Plant pathogens such as Ralstonia, Xylella or Xanthomonas are responsible for devastating vascular systemic infections in crops. The genetic basis of plant vascular immunity are poorly understood thus limiting the design of resistant or tolerant crops. With a focus on black rot disease of Brassicaceae caused by the devastating crop pest Xanthomonas campestris (Xc), the NEPHRON project aims to identify and characterize different layers of plant immunity at the hydathodes which are natural entry points for Xc. Hydathodes are plant organs located at the leaf margin and where guttation occurs. The NEPHRON project will establish the genetics of hydathode differentiation and physiology and its importance for the susceptibility to black rot disease. The results acquired in Arabidopsis and in different elite Brassica varieties will help to design knowledge-based strategies to better control vascular pathogens.