Plant Genome IV Conference Plant Genome IV Conference
The genetic system that controls the response to environmental stress is characterized by the production of generic and specific stress proteins. The gene xfHvhsp17, isolated from Hordeum vulgare subjected to heat shock at 40 C for 2 hr, encodes for a cytoplasmic low molecular weight heat shock protein (class I). The expression of this gene was monitored in barley, maize and in transgenic tobacco in condition of heat and drought stress and reported specific induction by heat and a very limited effect in drought condition. Other genes, cloned from barley seedlings treated with ABA and encoding for proteins of the DHN or LEA type, but not only, showed a more specific expression in condition of drought stress. These genes have been mapped in several grasses and the map position utilized to establish the chromosomal localization of a drought related QTL. Stress inducible genes isolated in this way or by other molecular genetic techniques (RDD, RDA, subtractive hybridization, BSA) could be useful candidate genes in the dissection of these QTLs. Stress induced genes have been proved to be extremely powerful in an RFLP analysis in revealing the genetic distances between cultivars adapted to different ecogeographic conditions also characterized for the different water availability, and could be made interesting descriptors of what could be termed useful variation.