TuNHL1, an NDR1/HIN1 like gene, is essential for YrU1-mediated stripe rust resistance and enhances powdery mildew resistance in plants.

Abstract

YrU1 encodes a coiled-coil nucleotide-binding site leucine-rich repeat (CNL) immune receptor with additional ankyrin-repeat and WRKY domains, and confers robust resistance against the stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst). YrU1 was identified through map-based cloning in Triticum urartu accession PI428309, the progenitor species of the A genome of hexaploid wheat. Despite its established role in conferring Pst resistance, the molecular mechanisms and interacting components involved in YrU1-mediated immunity remain largely undefined. In this study, we identified TuNHL1, a plasma membrane-localized NDR1/HIN1-like (NHL) protein, as a key component required for YrU1-mediated stripe rust resistance. TuNHL1 exhibits self-association and is capable of triggering hypersensitive cell death when transiently expressed in Nicotiana benthamiana leaves. Virus-induced gene silencing (VIGS) of TuNHL1 using the barley stripe mosaic virus (BSMV) system in the resistant T. urartu accession PI428309 significantly compromised resistance to the Pst isolate CY33, indicating that TuNHL1 is essential for YrU1-triggered immune responses. Moreover, overexpression of TuNHL1 in both wheat and Arabidopsis thaliana enhanced resistance to powdery mildew following inoculation with their respective pathogens. Taken together, our results revealed important roles of TuNHL1 in YrU1-mediated stripe rust resistance and powdery mildew resistance.