New findings to the role of tunikamycin in grapevine: Disease defense responses

Abstract

Exogenous methyl jasmonate (MeJA) is an effective trigger of cellular damage resulting in the development of limited necrotic lesions that mimic the hypersensitive reaction (HR) lesions associated with resistance to avirulent pathogens. Localized treatment of leaves of intact grapevines (Vitis vinifera L. cv. Limberger) or excised leaves with tunikamycin stimulates an agonist-dependent mechanism operating at an early step in the signal pathway for induction of MeJA-dependent UR-like response. With respect to tunikamycin, the fine control mechanism has shown to be both, concentration- and time-dependent. The same treatment also antagonized H₂O₂ accumulation from the MeJA-induced oxidative burst suggesting that this type of reactive oxygen intermediate plays a minor role in the induction of the HR in grapevine cells challenged by exogenous MeJA. Moreover, our results indicate that the activation of defense reactions of grapevine, at least in part, is dependent and sensitive to N-linked glycosylation.