Abstract
In contrast to smooth colonies of laboratory strains, wild Saccharomyces cerevisiae strains form biofilm-like, strikingly structured colonies (Vachova et. al (2011) J Cell Biol. 194: 679-687; Stovicek et al (2010) Fungal Genet Biol 47: 1012-102) composed of aerial part and subsurface pseudohyphae. These biofilm colonies possess distinctive traits enabling them to better survive in unfavorable environments in the wild.
Specific features include formation of layers of resistant stationary-phase cells at the colony surface (some of them with active multidrug resistance transporters), the production of a protective low-permeable extracellular matrix (ECM) and the presence of adhesins (e.g. Flo11p).
ECM in internal colony parts plays a role of both a protective barrier and a nutrient pool for the cell progeny, adhesins help connecting cells in both aerial and subsurface colony parts and surface resistant cells protect colony population from external toxic compounds. In contrast to smooth colonies, where dividing cells localize to the margin and to the uppermost colony layer, dividing cells localize to the interior of biofilm colonies.