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SPECIAL SESSION: Host-pathogen interactions at the plant surface

Stomata-mediated plant immune response against microbe invasion
Maeli Melotto - University of California, Davis.

The leaf epidermis represents a barrier that protects the plant against microbial invasion. Of particular importance in this tissue, are the natural pores, such as stomata, that provide ports of entry for pathogens allowing the establishment of endophytic colonization. However, stomata-mediated immune response reduces microbial internalization of leaves. Our recent research has provided evidence that this mechanism of plant resistance is employed towards a broad range of pathogens, including the phytopathogen Pseudomonas syringae and the human pathogens Salmonella enterica and the enterohemorrhagic Escherichia coli O157:H7. Interestingly, P. syringae and S. enterica, but not E. coli, can overcome stomatal defenses in Arabidopsis and lettuce. The mechanism by which they do so will be further discussed. Understanding stomatal defense mechanisms against phytopathogens and enterics may facilitate the implementation of control measures to decrease plant diseases as well as the contamination of edible leaves.