Molecular insights into water stress responses in the ‘Italia’ table grape cultivar

Stress induced by drought can drastically affect grapevine physiology, morphology, and productivity, leading to complex molecular and physiological responses. In this study, we investigated drought-activated genes in Vitis vinifera cultivar ‘Italia’ over 37 days of water deprivation. Using real-time PCR (qRT-PCR) we analyzed the expression variations of VviPP2C4, VviPP2C8, and VviHSP18, key genes known to be involved in abscisic acid (ABA) signaling and stress response adaptation. The analysis showed that while VviPP2C4 expression increased significantly in non-irrigated plants, for VviPP2C8 no significant variations were detected. This data suggests the involvement of VviPP2C4 in the stress responses system. In addition, a significant overexpression of the VviHSP18 gene suggests its implications in cellular protection mechanisms to counteract the damage caused by the lack of water. These results confirm the involvement of specific protein phosphatase (PP2C) and heat shock proteins (HSP) in regulating grapevine response and adaptation to drought stress, deepening the knowledge of the genetic architecture of drought tolerance in grapevine. These finds could allow the development of new strategies for breeding of cultivars with enhanced drought resilience as well as sustainable grape growing practices.