**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** ROOT LESION NEMATODES BELONGING TO THE GENUS PRATYLENCHUS, ARE MICROSCOPIC WORMS THAT BURROW WITHIN THE ROOTS OF PLANTS IN ORDER TO FEED ON ROOT TISSUES. AS ONE CAN IMAGINE, THEIR BURROWING NOT ONLY IMPAIRS ROOT FUNCTION I.E. THE ROOT'S ABILITY TO ABSORB WATER AND NUTRIENTS, BUT IT ALSO MAKES IT EASIER FOR OTHER PATHOGENS SUCH AS BACTERIA, FUNGI, AND OTHER NEMATODE SPECIES TO INVADE THE ROOTS. ROOT LESION NEMATODES TYPICALLY HAVE WIDE HOST RANGES THAT MAKE THEIR MANAGEMENT DIFFICULT. GIVEN THEIR COMBINATION OF ROOT DAMAGE AND WIDE HOST RANGES, ROOT LESION NEMATODES REPRESENT A MAJOR PROBLEM FOR CROP PRODUCTION WORLDWIDE.WHILE SEVERAL ROOT LESION NEMATODE SPECIES AFFECT WHEAT, PRATYLENCHUS NEGLECTUS IS THE MOST COMMON IN WHEAT GROWING REGIONS OF THE UNITED STATES. MONTANA IS TYPICALLY THE THIRD OR FOURTH LARGEST PRODUCER OF WHEAT IN THE UNITED STATES; AND WITHIN MONTANA, P. NEGLECTUS REPRESENT AN 80-MILLION-DOLLAR-A-YEAR CONUNDRUM. ITS MANAGEMENT WITHIN THE STATE CURRENTLY RELIES ON ROTATIONS TO THE NEMATODE RESISTANT CROPS: PEAS, LENTILS, AND BARLEY. UNFORTUNATELY, THESE CROPS ARE LESS PROFITABLE THAN WHEAT AND RECENTLY NEMATODE PATHOTYPES THAT FEED ON LENTIL AND BARLEY HAVE BEEN IDENTIFIED WITHIN THE STATE. LUCKILY FOR MONTANA, PLANT PATHOLOGISTS AND BREEDERS HAVE DEVELOPED LOCALLY ADAPTED WHEAT LINES THAT RESIST THE BURROWING AND MULTIPLICATION OF ROOT LESION NEMATODES AS DETERMINED IN GREENHOUSE TRIALS. PRIOR TO THEIR RELEASE AS CULTIVARS, THE PERFORMANCE OF THESE LINES WILL BE EVALUATED ACROSS SEVERAL DIFFERENT MONTANA ENVIRONMENTS AND ROOT LESION NEMATODE POPULATIONS (INCLUDING THOSE THAT CAN ATTACK LENTIL AND BARLEY). GIVEN THE NEMATODE'S REPUTATION FOR AFFECTING OTHER MICROBES WITHIN THE SOIL, THE DEPLOYMENT OF NEMATODE RESISTANT CULTIVARS SHOULD HAVE DRAMATIC POSITIVE EFFECTS ON THE ROOT AND SOIL MICROFLORA. THE PURPOSE OF THIS SEED PROJECT IS TO DETERMINE THE SECONDARY EFFECTS DEPLOYMENT OF NEMATODE RESISTANCE HAS ON THE ROOT AND SOIL HEALTH. THE EXPECTATIONS ARE THAT GROWING RESISTANT CULTIVARS WILL NOT ONLY DECREASE THE DIRECT DAMAGE ROOT LESION NEMATODES CAUSE TO WHEAT ROOTS BUT WILL ALSO EFFECT A DECLINE IN OTHER ROOT PATHOGENS/DISEASES AND AN INCREASE IN POPULATIONS OF BENEFICIAL SOIL MICROBES, THAT IS TO SAY NEMATODE RESISTANT CULTIVARS WILL INCREASE OVERALL ROOT AND SOIL HEALTH. TO DETERMINE THESE EFFECTS, BREEDING LINE PERFORMANCE TRIALS WILL BE MONITORED EXTENSIVELY USING TRADITIONAL VISUAL ASSESSMENTS OF DISEASE SEVERITIES, CULTURAL ISOLATION OF PATHOGENS FROM ROOT TISSUES, AND MODERN MOLECULAR ASSESSMENT OF FUNGAL AND BACTERIAL COMMUNITIES ASSOCIATED WITH SUSCEPTIBLE AND RESISTANT BREEDING LINES. THE BENEFITS OF THESE STUDIES WILL INCLUDE BETTER PREDICTIONS OF FUTURE DISEASE DYNAMICS FOR AREAS WHERE RESISTANT CULTIVARS ARE GROWN AND THE IDENTIFICATION OF SPECIFIC BACTERIAL COMMUNITY MARKERS ASSOCIATED WITH NEMATODE RESISTANCE. THE LATTER IS DESIRABLE BECAUSE SOIL BACTERIA ARE MORE RESPONSIVE TO GENETIC VARIABILITY IN P,LANTS THAN NEMATODES AND SO BACTERIAL CHANGES ASSOCIATED WITH RESISTANTGENOTYPES HOLD THE POTENTIAL OF BEING A CHEAPER AND FASTER TOOL FOR THE INITIAL SCREENING RESISTANT WHEAT GENOTYPES THAN THE TRADITIONAL MONITORING OF NEMATODE POPULATIONS. AS PLANTS OFTEN ENHANCE ROOT HEALTH THROUGH THE BENEFICIAL MANIPULATION OF BACTERIAL ASSEMBLAGES, THE OBSERVED CHANGES IN THE BACTERIAL COMMUNITY MAY ALSO REPRESENT THE MECHANISM BY WHICH RESISTANT WHEAT GENOTYPES ACHIEVE BETTER OVERALL ROOT HEALTH.