Abstract
Among the plant-specific transcription factors, ethylene response factors (ERFs) conform one of the largest gene families in several plant species. ERFs are considered to have critical roles in the responses to the various environmental stresses and pathogens. So far, we revealed that the gene expression of a tobacco transcriptional repressor NtERF3 was up-regulated during the hypersensitive response (HR) induced by tobacco mosaic virus (TMV) infection in tobacco plants harboring the resistance gene N to TMV, and that transient overexpression of NtERF3 by the Agrobacterium-infiltration method induced HR-like cell death in tobacco. NtERF3 has an EAR repression motif in its C-terminal region. The cDNAs for some EAR-motif-containing ERFs were isolated from Arabidopsis, rice and tobacco, and many of the isolated genes induced HR-like cell death when overexpressed in tobacco. These results suggested that multiple ERF genes, which belonged to the same subgroup as NtERF3, might be involved in HR or cell death induction. Now, we are analyzing the effect of NtERF3 on TMV resistance by using the transgenic tobacco expressing a dominant negative type of NtERF3.
