The Cloning of cDNAs for the Heat-shock Transcription Factors HSFA1, HSFA2 and HSFA3 from Tobacco

抄録

In view of the progression of global warming, the molecular breeding of crops, tolerant to high temperatures is an urgent concern for agricultural practices in the future, particularly in the tropical and sub-tropical areas. This makes it necessary to elucidate the molecular mechanism of heat-shock response (HSR) in plants. It has been demonstlated that heat-shock factors (HSFs) play central roles in regulating most of the genes involved in HSR, including those for heat-shock proteins (HSPs). Among the HSFs, HSFA1 is an essential factor involved in HSR, while HSFA2 and HSFA3 directly induce the expression of genes essential for overcoming high-temperature stress (HS). In this study, we cloned the HsfA1, HsfA2 and HsfA3 cDNAs from tobacco, which were designated as NtHsfA1, NtHsfA2 and NtHsfA3, respectively. Sequence analyses of the cDNAs revealed that they were partial cDNAs. Phylogenetic analysis confirmed that they could be classified into three groups, namely, HsfA1, HsfA2 and HsfA3. A comparison of tobacco HsfA1 with its homologous genes suggested that this gene group is more diverse than the groups of HsfA2 and HsfA3.