A newly identified barley gene, Dhn12 encoding a YSK2 DHN, is located on chromosome 6H and has embryo-specific expression

Dehydrins are water-soluble lipid-associating proteins that accumulate duri ng low-temperature or water-deficit conditions, and are thought to play a r ole in freezing- and drought-tolerance in plants. Dhn genes exist as multi- gene families in plants. Previously, we screened lambda genomic libraries o f two barley cultivars in an effort to isolate all of the barley Dhn genes. We identified 11 unique Dhn genes and estimated a total of 13 Dhn genes in the barley genome. To extend the collection, we used an alternative source of clones, a I.5xMorex barley BAC library. In this library, we found nine Dhn genes that we described previously and one new Dhn gene, Dhn12. The Dhn 12 gene encodes an acidic YSK2 dehydrin. The Dhn12 gene is located on chrom osome 6H, and shows a different expression pattern from all other Dhn genes identified previously. RT-PCR results show that Dhn12 expression is embryo -specific. Dhn12 is not expressed in seedling shoots under any of the condi tions tested, including non-stressed as well as dehydrated, or cold-, ABA- or NaCl-treated seedlings.