ALLELIC VARIATION AT LOCI ENCODING DEHYDRINS IN WILD AND CULTIVATED BARLEY

¹ Department of Botany & Plant Sciences, University of California, Riverside, CA, USA

² Department of Agronomy, University of Bologna, Bologna, Italy

³ Institute of Plant Physiology, Genetics & Bioengineering, National Biotechnology Center, Ministry of Sciences and New Technologies of Kazakstan, Almaty, Kazakstan

⁴ Institute of Evolution, University of Haifa, Haifa, Israel

Dehydrins (DHNs; LEA D-11) are lipid-associating proteins involved in the adaptive response of plants to drought, low temperature and salinity. Little information has been available on the allelic variation of the genes encoding DHNs. We have sequenced a number of alleles of the major dehydration induced gene, Dhn4, from cultivated barley H. vulgare and its wild progenitor H. spontaneum. In a comparison of the region of Dhn4 containing the exons and a single intron, three major type of allelic variation are apparent, two at the protein level and one regarding the intron. At the protein level, there is a variable number of tandem phi segments between the K₁ and K₂ domains, ranging from six to nine in total. The other major variation at the protein level is a limited number amino acid substitutions, or small deletions or additions, at specific positions in the polypeptide sequence. There are two very different Dhn4 intron types, which would be consistent with some introgression of alien Dhn4 genes into the H. spontaneum gene pool. In total, 56 accessions of H. spontaneum representing a wide range of collection sites are included in this study. In H. vulgare, 30 cultivars representing the majority of barley cultivated in Europe and North America are included. Sequencing of the alleles of additional Dhn genes is presently underway.