Two cold - inducible genes encoding li barley

The barley genes HvLtp4.2 and HvLtp4.3 both encode the lipid transfer protein LTP4 and are less than 1 kb apart in tail-to-tail orientation. They differ in their non-coding regions from each other and from the gene corresponding to a previously reported Ltp4 cDNA (now Ltp4.1). Southern blot analysis indicated the existence of three or more Ltp4 genes per haploid genome and showed considerable polymorphism among barley cultivars. We have investigated the transient expression of genes HvLtp4.2 and HvLtp4.3 folio wing transformation by particle bombardment, using promoter fusions to the j9-glucuronidase repórter sequence. In leaves, activities of the two promoters were of the same order as those of the sucrose synthase (Ssl) and cauliflower mosaic virus 35S promoters used as controls. Their expression patterns were similar, except that Ltp4.2 was more active than Ltp4.3 in endosperm, and Ltp4.3 was active in roots, while Ltp4.2 was not. The promoters of both genes were induced by low temperature, both in winter and spring barley cultivars. Northern blot analysis, using the Zíp4-specific probé, indicated that Xanthomonas campestris pv. translucens induced an increase over basal levéis of Ltp4 mRNA, while Pseudomonas syringae pv. japónica caused a decrease. The Ltp4.3-Gus promoter fusión also responded in opposite ways to these two compatible bacterial pathogens, whereas the Ltp4.2-Gus construction did not respond to infection.