Effects of Ethylene Inhibitors on the Long-Term Maintenance of the Embryogenic Callus of Vitis vinifera L.

Abstract

Vitis vinifera is an important fruit crop which is mainly consumed fresh or used for the production of wine. Genetic improvement programs through New Genomic Techniques (NGTs) aim to develop grapevine varieties resistant to biotic and abiotic stresses or enhancing nutraceutical properties. In order to apply NGTs, maintaining embryogenic calluses from flower tissues is critical. Optimizing culture conditions—pH, gelling agents, temperature, light, growth regulators, and gas composition—is essential for inducing efficient embryogenic responses tailored to each genotype/explant. Ethylene, a pivotal gaseous plant hormone, significantly influences tissue culture by affecting organogenesis and embryogenesis processes in several plants. Modulating ethylene levels shows promise for improving tissue culture vitality. This study evaluates in Vitis vinifera the effects of silver thiosulfate (STS) and salicylic acid (SA) on embryogenic callus growth, specifically investigating their roles in maintaining and inducing embryogenic competence. STS, particularly at 40 µM and 60 µM concentrations, effectively preserved embryogenic competence in Italia and Red Globe calluses, while high SA concentrations showed varied and occasionally adverse effects. At the same time, STS markedly suppressed the non-embryogenic callus growth in recalcitrant variety Italia, potentially increasing the ratio between embryogenic to non-embryogenic calluses development.