The Selection Of T-2Toxin-producing Fungal Strains And Their Affecting Factors

T-2toxin is the main inducement of Kashin-Beck Disease, is also the main fungal metabolite isolated from Kashin-Beck Disease areas. Took the wheat of Kaschin-Beck disease areas in Qinghai province as the research object, and separated different fungus from them, choosed58strains and did a research on their T-2toxin.Through the germ and yeast inhibit tests, initially screened the strains with high germ inhibition rate, such as14F1,5-5m-1, the total of17strains. The strains have the bacteriostatic effect such as the5-5m-1,3-5m-A,11F6, the total of7strains. Among them the5-5m-1both inhibit the growth and rebacteriostatic effect. The extract of the strains were purified with TLC and then identified them with HPLC, the results showed that the5-5m-1strain contains T-2toxin.Do the orthogonal experiment to the different extraction agents, and their different ratio, different extraction means and extraction time, the results showed that use extraction agents acetonitrile and water (84/16), ultrasonic extraction for45minutes can get best effect, but given its toxicity and price, the group merger isn’t the best choice. We can ultrasonic for60minutes and choose chloroform/ethanol (84/16)with low price and low toxicity.An investigation on different solid culture medium and liquid medium showed that training the5-5m-1with corn culture medium, under25℃, with half light illumination has a high field of T-2toxin, the best liquid culture is using potato liquid culture, half light illumination, pH5, but on the liquid medium, the toxin has little yield. So if we want to have a high toxin field, don’t choose the liquid medium to culture the strains.Train5-5m-1with corn culture medium for20days, and its T-2toxin field has reached the testing required level, the more important is that the culture medium is loose, less pigment, hyphae are not autolysised, these are helpful for the extraction of toxins, And chromatogram map has less noise peaks. Comprehensive consider the experiment efficiency, we choose20days as the best culture time.Through Morphological identification to the strains isolated from Kashin-Beck Disease families found that the advantage strain was Fusarium. The extract all of the strains were identified with HPLC, the result showed that except the5-5m-1, other strains5-5m-6,5F13,5F4,5-5m-7,5F10all can produce T-2toxin, accounting for27.27%of the total strains separated from Kashin-Beck disease families.