Ripening transition and storage environmental impact on sucrose
accumulation and associated responsive genes in strawberries
Abstract
To obtain the best taste of woodland strawberries (Fragaria vesca) at
the moment of consumption, it is essential to analyse the dynamics of
sugar accumulation during ripening transition stages and explore how to
control sucrose reserves after harvest. For this purpose, we analysed
the accumulation of major sugars, sucrose-related olygomers and the
expression of homologues genes involved in sucrose metabolism in
attached strawberries at different ripening stages and after harvest.
Measurements were taken during early and late phases of low temperature
storage (LT) with and without CO2 pretreatment and further shelf-life at
20 ºC (SL). Our results show an increase in major sugars and sucrose in
dark red (DR) strawberries associated with up-regulation of FvSPS1 and
down-regulation of FvVINV2. The CO2-treated fruit showed high levels of
sucrose, an FvSS1 up-regulation together with a modulation of homologues
of FvVINV. Moreover, fruit treated with CO2 during SL (LTC) revealed a
reduction in FvVINV homologue expression maintaining the sucrose
reserves. High amounts in fructose and myo-inositol at LTC were
observed, following a similar trend to that found in DR strawberries. We
suggest that CO2 pre-treatment promotes a carbohydrate conserving state
which has important implications for reducing weight loss and preserving
sweetness.