Tetralone-ABA enhances winter cold acclimation, reduces deacclimation, and delays budbreak in V. vinifera and V. hybrid grapevines

Abstract

Climate change-related acute winter freezes and unseasonal false springs have become significant and predictable risks for grape growers across North America and Eurasia. Novel strategies to enhance resilience during the dormant season, particularly by improving bud cold hardiness and delaying budbreak, are urgently needed for the sustainability of grape and wine production. In this study, we evaluated a synthetic abscisic acid (ABA) analog, tetralone-ABA (ABA-1102), as a sprayable product for inducing these traits in three grapevine cultivars: Riesling, Cayuga White, and their progeny, Aravelle. We determined that post-harvest foliar application of tetralone-ABA promoted early leaf senescence, induced cultivar-specific bud cold hardiness enhancement during cold acclimation, slowed deacclimation under controlled and field conditions, and delayed budbreak in spring without affecting growing season phenology, physiology or harvest yield. Transcriptomic analysis of during deacclimation assays suggests that tetralone-ABAs effect on delaying deacclimation may result from its suppression of the activation of growth-related pathways under growth-permissive conditions. Detailed investigations of these pathways indicate that tetralone-ABA may have modulated critical biological processes such as cell wall remodeling, sugar metabolism, and ABA signaling. Overall, this study provides novel insights into the genetic control of grapevine deacclimation, highlights ABAs role in grapevine dormant season physiology, and demonstrates tetralone-ABAs potential as a promising tool for improving dormant season viticulture resilience, offering a new strategy to protect grapevines against the increasing threats posed by climate change.