Performing Department
(N/A)
Non Technical Summary
Grapevine freeze damage threatens grape production globally. As grape buds emerge from winter dormancy and approach budbreak, they lose cold tolerance ("deacclimate") and become increasingly susceptible to low temperature damage. Grape buds contain crop potential for the annual growing season, and low temperature damage can causeconsiderable economic loss for grape growers. Global warming is expectedto advance the rate of bud deacclimation and time of budbreak in spring, but spring freeze events are not projected to decrease uniformly. In order to adapt to global warming and the resulting changes to early season phenology, we must advance our fundamental knowledge of grapevine dormancy and bud cold tolerance and create mitigation strategies for grape growers.The proposed researchwill investigate the role of the plant hormone abscisic acid (ABA) in regulating dormancy and cold tolerance in grape buds across different genotypes relevant to US production.The proposed experiments will test whether the application of a synthetic ABA productin autumn initiates faster cold acclimation and higher bud cold tolerance under ambient conditions. In simulation of global warming, the proposed research will also test if the synthetic ABA product effectively delaysbud deacclimation and budbreak in spring under ambient and warmer temperature scenarios.Together, research outcomes from this grantwill advance scientific knowledge on the role of ABA in grapevines and improve grower-focused outcomes (e.g., plant breeding and product development) for climate adaptation in vineyards.
Animal Health Component
45%
Research Effort Categories
Basic
45%
Applied
45%
Developmental
10%
Goals / Objectives
Global warming is advancing grapevine budbreak, and grape buds are becoming moresusceptible to early season cold damage. In Vitisvinifera and Vitisinterspecific hybrid genotypes, the proposed research goals are to 1) advance fundamental knowledge on the role of abscisic acid (ABA)in bud dormancy and cold tolerance, 2) determine the impact of warmer temperatures on bud deacclimation and ABA concentration, and 3) test whether the exogenous application of a synthetic ABA product can offset faster bud cold deacclimation due to warming. Together, these objectives will advance scientific knowledge on the role of ABA in grapevines and improve grower-focused outcomes (e.g., plant breeding and product development) for climate adaptation in vineyards.Objective 1: Examine how bud ABA concentration relates to a) morphological traits attributed to dormancy induction (e.g., leaf senescence), b) bud cold tolerance throughout dormancy, and c) the rate of bud deacclimation and time of budbreak.Objective 2: Determine how elevated temperatures throughout ecodormancy impact the rate of grape bud deacclimation, ABA concentration, gene expression, and budbreak.Objective 3: Test whether the application of a synthetic ABA analog to grapevines prior to leaf-fall a) induces earlier dormancy responses (e.g., leaf senescence) and higher bud cold tolerance during dormancy, and b) delays the rate of bud deacclimation and time of budbreak under ambient and elevated temperature scenarios.
Project Methods
Design and MethodsAmong grapevine genotypes that are relevant to US grape production, the proposed research experiments will 1) examine the role of the plant hormone abscisic acid (ABA) in regulating bud dormancy and bud cold tolerance, 2) determine how elevated temperatures impact rate of bud deacclimation (loss of cold tolerance) and time of budbreak, and 3) test if applying a synthetic ABA analog to grapevines mitigates the negative impacts of elevated temperatures on bud dormancy and cold tolerance.Experimental design:In brief, this researchwill be performed grapevines from four Vitis genotypes that have varied onsets of cold acclimation, maximum cold tolerance, and rates of deacclimation.The experimental design will be a 4 x 2 x 2 factorial completely randomized design. The primary factor will be genotype, the secondary factor will be ABA treatment, and the tertiary factor, nested within the secondary factor, will be heat treatment. Abscisic acid in grape buds, along with rate of cold acclimation, will be measured throughout the fall and winter in all genotypes. A synthetic ABA productwill be applied to a subset of vines in the fall, and ABA concentration and cold acclimation in grape buds will be measuredthroughout the fall and winter. In the spring, a subset of sprayed and non-sprayed ABA vines, from all genotypes, will be placed in an elevated temperature regime and 1) ABA concentration, 2) bud deacclimation rate, and 3) the bud transcriptome will be evaluated and compared to vines growing under ambient vineyard conditions.Data analysis. Bud ABA concentration, bud cold tolerance, and bud phenology data at each sampling timepoint throughout the fall, winter, and spring will be subjected to 3-way Analysis of Variance to compare four factors of genotype, two factors of ABA spray, two factors of heat, and their interactions. In the spring, bud gene expression will be used to determine which mechanisms associated with bud dormancy and cold tolerance are impacted by heat and which pathways the synthetic ABA analog spray influences during bud deacclimation.EvaluationSuccessful completion of the outlined efforts will be evaluated by thegrant's primary and collaborating mentors, the scientific community at large, extension personnel, and grape growers. Milestones for the proposedresearch objectives include 1) conducting the outlined experimental set up, treatment applications, and sampling for the research experiments, 2) conducting the metabolomic and transcriptomic analyses within the proposed grant timeframe, 3) conducting data analyses to use in presentations (e.g., conference, extension, and guest lectures) and 4) submission of results to a peer-reviewed scientific journal. Research results will also be communicated to grape growers through talks at extension meetings and webinars.