Grapevine – Downy Mildew Rendez-Vous: Proteome Analysis of the First Hours of an Incompatible Interaction

Grapevine is one of the most relevant crops in the world being used for economically important products such as wine. Yet, relevant grapevine cultivars are heavily affected by diseases such as the downy mildew disease caused by Plasmopara viticola. Improvements on grapevine resistance are made mainly by breeding techniques where resistance traits are introgressed into cultivars with desired grape characteristics. However, there is still a lack of knowledge on how resistant or tolerant cultivars tackle the P. viticola pathogen. In this study, using a shotgun proteomics LC-MS/MS approach, we unravel the protein modulation of a highly tolerant grapevine cultivar, V. vinifera ‘Regent’, in the first hours post inoculation (hpi) with P. viticola. At 6 hpi, proteins related to defence and to response to stimuli are negatively modulated while at 12 hpi there is an accumulation of proteins belonging to both categories. The co-occurrence of effector-triggered susceptibility (ETS) and effector-triggered immunity (ETI) is detected at both time-points, showing that these defence processes present high plasticity. The results obtained in this study unravel the tolerant grapevine defence strategy towards P. viticola and may provide valuable insights on resistance associated candidates and mechanisms, which may play an important role in the definition of new strategies on breeding approaches.