Responses of grapevine cells to physiological doses of ethanol, among which induced resistance to heat stress

Grapevine naturally endures stresses like heat, drought, and hypoxia. A recent study showed very low oxygen levels inside grape berries, linked to ethanol content. Other studies have established the link between ethanol and tolerance to various stresses: heat stress, drought, and high salinity. The causes of such a tolerance are not well understood. In our study, three-week-old Gamay calli, Vitis vinifera, were characterised for their endogenous oxygen levels and endogenous ethanol concentration. Subsequently, a transcriptomic study of these cells was conducted, 6 and 24 hours after treatment with 1 mM ethanol. After 6 hours, ethanol addition led to 386 differentially expressed genes, with a 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, sHSPs playing a potentially crucial role in this adaptive response.