Proteome responses of Grapevine to Downy mildew

A comparative proteomic analysis of grapevine leaves from the resistant genotype V. davidii ‘LiuBa-8’ (LB) and susceptible genotype V. vinifera ‘Pinot Noir’ (PN) at 12 hpi was conducted to understand the complex relationship between grapevine and P. viticola and the molecular mechanisms between difference resistant vitis genotypes at the early stage of infection. A total of 444 and 349 differentially expressed proteins (DEPs) were identified in LB and PN respectively at 12 hpi by iTRAQ. MapMan analysis showed that the majority of these DEPs were related to photosynthesis, metabolism, stress and redox. More up-expressed DEPs involved in photosynthesis and less down-expressed DEPs involved in metabolism contribute to the resistance in LB. PR10.2, PR10.3, HSF70.2 and HSP90.6 are proposed to be key proteins in both compatible and incompatible interactions. Accumulation H2O2 established the ROS signaling in incompatible interaction and APXs, GSTs maybe associated with the resistance of grapevine against downy mildew. Moreover, we verified four proteins to ensure the accuracy of proteome data using PRM. Overall, these data provide new insights into molecular events and provide valuable candidate proteins that could be used to illuminate molecular mechanisms underlying the incompatible and compatible interaction in early stage and eventually to be exploited to develop new protection strategy against downy mildew in grapevine.