Responses of grapevine cells to physiological doses of ethanol, including induced resistance to heat stress.

Grapevine is naturally exposed to stresses like heat, drought, and hypoxia. A recent study found very low oxygen levels inside grape berries, linked to ethanol content. Other studies have established a link between ethanol and tolerance to various stresses: heat, drought and high salinity. The causes of such tolerances are not well understood. In our study, 3-week-old Gamay calli, Vitis vinifera, were characterized for endogenous oxygen and ethanol concentrations. A global transcriptomic study was conducted to explore the response of grapevine cells to ethanol, which, to our knowledge, is the first such analysis in plants. RNA-seq analysis was performed on cells at 6 and 24 h after treatment with 1 mM ethanol. After 6 h, ethanol addition led to 386 differentially expressed genes (DEGs), with notable upregulation of genes related to heat response, especially small Heat Shock Proteins (sHSPs). Further experiments showed that ethanol priming in grape cells or in Arabidopsis seedlings reduced pigment and electrolyte leakage under heat stress, respectively. This study supports the idea that ethanol priming helps protect plants against heat stress and provides a valuable RNA-seq dataset for further research into the underlying mechanisms, where sHSPs play a potentially crucial role in this adaptive response.