Identification of water channels and analysis of their expression pattern during strawberry fruit ripening

AMODEO G, MUT P, BUSTAMANTE C, ALLEVA K, SUTKA M, MARTÍNEZ G, CIVELLO M

Chateau Du Lac , Genval. Brussels.

Conferencia; Internacional Conference on Aquaporins; 2005

Strawberry is a (false) fruit that develops and ripens rapidly, with fast softening, therefore forcing a brief commercial life. Studying the processes involved in ripening, like softening, is consequently crucial in establishing strategies to extend post harvest life of this commercial fruit. Fruit softening is partially due to cell wall degradation, and a growing number of enzymes related to this process have been characterized. However, the contribution of fruit turgor and the water movement pathways should be considered also. Hence, the aim of our work was to isolate water channels and to characterize their expression and function during strawberry fruit ripening. A 1.2 Kb fragment (FaMIP) was isolated from a cDNA library constructed from ripe strawberry fruit (cv Chandler). The predicted protein sequence had high homology to aquaporin gene family, mainly to the PIP subgroup. Northern-blot analysis revealed that FaMIP expresses specifically in fruit tissue and that its expression increases through strawberry fruit ripening. In addition, the expression is repressed by auxins. Preliminary results showed low water permeability when FaMIP was expressed in Xenopus oocytes.    We here report that proteins that are homologues to water channels are present in strawberry fruit and modify their expression pattern during fruit ripening.