Nonspecific Lipid-Transfer Protein Genes Expression in Grape (Vitissp.) Cells in Response to Fungal Elicitor Treatments

Nonspecific lipid transfer proteins (nsLTPs) are small, basic cystein-rich proteins believed to be involved in plant defense mechanisms. Three cDNAs coding nsLTPs from grape (Vitis vinifera sp.) were cloned by reverse-transcriptase-polymerase chain reaction (RT-PCR) and PCR. The expression of nsLTP genes was investigated in 41B-rootstock grape cell suspension, in response to various defense-related signal molecules. Ergosterol (a fungi-specific sterol) and a proteinaceous elicitor purified from Botrytis cinerea strongly and rapidly induced the accumulation of nsLTP mRNAs. Jasmonic acid, cholesterol, and sitosterol also promoted nsLTPs mRNA accumulation, although to a lesser extent, whereas salicylic acid had no effect. High performance liquid chromatography analysis indicated that the amounts of three LTP isoforms (previously named P1, P2, and P4) were increased by ergosterol. None of the four isoforms displayed any significant antifungal properties, with the exception of the P4 isoform, which reduced Botrytis mycelium growth in vitro, but only in calcium-free medium. The results are discussed in the context of plant-pathogen interactions.