The cell wall and the response and tolerance to stresses of biotechnological relevance in yeasts

Abstract

In industrial settings and processes, yeasts may face multiple adverse environmental conditions. These include exposure to non-optimal temperatures or pH, osmotic stress, and deleterious concentrations of diverse inhibitory compounds. These toxic chemicals may result from the desired accumulation of added-value bio-products, yeast metabolism, or be present or derive from the pre-treatment of feedstocks, as in lignocellulosic biomass hydrolysates. Adaptation and tolerance to industrially relevant stress factors involve highly complex and coordinated molecular mechanisms occurring in the yeast cell with repercussions on the performance and economy of bioprocesses, or on the microbiological stability and conservation of foods, beverages, and other goods. To sense, survive, and adapt to different stresses, yeasts rely on a network of signaling pathways to modulate the global transcriptional response and elicit coordinated changes in the cell. These pathways cooperate and tightly regulate the composition, organization and biophysical properties of the cell wall. The intricacy of the underlying regulatory networks reflects the major role of the cell wall as the first line of defense against a wide range of environmental stresses. However, the involvement of cell wall in the adaptation and tolerance of yeasts to multiple stresses of biotechnological relevance has not received the deserved attention. This article provides an overview of the molecular mechanisms involved in fine-tuning cell wall physicochemical properties during the stress response of Saccharomyces cerevisiae and their implication in stress tolerance. The available information for non-conventional yeast species is also included. These non-Saccharomyces species have recently been on the focus of very active research to better explore or control their biotechnological potential envisaging the transition to a sustainable circular bioeconomy.

Mechanisms of Antioxidant Dipeptides Enhancing Ethanol-Oxidation Cross-Stress Tolerance in Lager Yeast: Roles of the Cell Wall and Membrane

“…Compared to the control, antioxidant dipeptides supplementation decreased the release of intracellular nucleic acid and protein, indicating that antioxidant dipeptides could decrease the cell wall damage caused by ethanol-oxidation cross-stress. Several studies have also demonstrated that the increase in CWI is essential for yeast survival under external stress. ,, In conclusion, the addition of antioxidant dipeptides under ethanol-oxidation cross-stress induced cell wall reshaping, improving cell wall rigidity and integrity, further protecting cells against multipressure.…”

“…Effects of antioxidant dipeptide supplementation on the yeast cell wall and membrane-related regulatory genes under ethanol-oxidation cross-stress. Schematic route (A): The external environment stress could trigger the response of the CWI pathway sensors, namely Wsc1–3, Mid2, and Mtl1 . These sensors interact with the guanine nucleotide exchange factor (GEF) Rom2 activating the small GTPase Rho1.…”

“…As an essential structure of yeast, cell wall is the first barrier against external stresses . The main ways of cell wall responding to environmental stresses are cell wall remodeling and signal pathway regulation . Under environmental stresses, cell wall components are remodeled, and the expression of genes related to cross-linking also changes that enhances the cross-linking structure .…”

Cross-Talk and Multiple Control of Target of Rapamycin (TOR) in Sclerotinia sclerotiorum

“…The composition and thickness of the cell wall changes when cells encounter different environmental stresses and, the cell wall integrity (CWI) pathway is tightly regulated in response to different signaling pathways ( 23 , 24 ). The CWI pathway is activated through Slg1/Wsc1, Wsc2, Wsc3, Mid2, and Mtl1, which can couple with Rho1 and activate the MAPK cascade (Pkc, Bck1, Mkk1, and Slt2) ( 25 – 27 ). SsTOR -silenced strains are not sensitive to cell wall inhibitors and the mycelium is denser than the wild type.…”

The NPR/Hal family of protein kinases in yeasts: biological role, phylogeny and regulation under environmental challenges

“…Hrk1 was shown to mediate the phosphorylation levels of 40% of membrane-associated acetic acid-responsive proteins [96] . One important mechanism of tolerance to weak acids is the remodelling of the cell wall, and plasma membrane [103] , [104] , [105] , [106] . Increasing the synthesis of sphingolipids has been proposed to enhance the tolerance to acetic acid in S. cerevisiae based on the observed increase in sphingolipids in this yeast species upon acetic acid stress [107] .…”