Abstract
Grapevine is one of the most important fruit crops in the world, which is severely threatened by drought. Therefore, understanding grapevine drought response mechanisms is needed to develop grapevine cultivars that can tolerate this stress. In the present report, a comparative proteomic study using 2D-PAGE was performed on two wild grapevine accessions, Tebaba (salt tolerant) and Houamdia (salt sensitive), to identify proteins that play key roles in drought responsive mechanisms. Plants were exposed to water deficit stress for 16 days. Physiological observations did not indicate any difference in drought tolerance between the two accessions. However, the comparative proteomic study showed that 18 drought-responsive proteins changed in both accessions under drought stress and 48 (29 in Houamdia and 19 in Tebaba) were variety specific. Based on changes in protein abundance induced by drought stress, carbohydrate and energy metabolism were similarly up-regulated in both accessions. Amino acid metabolism was more negatively affected by the stress in Houamdia accession. Interestingly, the three ROS scavenging proteins APX, ASR2 and GRXS17 were up-regulated only in Tebaba. Some drought-responsive proteins, such as RBP, RuBisCO, RCA, 26S protease, CLpA and 14–3-3-like protein were up-regulated by the stress in Tebaba, whereas they were down-regulated in Houamdia. Taken together, these results suggest that Tebaba may alleviate drought stress through an activation of photosynthesis and redox reactions, and a degradation of misfolded/damaged proteins. Information given in this report could be helpful for selecting candidate proteins/genes as markers in improving drought tolerance in grapevine cultivars.