** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PLANT PATHOGENS CAUSE SERIOUS WORLDWIDE EFFECTS ON CROP PRODUCTION AND YIELD. PSEUDOMONAS SYRINGAE IS A BACTERIAL PATHOGEN THAT CAUSES DISEASE IN MANY PLANTS, INCLUDING TOMATO. P. SYRINGAE INJECTS EFFECTOR PROTEINS INTO THE PLANT USING A NEEDLE-LIKE SYRINGE. EFFECTOR PROTEINS TYPICALLY SUPPRESS PLANT IMMUNE PATHWAYS TO PROMOTE DISEASE, HOWEVER THEY CAN BE RECOGNIZED IN RESISTANT PLANT HOSTS. USING A STRAIN OF P. SYRINGAE THAT LACKS EFFECTORS, WE DISCOVERED IT CAUSES A STRONG IMMUNE RESPONSE IN WILD TOMATO, THAT IS DEPENDENT ON A FUNCTIONAL NEEDLE-LIKE SYRINGE. THIS WAS A SURPRISING RESULT AS THE IMMUNE RESPONSE IS USUALLY TRIGGERED BY EFFECTOR PROTEINS AND THIS STRAIN LACKS ALL EFFECTORS. IN ADDITION, WE FOUND THAT RECOGNITION IS STRONGER AND MORE PREVALENT IN WILD TOMATO COMPARED TO DOMESTICATED TOMATO, AND THAT EFFECTORS CAN SUPPRESS THIS RECOGNITION. UNDERSTANDING RECOGNITION COULD BE VERY USEFUL FOR ENGINEERING NEW SOURCES OF RESISTANCE IN CULTIVARS BECAUSE THE NEEDLE-LIKE SYRINGE SYSTEM IS FOUND IN MANY PLANT-INFECTING BACTERIA, POTENTIALLY ALLOWING FOR RECOGNITION OF MULTIPLE BACTERIAL SPECIES. IDENTIFYING CAUSATIVE GENES FOR RECOGNITION OF THE NEEDLE-LIKE SYRINGE MAY PROVIDE ADDITIONAL TOOLS FOR CROP PROTECTION AND FOOD SECURITY.TO BETTER UNDERSTAND THE RECOGNITION OF THIS STRAIN, WE WILL TEST EXISTING OR CREATE NEW P. SYRINGAE MUTANTS AND DETERMINE IF THE IMMUNE PHENOTYPE IS RETAINED OR LOST. WE WILL TEMPORARILY EXPRESS CANDIDATE BACTERIAL GENES IN SOLANACEOUS (TOMATO, TOBACCO, ETC) SPECIES AND SEE IF THEY CAUSE THE IMMUNE RESPONSE. WE WILL TEST SPECIFIC EFFECTOR GENES FOR SUPPRESSION OF THE IMMUNE RESPONSE, AND CHARACTERIZE PLANT-BACTERIAL INTERACTIONS AND HOST RESPONSES. WE WILL TEST A WIDE RANGE OF TOMATO LINES FOR THEIR ABILITY TO RECOGNIZE THE EFFECTORLESS STRAIN OF P. SYRINGAE. IN ADDITION, WE WILL TEST GENES OF INTEREST IN TOMATO OR TOBACCO SPECIES FOR THEIR ROLE IN THE IMMUNE RESPONSE. WE WILL CONTINUE TO TRAIN DIVERSE POSTDOCS, GRADUATE AND UNDERGRADUATE SCIENTISTS, AND COLLABORATE WITH A HBCU. WE WILL CONNECT SCIENTIFIC TRAINING AND AGRICULTURAL OUTREACH THROUGH INTERACTIONS BETWEEN SCIENTISTS AND GROWERS, AS WELL AS THE GENERAL PUBLIC AT PUBSCIENCE EVENTS. THIS PROJECT WILL HELP IDENTIFY NEW POTENTIAL TARGETS FOR CROP PROTECTION, IN ORDER TO REDUCE CROP LOSSES FROM DISEASE AND STRENGTHEN FOOD SECURITY. THIS WORK WILL ALSO HELP TRAIN, EXPAND AND DIVERSIFY THE SCIENTIFIC WORKFORCE, BRIDGE CONNECTIONS BETWEEN SCIENTISTS AND GROWERS, AND ENHANCE SCIENCE COMMUNICATION WITH THE GENERAL PUBLIC.