Project description:Wild yeast and many clinical strains form complex, biofilm colonies, providing protection from desiccation, drugs and other stresses. Few transcriptomic studies have focused on sub-surface invasive “roots” due to the challenges of cell isolation from agar and subpopulation cross-contamination. Here we present, a first transcriptomic analysis via RNA sequencing of root and aerial cells, separated by a novel method. We identified 719 coding genes with upregulated root expression, mainly involved in ribosome structure/biogenesis, biosynthesis and translation and 529 loci/genes with upregulated aerial expression, mainly involved in meiosis/sporulation, stress defense and protein degradation; all indicating that aerial cells are resting and root cells are metabolically active cells. On the basis of 172 root-upregulated and 233 aerial-upregulated non-coding loci detected, anti-regulated gene/lncRNA pairs have been identified that may contribute to negative regulation of gene expression. Importantly, cells showing typical markers of “roots” correspond with cells embedded in extracellular matrix and cells showing typical markers of “aerial” parts with ECM-free cells.
Project description:When grown on solid substrates, different microorganisms often form colonies with very specific morphologies. Whereas the pioneers of microbiology often used colony morphology to discriminate between species and strains, the phenomenon has not received much recent attention. In this study, we use a genome-wide assay in the model yeast Saccharomyces cerevisiae to identify all genes that affect colony morphology. We show that several major signaling cascades, including the MAPK, TORC, SNF1 and RIM101 pathways play a role, indicating that morphological changes are a reaction to changing environments. Other genes that affect colony morphology are involved in protein sorting and epigenetic regulation. Interestingly, the screen reveals only few genes that are likely to play a direct role in establishing colony morphology, one notable exception being FLO11, a gene encoding a cell-surface adhesin that has already been implicated in colony morphology, biofilm formation, and invasive and pseudohyphal growth. Using a series of modified promoters to tune FLO11 expression, we confirm the central role of Flo11 and show that differences in FLO11 expression result in distinct colony morphologies. Together, our results provide a first comprehensive looks at the complex genetic network that underlies the diversity in the morphologies of yeast colonies.
Project description:When grown on solid substrates, different microorganisms often form colonies with very specific morphologies. Whereas the pioneers of microbiology often used colony morphology to discriminate between species and strains, the phenomenon has not received much recent attention. In this study, we use a genome-wide assay in the model yeast Saccharomyces cerevisiae to identify all genes that affect colony morphology. We show that several major signaling cascades, including the MAPK, TORC, SNF1 and RIM101 pathways play a role, indicating that morphological changes are a reaction to changing environments. Other genes that affect colony morphology are involved in protein sorting and epigenetic regulation. Interestingly, the screen reveals only few genes that are likely to play a direct role in establishing colony morphology, one notable exception being FLO11, a gene encoding a cell-surface adhesin that has already been implicated in colony morphology, biofilm formation, and invasive and pseudohyphal growth. Using a series of modified promoters to tune FLO11 expression, we confirm the central role of Flo11 and show that differences in FLO11 expression result in distinct colony morphologies. Together, our results provide a first comprehensive looks at the complex genetic network that underlies the diversity in the morphologies of yeast colonies. Microarrays were used to measure gene expression between WT and FLO11 mutants in both liquid and solid medium to assess which genes induce altered colony morphology through FLO11.
Project description:Effect of FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c.
Project description:Second fermentation in a bottle supposes such specific conditions that undergo yeasts to a set of stress situations like high ethanol, low nitrogen, low pH or sub-optimal temperature. Also, yeast have to grow until 1 or 2 generations and ferment all sugar available while they resist increasing CO2 pressure produced along with fermentation. Because of this, yeast for second fermentation must be selected depending on different technological criteria such as resistance to ethanol, pressure, high flocculation capacity, and good autolytic and foaming properties. All of these stress factors appear sequentially or simultaneously, and their superposition could amplify their inhibitory effects over yeast growth. Considering all of the above, it has supposed interesting to characterize the adaptive response of commercial yeast strain EC1118 during second-fermentation experiments under oenological/industrial conditions by transcriptomic profiling. We have pointed ethanol as the most relevant environmental condition in the induction of genes involved in respiratory metabolism, oxidative stress, autophagy, vacuolar and peroxisomal function, after comparison between time-course transcriptomic analysis in alcoholic fermentation and transcriptomic profiling in second fermentation. Other examples of parallelism include overexpression of cellular homeostasis and sugar metabolism genes. Finally, this study brings out the role of low-temperature on yeast physiology during second-fermentation.
Project description:In this study, we performed RNAseq of PolyA enriched RNA from budding yeast cells that were either wild-type or having the mcd1-1 mutation. By obtaining over 200 million reads of sequences from PolyA RNA, we mapped greater than 30 million reads per sample to the yeast genome (S288C R64-2-1_20150113)and generated transcriptomic profiles of wild-type and mcd1-1 mutant cells. Comparison of the wild type and mutant transcriptomes revealed that 11.44% genes were upregulated, 4.99% were downregulated and 83.57% were unaffected in the mutant with a fold change ≥2.0 and Padj value <0.05. When the alterations in gene expression were analyzed with respect to chromosomal position, preferential derepression of subtelomeric (located within 20 kilo bases from the chromosome end) genes was observed in the mutant.