Exogenous N‐acyl‐homoserine lactones enhance the expression of flagella of Pseudomonas syringae and activate defence responses in plants Comparisons of differentially expressed genes. The circles display the number of genes uniquely regulated in Pseudomonas syringae 11528 grown with N‐hexanoyl‐homoserine lactone (C6‐HSL) (Pta_S1), N‐(3‐oxo‐hexanoyl)‐homoserine lactone (3OC6‐HSL) (Pta_S2) or both N‐acyl‐homoserine lactones (AHLs) (Pta_DS) compared with their regulation in P. syringae 11528 grown without AHLs. The circles also show the number of commonly and uniquely regulated genes under different conditions. 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. Molecular Plant Pathology, Volume: 19, Issue: 1, Pages: 104-115, First published: 18 October 2016, DOI: (10.1111/mpp.12502)