Study on Optimum Conditions of Isolation and Purification of Specific Toxin Fractions Produced by Exserohilum turcicum / 微生物学通报

Five fractions,Ⅰ(R_f0.06)、Ⅱ(R_f0.21)、Ⅲ(R_f0.45)、Ⅳ(R_f0.60)、Ⅴ(R_f0.75)have been obtained after HT-toxin from race 1 of Exserohilum turcicum 99-2 isolated by TLC. In all of these fractions,only fractions Ⅱ had specific toxicity to the corn leaves with Ht1 gene. Then fractions Ⅱ-1、Ⅱ-2、Ⅱ-3 were isolated from fractions Ⅱ by HPLC purification,and the bioassay result showed only fraction Ⅱ-3 was toxigentic to corn leaves with Ht1 gene but non-toxigentic to corn leaves without Ht1 gene. Fractions Ⅱ-1、Ⅱ-2 and Ⅱ-3 were scanned by UV-Vis spectrophotometer. It was shown that the fractions Ⅱ-1 and Ⅱ-2 had analogous spectrum,and especially the fraction Ⅱ-3 had a special peak at 300nm.