Filamentous growth in wine yeast: signal triggering and genetic factors involved

Identifier:  TDX:2716

Handle: https://hdl.handle.net/20.500.11797/TDX2716

Authors:  González Sánchez, Beatriz

Abstract:
Compounds derived from aromatic amino acid, which are naturally present in grape must, are transformed by yeast metabolism. Here, we study the production of these compounds in synthetic must with different nutrient content by wine yeast species. The bioconversion of these compounds depends on the nutrients and precursors available in the must. The results showed that the synthesis pattern of tryptophol, phenylethanol and tyrosol is controlled by nutrient availability. We also studied the effect of these compounds and other derived from aromatic amino acids in the cell growth and morphology. Our results indicate these compounds are able to affect growth and cell morphology in most tested species. Again, this effect depends on nutrient availability. We also studied filamentous growth in wine yeast. Consequently, we found that ethanol-inducible filamentous growth is controlled by the RTG pathway, which requires polarisome function and occurs by a Flo11p-dependent transcriptional induction. Moreover, a QTL approach was used to unravel genetic basis involved in filamentous growth. Through the analysis of the progeny generating by crossing parental strains with opposite phenotype, seven genes were identified as candidates to induce filamentous growth in natural wine strains: MEP2, NGR1, PHD1, SRV2, ELM1, SER33, YNL234W. All of them are involved in regulatory sensing pathways.