Identifcation and characterization of a seed-specifc grapevine dehydrin involved inabiotic stress response within tolerant varieties

Abstract

To identify and isolate genes related to abiotic stress (salinity and drought) tolerance in grapevine, a candidate gene approachled to the isolation from Cabernet Sauvignon cultivar of a full-length cDNA of dehydrin gene. Te latter, named VvDhn , which is highlyand mainly induced in late embryogenesis in seeds, encodes for a protein of 124 amino acids with a predicted molecular mass of 13.3kDa. Details of the physicochemical parameters and structural properties (molecular mass, secondary structure, conserved domainsand motives, and putative posttranslational modifcation sites) of the encoded protein have also been elucidated. Te expression study ofVvDhn was carried out within plant organs and tissues as well as under drought and salt stresses. VvDhn was not detected in vegetativetissue, whereas it was only expressed during seed development (during late embryogenesis) at extremely high levels and was induced bysalt and drought stresses as well as ABA application. Moreover, salt stress induced VvDhn expression in the tolerant variety (Razegui)but not the sensitive variety (Syrah), which did not display expression variation during stress; VvDhn expression level and salt-stressresponse depend on regulatory mechanisms that are efcient only in the tolerant variety. On the other hand, under drought stressVvDhn was induced in both tolerant and sensitive varieties, with higher levels in the tolerant variety. In addition, stress signal moleculessuch as ABA (applied alone or in combination with saccharose) induced VvDhn expression, even at low levels. Minimal knowledgeabout the role and functionality of this gene is necessary and constitutes a prerequisite for including VvDhn in grapevine abiotic stresstolerance improvement programs.