INDUCTION OF AN ACIDIC ISOZYME OF PEROXIDASE AND ACQUIRED-RESISTANCE TO WILT DISEASE IN RESPONSE TO TREATMENT OF TOMATO ROOTS WITH 2-FUROICACID, 4-HYDROXYBENZOIC HYDRAZIDE OR SALICYLIC HYDRAZIDE

Thirty nine derivatives of salicylic acid, nicotinic acid or furoic ac id were tested for their ability to induce cell wall bound peroxidase activity in an attempt to identify inducers of acquired resistance. Th e activity of cell wall bound peroxidase in tomato hypocotyls was enha nced by treatment of roots with 4-hydroxybenzoic hydrazide (4HBHZ), sa licylic hydrazide (SHZ), or 2-furoic acid (2FA). Isoelectric focusing revealed that an acidic isozyme (pI 4.6) of peroxidase was induced spe cifically by treatment with these compounds. The isozyme was induced i ndependently to wounding or pathogen infection. Dipping roots in solut ions of these compounds at concentrations of 0.1 mu m 4HBHZ, 1.0 mu m SHZ and 10 mu m 2FA also induced resistance against the tomato wilt di sease caused by Fusarium oxysporum f.sp. lycopersici. (C) 1998 Academi c Press Limited.