RESUMO
The use of methyl jasmonate, alone or in combination with cyclic oligosaccharides such as cyclodextrins, has proved to be a successful strategy for increasing the production of trans-resveratrol in Vitis vinifera cell cultures. However, understanding the intracellular signalling pathways involved in its production would improve the management of grapevine cells as biofactories of this high-value natural product. The results obtained herein confirm the involvement of hydrogen peroxide and nitric oxide in cyclodextrins and methyl jasmonate-induced trans-resveratrol production in grapevine cell cultures. In fact, methyl jasmonate led to maximal intracellular levels of hydrogen peroxide and nitric oxide after 24 h of treatment, but extracellular hydrogen peroxide was only detected in the culture medium when grapevine cells were treated with cyclodextrins. The results derived from the cytochemical detection of H2O2 in elicited grapevine cell cultures also suggested that the combined treatment with cyclodextrins and methyl jasmonate not only increased the production of H2O2 but also released cell wall fragments with electron-dense deposits. Moreover, nitric oxide was localized in all the cellular compartments, particularly in the nucleus and cytoplasmic organelles, whereas hydrogen peroxide was mainly found in cytoplasmic areas close to the cell wall, and in the nucleoplasm.
