The Arabidopsis CERK1‐associated kinase PBL27 connects chitin perception to MAPK activation The neighbor‐joining phylogenetic tree was created using ClustalW on the DNA Data Bank of Japan (http://www.ddbj.nig.ac.jp/). The full‐length protein sequence for each MAPKKK was used for the alignment. The phylogenetic tree was generated from the modified alignment with Treeview X software. The growth of yeast colonies on plates (‐ULWH) lacking uracil (U), leucine (L), tryptophan (W), and histidine (H) with 5 mM 3‐aminotriazole (3‐AT) indicates a positive interaction. The 3‐AT is a competitive inhibitor of the HIS3 gene product (histidine synthase), which is the reporter gene for the interaction in the yeast two‐hybrid assay. FL: full length, N: N‐terminal domain, KD: kinase domain, C: C‐terminal domain. IF THIS IMAGE HAS BEEN PROVIDED BY OR IS OWNED BY A THIRD PARTY, AS INDICATED IN THE CAPTION LINE, THEN FURTHER PERMISSION MAY BE NEEDED BEFORE ANY FURTHER USE. PLEASE CONTACT WILEY'S PERMISSIONS DEPARTMENT ON PERMISSIONS@WILEY.COM OR USE THE RIGHTSLINK SERVICE BY CLICKING ON THE 'REQUEST PERMISSIONS' LINK ACCOMPANYING THIS ARTICLE. WILEY OR AUTHOR OWNED IMAGES MAY BE USED FOR NON-COMMERCIAL PURPOSES, SUBJECT TO PROPER CITATION OF THE ARTICLE, AUTHOR, AND PUBLISHER. EMBO J, Volume: 35, Issue: 22, Pages: 2468-2483, First published: 27 September 2016, DOI: (10.15252/embj.201694248)