TREHALOSE AND TREHALOSE-6-PHOSPHATE INDUCE STOMATAL MOVEMENTS AND INTERFERE WITH ABA-INDUCED STOMATAL CLOSURE IN GRAPEVINE

Aims: The effects of trehalose and trehalose-6-phosphate (T6P), among other sugars, were assessed on grapevine stomatal movements. Methods and results: Epidermal peels were used to assess the effects of sugars. Low concentrations of trehalose and T6P (1 mu M) induced an osmotic-independent reduction of the stomatal aperture in light conditions. Furthermore, ABA-induced stomatal closure was reduced by sugar application in association with lower accumulation of reactive oxygen species in guard cells. Similar effects, although weaker, were observed in response to the disaccharides sucrose and maltose, but not in response to the monosaccharides fructose and glucose. Conclusion : This study clearly highlights the effects of sugars, especially trehalose and T6P, on grapevine stomatal movements. Significance and impact of the study: This is the first time that such effects are described in grapevine and the results obtained provide new insights about the role of sugars on stomatal regulation at the whole plant level.