UV-C treatment on strawberry fruit: effect on gene expression in different tissues

ROSLI, HERNÁN GUILLERMO; POMBO, MARINA ALEJANDRA; CIVELLO, PEDRO MARCOS; FOLTA, KEVIN M.

Crystal River, Florida, EEUU

Workshop; 20th Annual PMCB Workshop; 2009

PMCB Universidad de Florida

UV-C radiation of fruit has been tested to control postharvest diseases and delay some ripening processes. Nevertheless, there is little information concerning the mechanism by which beneficial UV-C induced changes occur. This work tests the effect of UV-C radiationon gene expression in different fruit tissue levels. Ripe strawberry fruits (cv. Strawberry Festival) were irradiated with UV-C (4.1 kJ m-2). Control fruit received identical treatment with a Plexiglass filter. After treated, fruit were stored at 24 °C under white light, and samples from control (C) and treated (T) were taken at different time points. The expression of an expansin gene (FaExp2) was analyzed by Northern-blot. At 4 h the expression was found to be higher in control fruit, consequently this time point was chosenfor further analysis. This difference was confirmed by qPCR, but no significant change could be detected for pectin methylesterase (FaPE1, AY324809) and beta-1,3-glucanase 2-1 (FaBG2-1, AY170375). Consequently, fruit were irradiated, but after 4 h of storage in the dark, different tissues were dissected (cortex and pith) and gene expression assessed separately. In this case, differences could be detected, mainly in the cortical region of the fruit, being not evident or less marked in the pith. These results suggest a certain degree of localization of fruit response to UV-C radiation.