Response of the Vitis vinifera L. cv. 'Nebbiolo' proteome to Flavescence doree phytoplasma infection

Flavescence doree is a serious phytoplasma disease affecting grapevine in several European countries. We studied the interaction of Flavescence doree phytoplasma with its natural plant host by monitoring the effects of infection on the protein expression profile. Among the 576 analyzed spots, 33 proteins were differentially regulated in infected grapevines. Grouping into MIPS functional categories showed proteins involved in metabolism (21%), energy processes (9%), protein synthesis (3%), protein fate (18%), cellular transport and transport routes (6%), cell defense and virulence (42%). Among the differentially regulated proteins, we selected six targets (thaumatin I, thaumatin II, osmotin-like protein, plant basic secretory protein, AAA 1 Rubisco activase and proteasome alpha 5 subunit) and we analyzed their expression by quantitative RT-PCR on samples collected in 2008 and 2009 in several vineyards in Piedmont region, Italy. There was a positive correlation between mRNA and protein expression for most of the genes in both the years. We discuss the involvement of these proteins in the specific response to phytoplasma infection. To our knowledge, this work is the first to investigate the response of the grapevine proteome to Flavescence doree phytoplasma infection, and provides reference protein profiles for future comparative proteomic and genomic studies.