Effect of methyljasmonate and light on stilbene production in cell lines of Vitis vinifera and other Vitis species

Plants are constantly exposed to both biotic and abiotic environmental stress. Plant responses to these stresses involve different defense mechanisms, including the neo-synthesis of secondary metabolites, called fitoalexins (Chang et al. 2016). Among these, particular interest is addressed to the stilbenes, both for the biological role of chemical defense and for the numerous and well-proven biological activities on human health (Sirerol et al. 2015). Our study is focused on the biosynthesis of stilbenes, firstly resveratrol (the main exponent) and viniferins (resveratrol oligomers), in response to biotic stress in several species of the genus Vitis. In the plant, the accumulation of stilbenes is induced by the presence of phytopathogenic fungi (Langcake & Pryce 1976) or by abiotic stimuli as UV radiation (Roldan et al. 2003). Different stilbenes produced by grape show a synergistic activity, furthermore the quali-quantitative composition of the stilbenic content determines the resistance against specific pathogens. The species Vitis vinifera includes several cultivars quite different from the genetic point of view, since they are exclusively agamic propagated. Consequently, each of these show different levels of suscettibility to pathogens, such as Botrytis cinerea and Aspergillus spp., in relation to the different stilbene profile. Recently, great interest has also been paid for species of Vitis popularly known as “american grapes”, introduced in Europe as rootstocks due to their resistance against some important pathogens of V. vinifera. At present, resistance mechanisms of the american grapes are still unknown. The few avaiable data has been obtained from samples cultivated in field, where the conditions are not fully under control. The aim of the present research is to compare the stilbenic content of the cellular extracts in response to elicitation with methyljasmonate (MeJa), to identify and quantify the main stilbenes involved in resistance against phytopathogenic fungi. The role of light on stilbene production in the same cell cultures will also be investigated. Unespectedly, the obtained results indicate that cultivars of V. vinifera have a richer stilbenic content than the american grapes. For instance, V. vinifera cv. malvasia, in response to MeJa, increases the production of total stilbenes from 2.58 to 15.58 mg/g DW while Vitis rupestris cv. du Lot increases from 2.80 to 8.97 mg/g DW. Moreover, cell lines grown under light conditions accumulate higher levels of total stilbenes, both constitutively and in response to elicitation (e.g. malvasia: from 8.69 to 37.81 mg/g DW). Bibliography • Chang X. et al. (2012) PLoS One 7.7: e40446. • Langcake P. et al. (1976) Physiol Plant Path 9.1: 77-86. • Sirerol J. et al. (2015) Oxid Med Cell Longev 2016:3128951. • Roldán A. et al. (2003) J Agric Food Chem 51.5: 1464-1468