Characteritics Of HSF Genes And HSP70 Genes In Zea Mays

As the important member of heat shock or other signal transduction pathway, heat shock transcription factor (HSF) directly activates the gene expression of the downstream heat shock proteins (HSPs). HSF plays an important role in both regulation of HSP gene expression and the transmission of stresses and the improvement of plant stress tolerance, especially during heat shock stress. In this paper, the characteristics of HSF genes and HSP70 genes and their possible functions were studied through Zea mays seedlings. Both HSF and HSP70 genes were cloned by RT-PCR and heat shock-related genes were screened by the semi-quantitative RT-PCR. We also researched the expression of those genes under the stresses of cold,salt,drought and ABA respectively. The following results were showed:Using the method of RT-PCR, we obtained three HSF genes from leaves of Zea mays seedlings, and one HSF gene was significantly induced by heat stress. The ORF of the HSF gene is 1404bp, encoding 463 amino acids. The HSF gene was named ZmHSF. Semi-quantitative RT-PCR results showed that both heat, cold, salt, drought stresses and exogenous ABA could induce the gene expression significantly, providing a new basis for the theory of cross adaptation of plant to environmental stresses.In order to study the interaction between HSFs and HSP70s, we obtained three HSP70s genes from Zea mays leaves, one of them was induced significantly by heat shock. The ORF of the HSP70 gene was 1737 bp, encoding 578 amino acids. The gene was named ZmHSP70. The comparison of the deduced amino acid sequences of the ZmHSP70 with SbHSP70 (XP₀02465635) and OsHSP70 (EAY89062) showed that this was a highly conserved protein and the identity was 95%, 87%, respectively. Semi-quantitative RT-PCR results showed that both heat shock at 42℃and cold stress at 4℃increased the expression of ZmHSP70 gene.