ROS signaling mediates aeration-dependent thermotolerance in Kluyveromyces marxianus for high-temperature xylitol production.

Proteomic Insights into Salt-Stress Tolerance in Zygosaccharomyces rouxii Revealed by Data-Independent Acquisition Mass Spectrometry.

Under severe stress, GO and KEGG enrichment consistently revealed the reinforcement of central carbon and energy metabolism, peroxisome-associated fatty acid turnover, oxidoreductase/redox activities, and translation and nucleotide metabolic pathways.

Regulatory Effects and Mechanisms of Dissolved Oxygen on Xylitol Biosynthesis from Glucose by Zygoascus hellenicus B11

Transcriptomic insights into exogenous fatty acid-enhanced halotolerance in Zygosaccharomyces rouxii.

BACKGROUND High salinity restricts microbial growth during brine-based food fermentation. Although exogenous unsaturated fatty acids improve the salt tolerance of Zygosaccharomyces rouxii, the associated transcriptional mechanisms remain unclear. This study investigated the transcriptomic response of Z. rouxii CGMCC 3791 to palmitoleic acid (C16:1) under high salt conditions. RESULTS Cells were cultured in yeast extract peptone dextrose (YPD) containing 120 g L-1 NaCl, with or without 20 μg mL-1 C16:1. They were analyzed by RNA sequencing. Principal component analysis clearly separated the two treatments. Using q < 0.05 and |log2 fold change| > 1, 23 differentially expressed genes were identified - three upregulated and 20 downregulated. INO1, MLS1, POX1, MEP2, and SOD5 were among the major responsive genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that peroxisome-associated functions, lipid metabolism, oxidative stress responses, nitrogen utilization, and mitogen-activated protein kinase (MAPK) signaling were the principal C16:1-responsive processes. CONCLUSION Exogenous C16:1 elicited a focused transcriptional adjustment rather than broad transcriptome-wide reprogramming in salt-stressed Z. rouxii. The results indicated that peroxisome-linked lipid processes and redox regulation were candidate mechanisms underlying fatty-acid-associated halotolerance and provided targets for improving the robustness of high-salt food fermentation. © 2026 Society of Chemical Industry.

Heat stress-induced degradation of glutamine synthetase rebalances central carbon-nitrogen metabolism and promotes thermotolerance in Ganoderma lucidum

ABSTRACT Thermotolerance is fundamental to fungal ecology and survival. Although heat stress triggers extensive metabolic reprogramming, the function of these changes for thermotolerance has remained poorly understood. Here, we identify glutamine synthetase (GS), a central nitrogen metabolism enzyme, as a critical determinant of thermotolerance in Ganoderma lucidum. Silencing of gs significantly enhanced fungal tolerance under heat stress and reduced the relative inhibition rate of mycelial growth to 9.71%, compared with 20.7% in the wild-type (WT) strain. Heat stress also increased reactive oxygen species and H₂O₂ levels by 1.49- and 1.38-fold in the WT strain, whereas the increments were markedly lower in gs-silenced strains. Subsequently, under heat stress, α-ketoglutarate contents in WT increased by 1.49-fold. Inhibition of GS further increased the accumulation, which was achieved by upregulating glutamate dehydrogenase to promote the conversion of glutamate to α-ketoglutarate. This metabolic response was correlated with the generation of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NADH). Moreover, under heat stress, the level of GS protein in WT strains decreased by 29.0%, compared with that under normal conditions, due to accelerated degradation via the 26S proteasome. Our findings reveal that a ubiquitin-dependent signal instantaneously rebalances central carbon-nitrogen metabolism, offering a direct and rapid link between central metabolism and thermotolerance in fungi. IMPORTANCE Understanding how organisms adapt to heat stress is of increasing urgency in the context of global warming. While the roles of heat-shock proteins and antioxidant systems are well established, how microbes actively reprogram central metabolism to survive thermal challenge remains a fundamental, unanswered question. This study reveals that the central nitrogen metabolism enzyme glutamine synthetase (GS) is degraded by the ubiquitin-proteasome system and that this degradation acts as a metabolic switch to enhance thermotolerance in Ganoderma lucidum. We discovered that heat stress induces ubiquitin-proteasome system-dependent GS degradation, leading to redirected central nitrogen flux that elevates α-ketoglutarate content. This metabolic shift boosts ATP and NADH production. In summary, our findings represent a significant advance beyond classical protein chaperone systems and reactive oxygen species-scavenging systems, highlighting a direct and rapid link between metabolic flux and thermotolerance. Understanding how organisms adapt to heat stress is of increasing urgency in the context of global warming. While the roles of heat-shock proteins and antioxidant systems are well established, how microbes actively reprogram central metabolism to survive thermal challenge remains a fundamental, unanswered question. This study reveals that the central nitrogen metabolism enzyme glutamine synthetase (GS) is degraded by the ubiquitin-proteasome system and that this degradation acts as a metabolic switch to enhance thermotolerance in Ganoderma lucidum. We discovered that heat stress induces ubiquitin-proteasome system-dependent GS degradation, leading to redirected central nitrogen flux that elevates α-ketoglutarate content. This metabolic shift boosts ATP and NADH production. In summary, our findings represent a significant advance beyond classical protein chaperone systems and reactive oxygen species-scavenging systems, highlighting a direct and rapid link between metabolic flux and thermotolerance.

Increased tolerance to biomass-derived inhibitors by deletion of the transcriptional regulator mraZ in Cupriavidus necator H16.

Findings indicate that deletion of the transcriptional regulator mraZ is an effective strategy to enhance stress tolerance and improve bioproduction.

Comparative Genomic and Transcriptomic Analyses of 60Co-Mutagenized Scheffersomyces stipitis Strains: Identification of Candidate Genes Associated with High-Ethanol-Producing Xylose-to-Ethanol Fermentation

60 candidate key genes associated with high xylose-to-ethanol yield in S. stipitis are identified, predominantly involved in the cell cycle pathway, including CDC15 and PHO81.