Tempo of gene regulation in wild and cultivated Vitis species shows coordination between cold deacclimation and budbreak

Abstract

Dormancy release, loss of cold hardiness and budbreak are critical aspects of the annual cycle of deciduous perennial plants. Molecular control of these processes is not fully understood, and genotypic variation may be important for climate adaptation. Single-node cuttings from wild (Vitis amurensis, V. riparia) and cultivated Vitis genotypes (V. vinifera ‘Cabernet Sauvignon’, ‘Riesling’) were collected from the field during winter and placed under forcing conditions. Cold hardiness was measured daily, and buds were collected for RNA-Seq until budbreak. Field-collected single-node cuttings of ‘Riesling’ were treated with abscisic acid (ABA), and cold hardiness and budbreak at 7 °C were tracked. Wild Vitis genotypes had faster deacclimation and budbreak than V. vinifera. Temperature-sensing related genes were quickly and synchronously differentially expressed in all genotypes. ABA synthesis was down-regulated in all genotypes, and exogenous ABA prevented deacclimation. Ethylene- and oxidative stress-related genes were transiently up-regulated. Growth-related genes were up-regulated and showed staggering similar to deacclimation and budbreak of the four genotypes. The gene expression cascade that occurs during deacclimation and budburst phenology of fast (wild) and slow (cultivated) grapevines appears coordinated and temporally conserved. This may extend to other temperate woody species and suggest constraints on identification of process-specific keystone genes.