A NAC Transcription Factor TuNAC69 Contributes to ANK-NLR-WRKY NLR-Mediated Stripe Rust Resistance in the Diploid Wheat Triticum urartu

Abstract

Stripe rust is one of the most devastating diseases in wheat. Nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domain receptors (NLRs) recognize pathogenic effectors and trigger plant immunity. We previously identified a unique NLR protein YrU1 in the diploid wheat <i>Triticum urartu</i>, which contains an N-terminal ANK domain and a C-terminal WRKY domain and confers disease resistance to stripe rust fungus <i>Puccinia</i>&nbsp;<i>striiformis</i> f. sp. <i>Tritici</i> (<i>Pst</i>). However, how YrU1 functions in disease resistance is not clear. In this study, through the RNA-seq analysis, we found that the expression of a NAC member <i>TuNAC69</i> was significantly up-regulated after inoculation with <i>Pst</i> in the presence of YrU1. TuNAC69 was mainly localized in the nucleus and showed transcriptional activation in yeast. Knockdown <i>TuNAC69</i> in diploid wheat <i>Triticum urartu</i> PI428309 that contains YrU1 by virus-induced gene silencing reduced the resistance to stripe rust. In addition, overexpression of <i>TuNAC69</i> in <i>Arabidopsis</i> enhanced the resistance to powdery mildew <i>Golovinomyces cichoracearum</i>. In summary, our study indicates that TuNAC69 participates in the immune response mediated by NLR protein YrU1, and likely plays an important role in disease resistance to other pathogens.