Immunity at hydathodes controls bacterial infection ($)

Hydathodes are the sites of guttation, which is a process by which water and solutes are pushed out of leaves by the force of root pressure when the rate of transpiration is low (for example at night).  Hydathodes have numerous stomata-like pores and are located near vascular ends. Like stomata, hydathodes provide infection opportunities for pathogens. Cerutti et al. examine the physiology and anatomy of hydathodes in Arabidopsis and cauliflower (Brassica oleracea var. botrytis). They show that like stomata, hydathodes respond to light, CO₂ and ABA.  Upon inoculation with pathogens or the epitope flg22, there was no evidence for pre-invasive immunity at hydathodes, although post-invasive immunity including production of reactive oxygen species and development of necrotic lesions was observed. Plant Physiol. 10.​1104/​pp.​16.​01852