Progress 07/01/24 to 06/30/25

Outputs
Target Audience:The target audience for this project includesviticulturists,plant breeders, extension personnel, and plant scientists. Research efforts also served an undergraduate mentee, who was trained in viticulture, data collection, data interpretation, and scientific communication. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?PD Persico led experimental design, setup, data collection, analysis, and mentoring, which advanced PD Persico's scientific training, leadership capacity, and professional development as a postdoctoral researcher. In fall 2024, PD Persico recruited an undergraduate research assistant to support data collection through spring 2025. This undergraduate student was successfully awarded a Penn State undergraduate research grant to work under PD Persico's mentorship. Throughout the project, the mentee gained hands-on experience in field- and greenhouse- based data collection and lab protocols. The mentee also developed skills in scientific communication and data presentation. PD Persico gained valuable experience in mentoring, supervision, and research leadership, while the undergraduate mentee gained exposure to hypothesis-driven research. This collaboration culminated in the undergraduate presenting a research poster at the Spring 2025 Gamma Sigma Delta Research Expo at Penn State, showcasing preliminary results from this experiment. How have the results been disseminated to communities of interest?Preliminary results from this project were shared with the academic community through an undergraduate student-led poster presentation at theGamma Sigma Delta Research Expo at Penn State University in spring 2025. The poster, co-authored bythe undergraduate research mentee and PD Persico, presented initial findings on how tetralone ABA impacts dormancy induction and cold tolerance. The poster was presented to expo attendees, includingfaculty, students, and extension educators. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, PD Persico will receive training in the extraction and quantification of plant hormones, with a focus on measuring both natural and synthetic abscisic acid (ABA) concentrations in grapevine buds (Obj.1 and 2). These analyses will be used to determinethe relationship between bud ABA levels and key growth stages like dormancy progression and cold acclimation infall and winter anddeacclimation and budbreak in spring (Obj. 1-3). PD Persico will begin preparing manuscripts and presentations based on the results from this experimentfor dissemination in peer-reviewed journals and at professional conferences.

Impacts
What was accomplished under these goals? PD Persicoconducted experimental set up and all field data collection during this reporting period. In spring2024, PD Persico potted and maintained 320 grapevines, which were grown at the research vineyard at the Penn State Horticultural Research Farm(University Park, PA). PD Persico assigned the grapevines totreatment groups in a 4×2×2 completely randomized factorial design before data collection began. The factors were(1) genotype (Cabernet Sauvignon, Chardonnay, Chambourcin, or Marquette), (2) Tetralone ABA treatment (no or yes), and (3) post-dormancy heat exposure (unheated or heated). For the vines receiving the "yes" tetralone ABA treatment, vines were sprayed withsynthetic ABA analog(+)-Tetralone ABA® (ABAzyne Bioscience Inc.) in mid-September 2024, while vines assigned to the "no" tetralone ABA treatment did not receive the synthetic ABA spray.PD Persico began data collection inSeptember 2024 to determine naturaland tetralone abscisic acid (ABA) concentration in grape buds (Obj. 1 and 3), the progression ofwhole-plantdormancy induction (e.g., leaf senescence and leaf fall) throughout fall(Obj. 1 and 3), the level of bud cold tolerance (Obj. 1 and 3),and the impact of tetralone ABA treatment on these parametersthroughout the fall and winter (Obj. 3). PD Persico measured dormancy induction weekly, collected bud samplesin early September,mid-October, and early Decemberfornatural and synthetic ABA quantification, and measured bud cold tolerance post-ABA spray inmid-Octoberand early December.Preliminary results suggest that tetralone ABA application increased leaf senescence and leaf fall for each genotype but did not markedlyincrease bud cold tolerance for any genotype when measured three- and 12-weeks post- tetralone ABA spray compared to non-tetralone ABA treated vines. In March 2025, vines were removed from winter storage at the Horticultural Research farm and transported to the Penn State University (University Park, PA) for the greenhouse activities associated with Objective 2. To begin the experiment, vines assigned to "no" heat treatment were placed in an unheated greenhouse that approximated outside temperatures, while vines assigned to the "yes" heat treatment were placed in a greenhouse that averaged 5-7ºCwarmer than the unheated greenhouse during the day and night. The vines remained in each greenhouse for approximately six weeks, during which PD Persico sampled all treatment combinations at least four times for natural and tetralone ABA quantification in buds (six times total for Cabernet Sauvignon), twice for bud cold tolerance, and twice weekly for bud phenological progression and time of budbreak. Preliminary results suggestthat vines treated with the tetralone ABA in September 2024 had higher bud cold tolerance during deacclimation than control vines, and the heat treatment did not affect the impact of ABA treatment. Furthermore, ABA-treated vines had slower phenological progression and budbreak compared to vines that were not treated with the tetralone ABA spray, but the magnitude of this difference depended on grapevine genotype and heat treatment. The concentration of natural and synthetic ABA in the grape buds from the samples collected in fall 2024 and spring 2025 will occur in the next reporting period to link all three research objectives.

Publications