"Cloning, functional characterization, and co-expression studies of a novel aquaporin (FaPIP2;1) of strawberry fruit".

ALLEVA K.; MARQUEZ M.; VILLARREAL N.; MUT P.; BUSTAMANTE C.; BELLATI J.; MARTINEZ G.; CIVELLO P.; AMODEO G.

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2010 vol. 61 p. 3935 - 3945

0022-0957

In strawberry, the putative participation of aquaporins should be considered during fruit ripening. Furthermore, the availability of different firmness cultivars in this non-climacteric fruit outcomes as a very useful tool to also acknowledge their involvement in softening. In a previous work, we reported the cloning of a strawberry fruit-specific aquaporin -FaPIP1;1- which showed an expression profile associated with fruit ripening. Here, we cloned FaPIP2;1, an aquaporin subtype PIP2 and performed its functional characterization Xenopus oocytes. FaPIP2;1 gene encodes a water channel with high water permeability (Pf) that is regulated by cytosolic pH. Interestingly, the co-expression of both FaPIP subtypes resulted in an enhancement of water permeability, showing Pf values that exceeds their individual contribution. The expression pattern of both aquaporin subtypes in two cultivars with contrasting fruit firmness showed that the firmer cultivar (Camarosa) presents higher accumulation of FaPIP1 and FaPIP2 mRNAs during fruit ripening when compared with the softer cultivar (Toyonoka). In conclusion, not only FaPIP aquaporins showed an expression pattern associated with fruit firmness but also the enhancement of water transfers through the plasma membrane is coupled to the presence/absence of the co-expression of both subtypes.