DETOXIFICATION OF ALPHA-TOMATINE BY FUSARIUM-SOLANI

The steroidal glycoalkaloid alpha-tomatine of tomato plants has been r eported to protect Lycopersicon species against fungal attack. Two iso lates from Fusarium solani were found to produce an extracellular enzy me inducible by alpha-tomatine. TLC showed that the enzyme catalyzes t he hydrolysis of the glycoalkaloid into beta-lycotetraose and tomatidi ne. The enzymatic activity was concentrated against polyethylene glyco l 35000, and the enzyme was partially purified by preparative isoelect ric focusing, preparative gel electrophoresis and ion-exchange chromat ography. The enzyme was found to be a monomer of about 32 kDa by both SDS-PAGE and gel filtration. This molecular mass differs from that of the tomatinase of Fusarium oxysporum (50 kDa). Moreover, polyclonal an tibody anti-tomatinase of F. oxysporum f. sp. lycopersici did not reco gnize the tomatinase from F. solani, suggesting that this tomatinase m ay be a novel enzyme.