Fig. 1. FLS2 homologues exhibit distinct perception range and magnitude.
a, Maximum-likelihood, midpoint-rooted phylogenetic tree of bacterial flagellin. Major clades are collapsed in a genera-dependent manner and coloured on the basis of taxonomic classes. Branch thickness indicates bootstrap support. The number of unique flg22 peptide variants for each genus is given in a grey box. b, Frequency of flg22 variants characterized in this study in comparison with all flg22 variants mined in ref. 18. c, WebLogo and sequence alignment of flg22 from plant pathogenic bacteria, coloured bars represent different bacterial classes. d, Normalized ROS production after flg22 treatment (100 nM). NbFLS2 perception was analysed in wild-type N. benthamiana. Other FLS2 homologues were transiently expressed in the N. benthamiana fls2-1/2 CRISPR–Cas9 mutant. Leaf disks for ROS assays were collected 24 h after infiltration. Normalized ROS levels were calculated by adjusting maximum relative light unit (RLU) averages to a 0 to 100 scale. Water was set to 0 and Pae flg22 was set to 100. Data points below a value of 10 are depicted as white bubbles. e, MAPK phosphorylation triggered by flg22 variants (100 nM). FLS2 expression occurred as described in d and tissue was collected 24 h after infiltration. Coomassie brilliant blue (CBB) staining indicates protein loading. All experiments were repeated at least three times independently with similar results. Nb, Nicotiana benthamiana; Qv, Quercus variabilis; Rso, Ralstonia solanacearum; Tj, Trachelospermum jasminoides; Xfr, Xanthomonas fragariae; Xor, Xanthomonas oryzae.