The effect of heat stress and cadmium ions on the expression of a small hsp gene in barley and maize

Small heat shock proteins in plants are produced under stress conditions and play an important role in stress tolerance. The gene Hvhsp17 isolated from barley encodes a class I, low molecular weight heat shock protein (or sHSP) which is induced in barley seedlings in response to heat stress. Previous molecular analysis of the 5′ promoter region of Hvhsp17 uncovered several cis regulatory elements upstream from the ATG of the gene, two heat shock elements (HSE1 and HSE2), and a sequence highly homologous to a metal responsive element of mammalian cells. The importance of the protective role of these elements against abiotic stresses was investigated both in barley and in maize. The expression profile of Hvhsp17 in response to various environmental conditions was analysed in these two cereals, to understand the regulation of Hvhsp17 gene expression and also in relation to conditions other than heat shock. The expression of Hvhsp17 in both barley and maize is strictly associated with heat stress, except for treatment with cadmium ions.