ZED1-related kinases (ZRKs) from Aquilegia coerulea and Cinnamomum micranthum do not trigger autoactive cell death in Nicotiana benthamiana

ZED1-related kinases (ZRKs) are receptor-like cytoplasmic kinases (RLCK) that mediate pathogen effector recognition and hypersensitive cell death response via the intracellular immune receptor HOPZ-ACTIVATED RESISTANCE1 (ZAR1). To investigate the functional connection between ZAR1 and ZRK orthologs across flowering plant species, Adachi et al. (2022) cloned ZAR1 and ZRK homologs from Cinnamomum micranthum and Aquilegia coerulea. Here, we performed a transient gene expression screening to determine whether expression of wild-type ZRKs causes autoactive cell death in the model plant Nicotiana benthamiana. In total, we screened 13 and five ZRK genes from C. micranthum and A. coerulea, respectively. None of the tested ZRKs triggered macroscopic cell death response when expressed in N. benthamiana leaves. This indicates that C. micranthum and A. coerulea ZRKs are not autoactive and do not trigger cell death in the absence of their partner ZAR1.