THIS PROJECT SUPPORTS THE MISSION OF THE AGRICULTURAL EXPERIMENT STATION BY ADDRESSING THE HATCH ACT AREA(S) OF: PLANT AND ANIMAL PRODUCTION, PROTECTION, AND HEALTH; SUSTAINABLE AGRICULTURE; MOLECULAR BIOLOGY; AND, BIOTECHNOLOGY. HOST PREFERENCE AND PERFORMANCE OF PEST INSECTS ON PLANTS ARE LINKED TO HOST QUALITY (PRIMARY PLANT CHEMISTRIES) AND INDUCIBLE HOST DEFENSES (SECONDARY PLANT CHEMISTRIES). IN TURN, PLANT-FEEDING INSECTS HAVE EVOLVED MECHANISMS TO COUNTER HOST DEFENSE CHEMISTRIES. AT THE CENTER OF THIS INTERACTION ARE DIVERSE AND SPECIES-SPECIFIC REPERTOIRES OF SALIVARY GLAND (SG) PROTEINS SECRETED BY INSECTS DURING TISSUE PROBING OR FEEDING THAT CAN INDUCE OR SUPPRESS HOST DEFENSES, OFTEN ENHANCING INSECT FITNESS AND PROFITING PATHOGENS THEY TRANSMIT ("EFFECTORS"). ALMOST NOTHING IS KNOWN ABOUT SG-ENRICHED PROTEINS FOR THE WESTERN FLOWER THRIPS (WFT), AN INSECT THAT DAMAGES PLANTS BY FEEDING AND TRANSMITTING THE PLANT VIRUS, TOMATO SPOTTED WILT VIRUS (TSWV). THIS DEARTH OF INFORMATION RESTRICTS ADVANCES IN DEVELOPING HOST PLANTS WITH WFT AND TSWV RESISTANCE AND THREATENS SUSTAINABILITY OF EXISTING RESISTANT PLANT LINES. THIS PROPOSAL DESCRIBES AN INTEGRATED INVESTIGATION OF HOW TSWV INFECTION AFFECTS EXPRESSION OF SG-ENRICHED GENES ON TRANSCRIPTOME AND PROTEOME LEVELS, AND DETERMINES THE EXTENT TO WHICH TSWV RESPONSIVE GENES MODULATE MOLECULAR AND BIOLOGICAL INTERACTIONS BETWEEN WFT, TSWV AND PLANT DEFENSES. AIM 1: TEST HOW TSWV INFECTION STATUS, DEVELOPMENTAL STAGE AND SEX EFFECT EXPRESSION OF WFT SG-ENRICHED GENES. PREVIOUS WHOLE BODY TRANSCRIPTOMES SHOW DEVELOPMENTAL STAGE AND INFECTION STATUS AFFECT GENE EXPRESSION. OUR SG-SPECIFIC INVESTIGATIONS REVEAL A DECREASE IN EXPRESSION OF ONE SG-ENRICHED GENE IN INFECTED ADULT FEMALES. THESE DISCOVERIES WILL BE EXTENDED THROUGH COMPREHENSIVE TRANSCRIPTOMIC STUDIES OF SG FROM NON-INFECTED AND TSWV-INFECTED WFT LARVAE AND ADULTS (MALE AND FEMALE). AIM 2: TEST HOW TSWV-INFECTION STATUS, DEVELOPMENTAL STAGE AND SEX AFFECT THE PROTEOME OF WFT SALIVARY GLAND TISSUE AND SALIVA. THIS ANALYSIS WILL REVEAL THE COMPOSITION OF PROTEINS, INCLUDING SG-ENRICHED PROTEINS WITH KNOWN INVOLVEMENT IN FEEDING (I.E. EXTRA ORAL DIGESTION, EFFECTOR ACTIVITY) AND NOVEL WFT-SPECIFIC PROTEINS WITH NO KNOWN FUNCTION. AIM 3: TEST HOW DIFFERENTIALLY EXPRESSED PROTEINS FROM NON-INFECTED AND INFECTED WFT MAY VARY IN MODULATING PLANT DEFENSES AGAINST THE INSECT AND THE VIRUS IT TRANSMITS (TSWV) BY PHENOTYPIC-SCREENING OF PLANTS TRANSIENTLY-EXPRESSING SG-ENRICHED PROTEINS. AIMS 1 AND 2 WILL GUIDE SELECTION OF CANDIDATE GENES FOR PHENOTYPIC ANALYSIS. SPECIFIC HYPOTHESES WILL BE TESTED IN AIM 3 TO DISCOVER PLANT RESPONSES TO EXPRESSION OF SG-ENRICHED PROTEINS AND HOW THESE RESPONSES, AS WELL AS TSWV-INFECTION STATUS MODULATE WFT FITNESS, PHYSIOLOGY AND VIRUS TRANSMISSION. HOST PREFERENCE AND PERFORMANCE OF PEST ON PLANTS ARE LINKED TO HOST QUALITY AND INDUCIBLE HOST DEFENSES. IN TURN, PLANT-FEEDING INSECTS HAVE EVOLVED MECHANISMS TO COUNTER HOST DEFENSE CHEMISTRIES. AT THE CENTER OF THIS INTERACTION ARE DIVERSE AND SPECIES-SPECIFIC REPERTOIRES OF SALIVARY GLAND PROTEINS SECRETED BY INSECTS DURING PROBING OR FEEDING THAT CAN INDUCE OR SUPPRESS HOST DEFENSES, OFTEN ENHANCING INSECT FITNESS AND PROFITING PATHOGENS THEY TRANSMIT ("EFFECTORS"). ALTHOUGH CRITICAL FOR CREATION OF DURABLE HOST PLANT RESISTANCE AGAINST WFT AND TSWV, WE KNOW LITTLE ABOUT WFT'S SALIVARY PROTEIN REPERTOIRE. NOR DO WE HAVE FUNDAMENTAL INFORMATION ABOUT INTERACTIONS BETWEEN SG-ENRICHED TRANSCRIPTS, SALIVARY PROTEINS AND TSWV IN THE SGS; OR THE POTENTIAL ROLE OF THRIPS SALIVARY PROTEINS AS EFFECTORS, ELICITING AND/OR SUPPRESSING PLANT IMMUNE SYSTEMS AGAINST THE INSECT AND TSWV. THERE IS AN URGENT NEED FOR THE RESEARCH WE PLAN, WHICH WILL DISCOVER HOW TSWV INFECTION MODULATES SG-ENRICHED TRANSCRIPTS ON TRANSCRIPTOME AND PROTEOME LEVELS, AND DETERMINE THE EXTENT TO WHICH TSWV RESPONSIVE GENES ALTER MOLECULAR AND BIOLOGICAL INTERACTIONSBETWEEN WFT, TSWV AND PLANT DEFENSES. THESE FINDINGS WILL IDENTIFY SPECIFIC TARGETS AIMED AT INTERFERING WITH WFT FEEDING BEHAVIOR AND FITNESS, LEADING TO TSWV ACQUISITION, INOCULATION AND INFECTION OF PLANTS.