Background: Saccharomyces cerevisiae
is the main microorganism responsible for alcoholic fermentation. In this
process, the consumption of nitrogen is of great importance since it is found in limiting quantities and its
deficiency produces sluggish and/or stuck fermentations generating large economic losses in the wine-making
industry. In a previous work we compared the transcriptional profiles between genetically related strains with
differences in nitrogen consumption, detecting genes with differential expression that could be associated to
the differences in the levels of nitrogen consumed. One of the genes identified was
ICY1. With the aim of
confirming this observation, in the present work we evaluated the consumption of ammonium during the
fermentation of strains that have deleted or overexpressed this gene.
Results: Our results confirm the effect of
ICY1 on nitrogen uptake by evaluating its expression in wine yeasts
during the first stages of fermentation under low (MS60) and normal (MS300) assimilable nitrogen. Our results
show that the mRNA levels of
ICY1 diminish when the amount of assimilable nitrogen is low. Furthermore, we
constructed strains derived from the industrial strain EC1118 as a null mutant in this gene as well as one that
overexpressed it.
Conclusions: Our results suggest that the expression of
ICY1 is regulated by theamount of nitrogen available in the
must and it is involved in the consumption of ammonium, given the increase in the consumption of this nitrogen
source observed in the null mutant strain.
