The presence and phytotoxicity of fumonisins and AAL-toxin in Alternaria alternata.

The fumonisins (FB) and AAL-toxin are known to be produced by Fusarium moniliforme and Alternaria alternata f. sp. lycopersici when grown on rice. Alternaria alternata produced 1.3-3.1 ppm FB1 when grown on PDA for 2 weeks at 26 degrees C as determined by CD-ELISA and 0.6 ppm as determined by CF/FAB/MS. ELISA consistently yielded higher results than CF/FAB/MS. The presence of FB2, FB3 and AAL-toxin were demonstrated in spores and mycelia of A. alternata by CF/FAB/MS. The presence of AAL-toxin was further confirmed by demonstration of increased free sphingoid bases in tomato plants exposed to fungal spores and mycelia. This is the first report of AAL-toxin, FB2 and FB3 in spores and mycelia and confirms the presence of FB1 in A. alternata.