Abstract: Wheat sharp eyespot, mainly caused by Rhizoctonia cerealis, and Fusarium head blight (FHB), primarily caused by Fusarium graminearum, are important diseases of wheat (Triticum aestivum L.) in China. We have isolated a pathogen-induced ERF gene from wheat, TaPIEP1, which encodes the ERF transcription factor TaPIEP1. TaPIEP1 localizes to the nucleus, binds to the GCC-box cis-element and possesses the transcriptional-activation activity. To study the roles of TaPIEP1 in wheat defense responses to the major pathogens of sharp eyespot and FHB, we characterized the TaPIEP1 transgenic wheat plants in T₄ and T₅ generations by PCR, Southern blot, RT-PCR, and Q-RT-PCR analyses. We also evaluated the disease resistance in these TaPIEP1 transgenic plants through inoculating R. cerealis and F. graminearum. The PCR and Southern blotting results showed that the alien TaPIEP1 was inherited stably in transgenic wheat plants, and was independently integrated with a single copy or two copies into seven transgenic wheat lines, suggesting that these transgenic wheat lines derived from seven transformants. The RT-PCR and Q-RT-PCR analysis results indicated that the alien gene TaPIEP1 was over-expressed in eight transgenic wheat lines. Compared with untransformed wheat host Yangmai 12, the eight transgenic wheat lines over-expressing TaPIEP1 showed significantly-enhanced resistance to R. cerealis infection. Out of them, some plants of three transgenic wheat lines displayed improved-resistance to both R. cerealis and F. graminearum infections. These results suggest that TaPIEP1 gene is involved in defense responses to attack with R. cerealis and F. graminearum, and TaPIEP1 is useful for improving wheat resistance to both diseases.

Key words: Wheat, ERF transcription factor, Transgene, Sharp Eyespot, Fusarium head blight, Resistance