期刊
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
卷 87, 期 9, 页码 -出版社
AMER SOC MICROBIOLOGY
DOI: 10.1128/AEM.01321-20
关键词
Aspergillus nidulans; autolytic cell wall degradation; glutathione degradation; dug genes; oxidative stress tolerance; sterigmatocystin production; transcriptomics
资金
- European Union
- European Social Fund [EFOP-3.6.1-16-2016-00022]
- National Research, Development and Innovation Office (Hungary) [K112181, K119494, NN125671, K131767]
- Thematic Excellence Program of the Ministry for Innovation and Technology in Hungary [TKP2020-IKA-04]
- National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch project [1009695]
Glutathione (GSH) plays a crucial role in redox regulation in fungi, affecting oxidative stress defense, protein secretion, secondary metabolite production, and sexual and asexual differentiations. Even slight changes in GSH levels can significantly disturb fungal homeostasis, highlighting the importance of understanding GSH metabolism for biotechnological applications.
Glutathione (GSH) is an abundant tripeptide that plays a crucial role in shielding cellular macromolecules from various reactive oxygen and nitrogen spedes in fungi. Understanding GSH metabolism is of vital importance for deciphering redox regulation in these microorganisms. In the present study, to better understand the GSH metabolism in filamentous fungi, we investigated functions of the dugB and dugC genes in the model fungus Aspergillus nidulans. These genes are orthologues of dug2 and dug3, which are involved in cytosolic GSH degradation in Saccharomyces cerevisiae. The deletion of dugB, dugC, or both resulted in a moderate increase in the GSH content in mycelia grown on glucose, reduced conidium production, and disturbed sexual development. In agreement with these observations, transcriptome data showed that genes encoding mitogen-activated protein (MAP) kinase pathway elements (e.g., steC, sskB, hogA, and mkkA) or regulatory proteins of conidiogenesis and sexual differentiation (e.g., flbA, flbC, flbE, nosA, rosA, nsdC, and nsdD) were downregulated in the Delta dugB Delta dugC mutant. Deletion of dugB and/or dugC slowed the depletion of GSH pools during carbon starvation. It also reduced accumulation of reactive oxygen species and decreased autolytic cell wall degradation and enzyme secretion but increased sterigmatocystin formation. Transcriptome data demonstrated that enzyme secretions-in contrast to mycotoxin production-were controlled at the posttranscriptional level. We suggest that GSH connects starvation and redox regulation to each other: cells utilize GSH as a stored carbon source during starvation. The reduction of GSH content alters the redox state, activating regulatory pathways responsible for carbon starvation stress responses. IMPORTANCE Glutathione (GSH) is a widely distributed tripeptide in both eukaryotes and prokaryotes. Owing to its very low redox potential, antioxidative character, and high intracellular concentration, GSH profoundly shapes the redox status of cells. Our observations suggest that GSH metabolism and/or the redox status of cells plays a determinative role in several important aspects of fungal life, including oxidative stress defense, protein secretion, and secondary metabolite production (including mycotoxin formation), as well as sexual and asexual differentiations. We demonstrated that even a slightly elevated GSH level can substantially disturb the homeostasis of fungi. This information could be important for development of new GSH-producing strains or for any biotechnologically relevant processes where the GSH content, antioxidant capacity, or oxidative stress tolerance of a fungal strain is manipulated.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据