Metabolism of Trichothecenes by Wheat

Feeding experiments were conducted to determine whether wheat could metabolize exogenously added trichothecenes. Middle spikelets of a moderately resistant wheat cultivar Su8060 were fed in triplicate, on ten sets of plants, with a fixed amount of deoxynivalenol (DON, 4000 ng). One day after adding DON, the treated spike on one set of plants and adjacent tissue was removed for toxin analysis using GC-MS. The remaining nine sets of plants were fed with DON again. This daily process of toxin addition and sampling was continued until all spikes were harvested for toxin analysis. The same procedure was carried out with 15acetyldeoxynivalenol (15ADON, 1000ng), 3-acetyldeoxynivalenol (3ADON, 500ng) or a combination of the three toxins (4000ng of DON, 1000ng of 15ADON and 500ng of 3ADON). The results showed that, when fed DON alone, DON was found in both the fed spikelets and adjacent fragments of rachis. Additionally in DON treatments, both 15ADON and 3ADON were recovered but only from the fed spikelets. When fed with 15ADON, both DON and 15ADON were recovered from both the fed spikelets and adjacent fragment of rachis. When fed with 3ADON, both DON and 3ADON were detected only in the fed spikelets. In all cases, change in the amount of toxins followed the same pattern: reaching the highest cumulative level on the fifth or sixth day of the experiment, and then decreasing to a lower level on the seventh or eighth day despite continued toxin addition. Toxin levels increased from the ninth day until end of this experiment. When fed with the combination of DON, 15ADON and 3ADON in the ratio of 8:2:1, the relative amounts of the three toxins recovered from the fed spikelets varied significantly, from 24:3:1 to 80:7:1. Nivalenol was not detected in any treatment. We hypothesize that the resistant wheat plant metabolizes trichothecenes into different forms as well as other uncharacterized metabolic products. (This study is supported by National Natural Science Foundation of China, 30170601and 39870471) 2002 National Fusarium Head Blight Forum Proceedings 190 Food Safety, Toxicologgy and Utilization YEAST STRAINS ALLOWING PHENOTYPIC DETECTION OF ESTROGENIC ACTIVITY: DEVELOPMENT OF A SENSITIVE AND INEXPENSIVE YEAST BIOASSAY FOR ZEARALENONE R. Mitterbauer1, H. Weindorfer1, N. Safaie2, H. Bachmann1 and G. Adam1* 1Center of Applied Genetics, University of Agricultural Sciences, Vienna, Austria; and 2Tarbiat Modarres University, Tehran, Islamic Republic of Iran *Corresponding Author: PH: 43-1-36006-6380; E-mail: [email protected]