Inactivation of a wheat protein kinase gene confers broad-spectrum resistance to rust fungi

Abstract

Wheat crops are frequently devastated by pandemic stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). Here, we identify and characterize a wheat receptor-like cytoplasmic kinase gene, TaPsIPK1, that confers susceptibility to this pathogen. PsSpg1, a secreted fungal effector vital for Pst virulence, can bind TaPsIPK1, enhance its kinase activity, and promote its nuclear localization, where it phosphorylates the transcription factor TaCBF1d for gene regulation. The phosphorylation of TaCBF1d switches its transcriptional activity on the downstream genes. CRISPR-Cas9 inactivation of TaPsIPK1 in wheat confers broad-spectrum resistance against Pst without impacting important agronomic traits in two years of field tests. The disruption of TaPsIPK1 leads to immune priming without constitutive activation of defense responses. Taken together, TaPsIPK1 is a susceptibility gene known to be targeted by rust effectors, and it has great potential for developing durable resistance against rust by genetic modifications.

Keywords: broad-spectrum resistance; pathogenic factor; susceptibility gene; wheat stripe rust.