Long-range order and short-range disorder in Saccharomyces cerevisiae biofilm

Biofilm, a colony forming cooperative response of microorganisms under environmental stress, is a major concern for food safety, water safety and drug resistance. Most current works focus on controlling biofilm growth by targeting single genes. Here, the authors investigated transcriptome-wide expressions of the yeast Saccharomyces cerevisiae biofilm in wildtype, and six previously identified biofilm regulating overexpression strains. Using statistical distributions for low expression filter (TPM > 5), Pearson auto- and cross-correlations reveal a strong transcriptome-wide invariance among all genotypes. The 50 highly expressed genes, however, differ significantly between the genotypes. Principal components analysis shows the global similarity between most overexpression strains. Thus, though single overexpression strains may show significant favourable local and acute expression changes (short-range disorder), the almost unperturbed global and collective structure between the genotypes indicate gradual adaptive response converging to original stable biofilm states (long-range order). Hierarchical clustering and gene ontology show 11 groups of local (e.g. mitochondria processes, amine and nucleotide metabolic processes) and 6 groups of global (e.g. transcription, translation and cell cycle) processes for all genotypes. The overall data indicate that there is a strong global regulatory structure that keeps the overall biofilm stable in all investigated strains.