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Abstract: Salt stress adversely affects the growth of grapevine plants. In order to understand the molecular basis of salt stress response in grapevine plants, suppression subtractive hybridization (SSH) and microarray based screening approaches were combined. Two leaf-specific subtractive cDNA libraries were constructed from grapevine plants subjected to a moderate, incremental salt stress treatment. SSH were performed 6h and 24h after NaCl peaked at 100mM using cDNAs prepared from leaves of a salt tolerant cultivar (Razegui) as testers and cDNAs from unstressed leaves as drivers. Then, a pre-screened subset of cDNA clones from these SSH libraries were used to construct a Vitis vinifera cDNA array, in order to verify the expression changes of the genes upon salt treatment. Expression profiles were compared between the salt tolerant and a susceptible cultivar (Syrah) under both control conditions and after salt stress treatment. Seven cDNA clones were identified which were up-regulated by salt stress in two independent growth experiments and confirmed by RNA blot analysis. The transcript expression patterns of the selected genes differed between the contrasting grapevine cultivars tested with respect to stress-regulation. The possible relationship of individual cDNAs with salinity tolerance mechanisms is discussed. [Copyright &y& Elsevier]

Summary: Salt stress is one of the major abiotic stresses in agriculture worldwide, especially in the Mediterranean area. We report here a proteomic approach to investigate the salt stress-responsive proteins in grapevine (Vitis vinifera). Two-dimensional electrophoresis (2-DE) was used to analyze the proteome of the salt-tolerant Tunisian grapevine cultivar Razegui, subjected to a supply of 100mm NaCl over 15d. Analysis of 2-DE gels derived from stressed plants revealed more than 800 reproducibly detected protein spots, with 48 proteins displaying a differential expression pattern, including 32 up-regulated, 9 down-regulated and 7 new protein spots induced after salt treatment. The presence of stress-responsive proteins in the different plant organs suggests that salt spreads systemically. Edman degradation analysis and database searching aided us in identifying a major protein GP. Database analysis revealed that this peptide has a 98% sequence similarity with a pathogenesis-related (PR) protein 10 (V. vinifera). A full-length cDNA encoding the GP protein was isolated from grapevine salt-stressed leaves and sequenced. The predicted protein contained 158 amino acids and showed 98% identity with PR10 protein of of V. vinifera (accession no. Cac16165). [Copyright &y& Elsevier]