A constitutive cystatin-encoding gene from barley (Icy) responds differentially to abiotic stimuli

A barley cDNA clone encoding a cysteine proteinase inhibitor was characterized. The deduced amino acid sequence of this barley cystatin (Hv-CPI) contains the motif QXVXG conserved among members of the cystatin superfamily. The gene (Icy), located on chromosome 2, was expressed in embryos, developing endosperms, leaves and roots as assessed by northern blot analysis. Western blot analysis detected a slightly retarded band in leaves that was not present in roots or seeds. In these two organs a more precise location of Hv-CPI was done by immuno-histochemical analysis, with polyclonal antibodies raised against the recombinant CPI protein expressed in Escherichia coli. This protein efficiently inhibited papain (K _i 2.0×10^–8 M) and ficin (K _i 2.2×10^–8 M) and, to a lesser extent, chymopapain (K _i 1.6×10^–7 M) and was inactive against bromelain. The Icy mRNA expression in vegetative tissues increased in response to anaerobiosis, dark and cold shock (6 °C).these authors contributed equally to this work     

Homologous sucrose synthase genes in barley (Hordeum vulgare) are located in chromosomes 7H (syn. 1) and 2H. Evidence for a gene translocation?

The chromosomal location of the two types of sucrose synthase genes, Ss1 and Ss2, has been investigated in barley by Southern blot analysis of wheat-barley addition lines using non-cross-hybridizing-specific probes corresponding to the C-terminal regions of their respective cDNA clones (congruent to 250 bp). The Ss1 gene, whose cDNA of 2,667 bp has been entirely sequenced, is located in the beta-arm of chromosome 7H (syn. 1), while that corresponding to the homologous Ss2 is in the short arm of 2H, suggesting the existence of a translocation event between these two chromosomes in cultivated barley after an initial gene duplication and divergent evolution.     

Differential expression of two barley SNF1-related protein kinase genes

We have amplified and cloned DNA sequences derived from a gene encoding a SNF1 (sucrose-non-fermenting 1)-related protein kinase which differs from that previously reported from barley. Northern blot and polymerase chain reaction (PCR) analysis of RNA populations, using specific probes and oligonucleotide primers, indicated that the two SNF1-related genes are differentially regulated. One is expressed in all tissues, whereas the other is expressed at high levels in the seed endosperm and aleurone, but at levels undetectable by northern blot analysis in other tissues. Comparisons with other plant SNF1-related protein kinase genes suggest that the form which is expressed at greatly enhanced levels in the seed is less similar to the other plant homologues which have been reported and may be unique to cereals.