Comparative analysis of genomic sequence and expression of a lipid transfer protein gene family in winter barley

Three genomic clones (gb/*4.2, gb/f4.6, gb/t4.9) have been isolatedfrom a barley [Hordeum vulgare L.) cv. Igri genomic libraryusing a cDNA clone of the low temperature responsive gene b/r4.1as the probe. The genomic clones are closely related and fromsequence homology are believed to be three further members ofa barley gene family encoding lipid transfer proteins. One clone,gb/t4.9, corresponds to a second cDNA clone (Jb/f4.9). Northernblot analysis revealed that the three genes reported here areinduced by low temperature and drought; however, the relativelevel of response to these stimuli was shown to differ betweenthe genes. Further, the developmental response of gb/?4.2 isdifferent from that found for other members of the gene family.The degree of low temperature induction of the blt4 gene familyappears to be cultivar-dependent. Comparative analysis of the putative promoter regions of thegenomic clones indicates three regions that show over 80 sequenceconservation between gb/f4.9 and gb/f4.6. Also identified areputative cis acting elements previously identified in ABA responsivegenes and low temperature inducible genes. The possible functionalsignificance of the conserved regions and elements is discussedin relation to the expression of the blt4 gene family. Key words: Barley, gene expression, genomic sequence, lipid transfer protein, low temperature