Puccinia triticinaeffector Pt-1234 modulates wheat immunity by targeting transcription factor TaNAC069 via its C subdomain

The NAC (NAM, ATAF1/2, and CUC2) is a defense-associated transcription factor (TF) family that positively regulates defense responses to pathogen infection. TaNAC069positively regulates resistance in wheat to Puccinia triticina(Pt). However, the molecular mechanism of its interaction with a Pteffector is not clear. We found that Pteffector Pt-1234 interacts with TaNAC069 to subvert host immunity during Ptinfection. Quantitative real-time PCR analysis showed that expression of Pt-1234was significantly up-regulated during the early stage of Ptinfection. Protein-mediated cell death assays in wheat showed that the Pt-1234 protein was unable to induce cell death in wheat near-isogenic lines carrying different leaf rust resistance genes, whereas it suppressed BAX-induced cell death in leaves of Nicotiana benthamiana. Silencing of Pt-1234by host-induced gene silencing (HIGS) significantly reduced the virulence of Ptin the susceptible wheat variety Thatcher. The C subdomain of TaNAC069 was responsible for its interaction with Pt-1234, and the E subdomain was required for TaNAC069-mediated defense responses to Ptin planta. These findings indicate that Ptutilizes Pt-1234 to interact with wheat transcription factor TaNAC069 through its C subdomain, thereby modulating wheat immunity.