Exogenous application of a lipid transfer protein-jasmonic acid complex induces protection of grapevine towards infection by Botrytis cinerea

Type I plant lipid transfer proteins (LTPs) are small, basic, cystein-rich proteins involved in plant defense mechanisms. Five type I LTPs isoforms, named VvLTP1, 2, 3, 4 and 5 (Vitis vinifera lipid transfer proteins 1–5) were purified to homogeneity from the culture media of 41B grapevine cell suspension. The full sequence of isoforms 1, 3, 4 and 5 could be determined from mass spectrometry measurements of the enzymatically hydrolyzed proteins and from available VvLTP sequences. Phylogenetic analysis revealed that these proteins form two subgroups, one with isoforms 1 and 4, and the second one with isoforms 3 and 5. The ability of the three most abundant ones (VvLTP1, 4 and 3) to interact with jasmonic acid (JA) was tested by fluorometric studies, showing that VvLTP4 was the most efficient to interact with this oxylipin. Exogenous application of the VvLTP4-JA complex on grapevine plantlets induced a high level (80.3 ± 10.05%) of tolerance towards Botrytis cinerea, as compared with control plants (18.65 ± 12.13%); whereas plants treated with JA or VvLTP4 alone exhibited a lower protection level (31.04 ± 9.72% and 45.52 ± 7.51% of protection, respectively). The results are discussed in the context of grapevine defense mechanisms.