Selective toxins and analogs produced by Helminthosporium sacchari. Production, characterization and biological activity.
H. [Drechslera] sacchari toxin and several lower mol. wt. nontoxic analogues were isolated from culture filtrates. Three isomers of the toxin (A, B and C), each with 4 galactose units, were separated by HPLC. C had the highest and A the lowest toxicity to D. sacchari-susceptible sugarcane; resistant clones were not affected. Biochemical studies indicated that the sesquiterpene isomer, the number of galactose units and the galactose arrangement pattern determine the effectiveness of the compound in inducing electrolyte loss and in preventing toxin-induced loss from sugarcane tissues.