A bestatin primes grapevine cells for augmented elicitation of the hypersensitive-like cell death and associated defense responses by methyl jasmonate

Localized treatment of grapevine (Vitis vinifera L. cv. Limberger) leaves with bestatin, an inhibitor of some aminopeptidases in plants and animals, augmented the sensitivity for methyl jasmonate-induced hypersensitive-like response. Enhanced resveratrol accumulation was associated with potentiated activation of genes encoding phenylalanine ammonia-lyase (PAL). The augmentation of PAL gene induction was proportional to the length of pretreatment with bestatin, indicating time-dependent printing of the cells. Exogenously supplied bestatin also potentiated other characteristic elicitor-induced short- and long-term defense responses in cell suspensions of grapevine including strong medium alkalinization and the production of reactive oxygen species (ROS), sequentially followed by defense gene activation and phytoalexin accumulation. Bestatin therefore appears to be exerting its effects close to the level of transcriptional control of defense-related genes, where it might inhibit a regulatory protease. Strikingly, the ability of bestatin to potentiate grapevine PAL gene elicitation and resveratrol accumulation, emphasizes an important role for defense response potentiation in acquired plant disease resistance.