GRAPES ARE THE HIGHEST VALUE FRUIT CROP IN THE US,CONTRIBUTING MORE THAN $162 BILLION TO THE NATIONALECONOMY EACH YEAR AND WITH A 36% OF THE PRODUCTION BEINGEXPORTED.IT IS PREDICTED THAT50-81% OF THE GRAPEVINE GROWING ACREAGE IN THE USA WILL FALL OUT OF PRODUCTION DUE TO WEATHER CHANGES BY 2040.IF THIS PROJECTION BECOMES A REALITY IT WOULD HAVE DEVASTATING EFFECTS BOTH ON LOCAL COMMUNITIES AND GLOBAL WINE AND GRAPE INDUSTRY.MOREOVER,EPISODES OF EVEN RELATIVELY MILD ABIOTIC STRESSCAN DRAMATICALLY INCREASE SUSCEPTIBILITY OF PLANTS TO DISEASE, WHICHADDS URGENCY FOR A BETTER UNDERSTANDING OF PLANT TOLERANCE TO ABIOTIC STRESS. THIS URGENTLY DEMANDS THE BREEDING OF VARIETIES MORE RESILIENT TO PERIODS OF ENVIRONMENTAL STRESS, WITHOUT LOSING FRUIT QUALITY.TO-DATE PROGRESS IN THIS AREA HAS BEEN HINDERED AS GRAPEVINE, LIKE MANY OTHER PERENNIAL WOODY CROPS, IMPOSES PROTRACTED(25 TO 30 YEARS)AND COSTLY BREEDING PROGRAMSDUE TO LENGTHYEVALUATION PERIODS IN EACH BREEDING STEP.EPIGENETIC PRIMING (EP) REFERS TO A SET OF MOLECULAR MECHANISMS BY WHICH PLANTS CAN INCREASE THEIR RESILIENCE TO STRESS BYGENERATING AN EPIGENETIC MEMORY OF THEIR ENVIRONMENTAFTER RECOGNITION OF SPECIFIC ENVIRONMENTAL SIGNALS. PREVIOUS OBSERVATIONS BOTH IN ANNUAL MODEL PLANTS AND CROPS HAVE SHOWN THAT SUCH MEMORY OF STRESS CAN LAST SEVERAL DAYSAND TRANSMITTED OVER MULTIPLE SEXUAL GENERATIONS. THE USE OFEPIGENETIC PRIMING HAS THE POTENTIAL TO ACCELERATE THE PRODUCTION OF LOCALLY ADAPTED CULTIVARS OF PERENNIAL CROPS. HOWEVER, FOR THIS TO BE EFFECTIVE, VEGETATIVE PROPAGATING METHODOLOGIES MUST ALLOW THE MAINTENANCE OF EPIGENETIC MEMORY. UNFORTUNATELY, THE MECHANISMS REGULATING EPIGENETIC MEMORY IN PERENNIALS AND THE EFFECT THAT VEGETATIVE PROPAGATION HAS ON ITS MAINTENANCE ARE NOT WELL UNDERSTOOD.OUR PRELIMINARY RESULTSINDICATE THAT AGE ACQUIRED EPIALLELES CAN BEMAINTAINED OR ERASED DURING THE GENERATION OF VEGETATIVE PROPAGULES DEPENDING ON THE VEGETATIVE PROPAGATION APPROACH USED.THIS PROJECT AIMS TO UNRAVELTHE PROCESSES MEDIATING PLANT AND METHYLOME REJUVENATION DURING VEGETATIVE PROPAGATION OF GRAPEVINES.TO ACHIEVE THE GOALS AND OBJECTIVES OF THIS PROJECT,OVER THE NEXT THREE YEARS, WE WILLUSEAN INNOVATIVE COMBINATION OF SEXUAL AND VEGETATIVE CLONAL PROPAGATION OF GRAPEVINES, TO CONDUCT A MULTI-OMIC COMPARATIVE ANALYSIS OF EPIGENETIC AND GENE REGULATORY MECHANISMS IN TISSUES DERIVED FROM EACH TYPE OF PROPAGATION AT A WHOLE GENOME LEVEL AND WITHIN THE WELL UNDERSTOOD FRAMEWORKS OF FLAVONOID BIOSYNTHESIS AND WATER STRESS RESPONSE, TO UNCOVER THE MOLECULAR PROCESSES UNDERLYING PLANT REJUVENATION DURING VEGETATIVE PROPAGATION.UNRAVELLING THE MECHANISMS REGULATING THE MAINTENANCE OF EPIGENETIC MEMORY DURING VEGETATIVE PROPAGATION, WILL ALLOW BREEDERS TO GENERATE LOCALLY ADAPTED GRAPEVINE VARIETIES WITH HIGHER LEVELS OF TOLERANCE TO ABIOTIC AND BIOTIC STRESSES. THE KNOW-HOWGENERATED DURING THIS PROJECT WILL GIVE AMERICAN BREEDERS, NURSERIES AND GROWERS A COMMERCIAL ADVANTAGE BY SIGNIFICANTLY REDUCING THE TIME NEEDED TO GENERATE NEW PERENNIAL CROP VARIETIES. THE FINDINGS OF THE PROPOSED RESEARCHWILL PROVIDE KNOWLEDGE TRANSFERABLE TO OTHERAGRICULTURALLY-IMPORTANTPERENNIAL CROPS.