Salicylic Acid Induced Insensitivity to Culture Filtrate of <i>Fusarium oxysporum</i> f.sp. <i>zingiberi</i> in the Calli of <i>Zingiber officinale</i> Roscoe
Salicylic acid (SA) was used to induce insensitivity in the callus cultures of Zingiber officinale against culture filtrate (CF) of Fusarium oxysporum f.sp. zingiberi . The treatment of callus cultures with SA (10 4 µM) prior to selection with CF of the pathogen-increased callus survival. Exogenous application of SA resulted in increased activity of peroxidase and ß-1,3-glucanase enzymes in the callus cultures. No increase in the activity of phenylalanine ammonia lyase was obtained. Two new protein bands of ~97 and 38kDa molecular weights were obtained by SDS-PAGE analysis of soluble proteins extracted from SA-treated calli. The PR-1 monoclonal antibody used for immunodetection of induced proteins cross-reacted with the 38kDa protein band. In vitro antifungal activity of protein extract of calli treated with SA tested against the spores of F. oxysporum f.sp. zingiberi showed significant reduction in spore germination and germ tube elongation. It is concluded that in ginger, SA may result in the induction of resistance to F. oxysporum f.sp. zingiberi by inducing increased activity of peroxidase, ß-1,3-glucanase and antifungal PR-proteins.