Prunus persica apoplastic proteome analysis reveals candidate proteins involved in the resistance and defense against Taphrina deformans

Abstract The first Prunus persica apoplastic proteome analysis was assessed by LC-MS/MS. 365 proteins were identified and molecular/biological function classified. Taphrina deformans in the pathogenic fungus responsible for the leaf peach curl disease. To gain insight into the molecular mechanisms involved in plant resistance and response to the fungus, apoplastic differentially abundant proteins (DAPs) in a resistant (DR) and/or in a susceptible genotype (FL) were identified after 12 and 96 hours post inoculation (hpi) and compared to those at 0 hpi. In both genotypes, major changes occurred at 96 hpi when the fungus had achieved the filamentous form. However, at 96 hpi, DR exhibited a greater number of increased proteins than FL. DAPs were enriched in biotic stress response, with most of the proteins belonging to the pathogenesis related (PR)-type. PRs exhibited the greatest fold changes of induction in DR. While PRs acting on pathogen cell wall (PR2, PR3 and PR4) were increased in both susceptible and resistant genotypes, others were exclusively induced in DR as PR5, defensin and PR17. Proteins exclusively induced in DR upon T. deformans inoculation such as a dirigent protein, three berberine bridge enzymes, a glyoxal oxidase-related, two snakins and a GDS-lipase were identified. Moreover, upon inoculation cuticle was thickened to a greater extent in DR than in FL. This work reveals the active role of the apoplast against T. deformans and not only contributes to the elucidation of the responses involved in resistance to leaf curl disease but also improves knowledge on peach defenses against pathogens.