effects of the trichothecene 4,15-diacetoxyscirpenol (DAS). Tobacco plants were transformed with either the Saccharomyces cerevisiae gene PDR5, which encodes a multi-drug transpor ter, or with the Fusarium sporotrichioides gene TRI101, which encodes a tri chothecene 3-O-acetyltransferase. Both genes conferred significant increase d tolerance to DAS as measured by a sensitive seed germination assay. Expre ssion of PDR5 or TRI101 in a seed-specific manner in crop plants such as wh eat could lower the incidence of head blight as well as reduce mycotoxin le vels within the seed. (C) 2000 Elsevier Science Ireland Ltd. All rights res erved.