Identification of water channels in strawberry fruit that modify their pattern expression during ripening

GABRIELA AMODEO; PAULA MUT; CLAUDIA BUSTAMANTE; KARINA ALLEVA; MOIRA SUTKA; GUSTAVO MARTINEZ; MARCOS CIVELLO

Bruselas, Belgica

Congreso; The 4th International 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 is consequently crucial in establishing strategies to extend post harvesting lifetime of this commercial fruit. It is known that fruit softening is partially due to cell wall degradation, the enzymes involved in the process and is also affected by temperature treatments. However, very little is known about the role of turgence or the pathways involved in water movement and how are they involved in this process. Hence, the aim of our proposal is focused in identifying the presence of strawberry water channels and find out if they might have a putative role in fruit softening. A cDNA library constructed from ripe strawberry fruit (cv Chandler), screened using a heterologous probe from tomato allowed us to isolate a 1.2Kb fragment (FaMIP). The fragment was completely sequenced using T3, T7 and internal primers, showing its deducted sequence protein a high homology to the plant aquaporin family. Preliminary results showed low water permeability when FaMIP was expressed in Xenopus oocytes. On the other hand, fruits harvested at different stages of ripening (small green, white, 25%Red, 50%Red and Ripe stages) were collected and immediately frozen to latter perform total RNA isolation of the fractions. Northern blot studies from these samples showed clearly that FaMIP modifies its pattern expression during strawberry ripening. We here report that proteins that are homologues to water channels are present in strawberry fruit and show modification of their expression pattern during strawberry ripening.