Durum wheat genes up-regulated in the early phases of cold stress are modulated by drought in a developmental and genotype dependent manner

A set of 10 durum wheat genes isolated as early induced in response to cold and light and 10 Cbf genes were tested for their expression in a range of durum wheat samples obtained from plants at different stages of development and exposed to different dehydration conditions. All tested genes showed some transcript accumulation also in response to water stress, indicating that each of them represents a target of the cold and dehydration signalling pathways. Gene expression profiles changed in response to water stress treatment in a way strictly dependent on developmental phase, tissue analysed and stress protocol applied. Significant differences were observed in dehydration-dependent transcript accumulation when durum wheat varieties, chosen on the basis of their tolerance to water stress, were analysed. Genes clearly up-regulated by water stress in some genotypes, but down-regulated in others were also found. Among the cultivars tested the most tolerant variety, Ofanto, showed the highest number of up-regulated genes. These findings also point out that a general frame of the molecular response to water stress cannot be drown from the analysis of few experiments, rather the plant molecular response to dehydration changes continuously resulting from an integration of a series of internal and external stimuli.