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

Abstract

The NAC (NAM, ATAF1/2, and CUC2) is a defense-associated transcription factor (TF) family that positively regulates defense responses to pathogen infection. positively regulates resistance in wheat to (). However, the molecular mechanism of its interaction with a effector is not clear. We found that effector Pt-1234 interacts with TaNAC069 to subvert host immunity during infection. Quantitative real-time PCR analysis showed that expression of was significantly up-regulated during the early stage of infection. 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 . Silencing of by host-induced gene silencing (HIGS) significantly reduced the virulence of in 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 in planta. These findings indicate that utilizes Pt-1234 to interact with wheat transcription factor TaNAC069 through its C subdomain, thereby modulating wheat immunity.