Studio dell'aggregazione cellulare in ceppi vinari diSaccharomyces cerevisiae

Among the different genes that regulate biofilm formation in strains of Saccharomyces cerevisiae, FLO11 plays a fundamental role. In a previous work we showed that FLO11 is required for air-liquid interfacial biofilm and we proposed a model for biofilm formation based on the ability of cells to entrap carbon dioxide, providing buoyancy. FLO11 belongs to the adhesin gene family, including FLO1, FLO5, FLO9 and FLO10 and the protein encoded by each gene has considerable sequence identity with other family members. Other authors showed that the gene size of FLO1 and the number of intragenic repeat sequences creates quantitative alteration in adhesion, flocculation and biofilm formation phenotypes. In this work, in order to observe correlations between FLO11 gene size and cell adhesion, we analysed several Sardinian biofilm forming strains of Saccharomyces cerevisiae (flor strains) with different genetic backgrounds. We amplified FLO11 and its intragenic repeat sequences in all the analysed strains and we correlated the lengths with the following phenotypes: biofilm formation, adhesion to plastic, mat formation and idrophobicity. Interestingly, we observed a variable correlation between FLO11 gene size and the described phenotypes. In particular, different strains showed differences in adhesion to plastic and biofilm formation or idrophobicity and biofilm formation independently of the expansion and contraction in FLO11 lenght.