P-020 - Cross-kingdom resistance provided by the wheat integrated-domain NLR, TaADNR1

Wheat production is threatened by both obligate biotrophic rusts and specialised aphids. Puccinia striiformis f. sp. tritici (Pst) is a devastating obligate pathogen that causes severe economic losses world-wide with Diuraphis noxia occurring together with Pst. Recently, TaAdnr1 was identified as an integrated domain NLR that contains ankyrin repeats before the coiled-coil domain and an integrated WRKY domain following the leucine-rich repeat domain. This protein plays a role in detection of D. noxia effectors and plays a role in the wheat defence response. Its Triticum urartu homologue, YrU1, was identified to play a role in the Pst resistance response. Here we show that TaAdnr1 plays a role in both wheat resistance against Pst and D. noxia. Transient silencing of TaAdnr1 in a wheat line with resistance against both Pst and D. noxia resulted in development of uredia characteristic of a susceptible interaction upon infection. A similar suppressed resistance response was observed upon infestation with D. noxia. The aphid numbers and fecundity were similar to aphids infesting a susceptible wheat line. These results indicate that hexaploid wheat TaAdnr1 and its progenitor homologue YrU1 determines the wheat resistance response when challenged by biotrophic organisms from different multiple kingdoms. This may indicate shared effector strategies by obligate fungi and host specific aphids to target WRKY transcription factors within cereals to overcome a host resistance response.