, 2005), invasive growth and pseudohyphal formation (Lambrechts et al., 1996; Lo & Dranginis, 1996), flor formation (Ishigami et al., 2004; Zara et al., 2005; Fidalgo et al., 2006) and adhesion to biotic Cytoskeletal Signaling inhibitor and

abiotic surfaces (Verstrepen et al., 2004; Verstrepen & Klis, 2006). In addition, the flocculent phenotype displayed by both BM45-F11H and VIN13-F11H transgenic strains was not inhibited in the presence of either glucose or mannose. Because NewFlo-type flocculation is inhibited by both mannose and glucose, while Flo1-type flocculation is exclusively inhibited by mannose (Stratford & Assinder, 1991), this result clearly demonstrates that FLO11 transgenic wine yeast-encoded flocculins exhibit neither Flo1-type nor NewFlo-type flocculation mechanisms. It can be suggested that the flocculent phenotype of BM45-F11H and VIN13-F11H

transformants may at least in part belong to a third group named MI, which is insensitive to mannose (and glucose), and independent of Ca2+ ions (Masy et al., 1992). Masy and colleagues postulated that flocculation in such strains could be produced by hydrophobic interactions or other specific interactions not involving mannans. While Stratford (1992) suggested that MI probably results from very low specificity to monosaccharides because lectins may have much greater affinity for tri- or polysaccharides than for simple sugars. Therefore, it is most likely that the flocculation mechanism of these FLO11-based transgenic wine

yeast strains would deviate from the widely accepted lectin selleckchem hypothesis that was originally proposed by Miki et al. (1982). Importantly, this industrially relevant FLO11-mediated flocculation phenotype that was observed in Merlot fermentations does not appear to be red grape varietal dependent as it was also evident in fermentations using Cabernet Sauvignon and Petit Verdot red grape varietals. This study clearly demonstrates for the first time that it is indeed possible to harness the innate Urease dominant FLO11 gene ORF of nonflocculent commercial wine yeast strains using of self-cloning promoter replacement cassettes to yield conditionally flocculent wine yeast strains with oenological properties that are superior to their parental wild-type strains. From the data generated thus far, further investigation is required to have a complete and detailed understanding of flocculation mechanism that underpins this biotechnologically important and interesting FLO11-mediated adhesion phenotype. This work was financially supported by the National Research Foundation (NRF) and the South African Wine Industry (Winetech). Table S1. Volatile components in wines produced from Merlot grape must. Table S2. FT-IR analysis of oenological factors of Merlot red wines. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials supplied by the authors.