Strawberry fruit ripening: fueling PIP aquaporin contribution

MERCEDES MARQUEZ; AGUSTIN YANEFF; VICTORIA VITALI; KARINA ALLEVA; GABRIELA AMODEO

Workshop; PanAmerican Plant Membrane Biology Workshop 2015 San Pedro de Atacama, Chile, Junio 1-5 de 2015; 2015

Organizing Committe PAPMBM

Fruit ripening includes a set of physiological andbiochemical events that finally lead changes in fruit color, flavor, aroma andtexture. During the different stages, a complex hydraulic phenomenon must takeplace in order to sustain processes such as cell division, cell expansion aswell as loss of turgor. It is therefore necessary to understand not only waterflows through the fruit vascular system but also include in the discussion thecontribution of transcellular water movements. Strawberry is considered a non-climacteric fleshyfruit characterized by a rapid loss of firmness during ripening. Here wepresent a comprehensive study of strawberry fruit ripening, contemplatinganatomical, physiological and molecular aspects focusing in water hydraulics asa whole. Our results show that although there is a clear reduction in xylemwater transport in the later stages (100% Red) neither interruption of thephysical continuity nor loss of functionality of the xylem vessels in thestrawberry fruit is observed. When analyzing in particular the cell-to-cellwater pathways we found that plasma membrane aquaporins (FaPIP1 and FaPIP2) havean expression pattern associated with different stages of ripening. Using anheterologous expression system we characterized the intrinsic water propertiesof two aquaporins FaPIP1;1 and FaPIP2;1 and show regulation by co-expression(increasing water permeability) and cellular acidification (decreasing waterpermeability). Our results are in agreement with revisiting the role of the cell-to-cellwater pathways to broad perspectives in fruit physiology and biotechnology.