Methyl jasmonate triggers metabolic responses and gene expression on Vitis vinifera cultivar Loureiro infected with “flavescence dorée”

“Flavescence dorée” (FD) is a grapevine epidemic quarantine phytoplasma disease associated with high yield losses. This study aimed to evaluate the effect of methyl jasmonate (MeJA) on the induction of defence mechanisms of grapevines cultivar Loureiro against FD, comparing defence metabolites production (proline and saponins) and gene expression patterns in healthy and infected grapevine plants. The MeJA treatments significantly increased saponin and proline synthesis only in infected plants. Moreover, they induced gene expression of rubisco activase and pathogen-related proteins (PBSP, CHITC4c and PIN) quantified 6 hours after the MeJA application