Characterization of gfdb, putatively encoding a glycerol 3-phosphate dehydrogenase in Aspergillus nidulans

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Abstract

The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB. Unexpectedly, ΔgfdB strains showed oxidative stress sensitivity in the presence of a series of well-known oxidants including tert-butyl-hydroperoxide (tBOOH), diamide as well as hydrogen peroxide. Moderate sensitivity of the mutant towards the cell wall stress inducing agent CongoRed was also observed. Hence, both Gfd isoenzymes contributed to the environmental stress defence of the fungus but their functions were stress-type-specific. Furthermore, the specific activities of certain antioxidant enzymes, like catalase and glutathione peroxidase, were lower in ΔgfdB hyphae than those recorded in the control strain. As a consequence, mycelia from ΔgfdB cultures accumulated reactive species at higher levels than the control. On the other hand, the specific glutathione reductase activity was higher in the mutant, most likely to compensate for the elevated intracellular oxidative species concentrations. Nevertheless, the efficient control of reactive species failed in ΔgfdB cultures, which resulted in reduced viability and, concomitantly, early onset of programmed cell death in mutant hyphae. Inactivation of gfdB brought about higher mannitol accumulation in mycelia meanwhile the erythritol production was not disturbed in unstressed cultures. After oxidative stress treatment with tBOOH, only mannitol was detected in both mutant and control mycelia and the accumulation of mannitol even intensified in the ΔgfdB strain.

Original languageEnglish
JournalFungal Biology
DOIs
Publication statusAccepted/In press - Jan 1 2019

Fingerprint

glycerol-3-phosphate dehydrogenase
Glycerolphosphate Dehydrogenase
Aspergillus nidulans
Mycelium
Mannitol
Hyphae
phosphate
mutants
mannitol
mycelium
Oxidative Stress
Fungi
Erythritol
Diamide
tert-Butylhydroperoxide
Glutathione Reductase
hyphae
Osmotic Pressure
Gene Deletion
Glutathione Peroxidase

Keywords

  • Alditol
  • Apoptosis
  • Filamentous fungus
  • Glycerol biosynthesis
  • Osmotic stress
  • Oxidative stress

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Infectious Diseases

Cite this

@article{8c72e78705124878b792dbd520430213,
title = "Characterization of gfdb, putatively encoding a glycerol 3-phosphate dehydrogenase in Aspergillus nidulans",
abstract = "The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB. Unexpectedly, ΔgfdB strains showed oxidative stress sensitivity in the presence of a series of well-known oxidants including tert-butyl-hydroperoxide (tBOOH), diamide as well as hydrogen peroxide. Moderate sensitivity of the mutant towards the cell wall stress inducing agent CongoRed was also observed. Hence, both Gfd isoenzymes contributed to the environmental stress defence of the fungus but their functions were stress-type-specific. Furthermore, the specific activities of certain antioxidant enzymes, like catalase and glutathione peroxidase, were lower in ΔgfdB hyphae than those recorded in the control strain. As a consequence, mycelia from ΔgfdB cultures accumulated reactive species at higher levels than the control. On the other hand, the specific glutathione reductase activity was higher in the mutant, most likely to compensate for the elevated intracellular oxidative species concentrations. Nevertheless, the efficient control of reactive species failed in ΔgfdB cultures, which resulted in reduced viability and, concomitantly, early onset of programmed cell death in mutant hyphae. Inactivation of gfdB brought about higher mannitol accumulation in mycelia meanwhile the erythritol production was not disturbed in unstressed cultures. After oxidative stress treatment with tBOOH, only mannitol was detected in both mutant and control mycelia and the accumulation of mannitol even intensified in the ΔgfdB strain.",
keywords = "Alditol, Apoptosis, Filamentous fungus, Glycerol biosynthesis, Osmotic stress, Oxidative stress",
author = "Anita Kir{\'a}ly and Csaba H{\'a}mori and Gy{\"o}ngyi Gy{\'e}m{\'a}nt and K{\"o}v{\'e}r, {Katalin E.} and Istv{\'a}n P{\'o}csi and {\'E}va Leiter",
year = "2019",
month = "1",
day = "1",
doi = "10.1016/j.funbio.2019.09.011",
language = "English",
journal = "Fungal Biology",
issn = "1878-6146",
publisher = "Elsevier",

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TY - JOUR

T1 - Characterization of gfdb, putatively encoding a glycerol 3-phosphate dehydrogenase in Aspergillus nidulans

AU - Király, Anita

AU - Hámori, Csaba

AU - Gyémánt, Gyöngyi

AU - Kövér, Katalin E.

AU - Pócsi, István

AU - Leiter, Éva

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB. Unexpectedly, ΔgfdB strains showed oxidative stress sensitivity in the presence of a series of well-known oxidants including tert-butyl-hydroperoxide (tBOOH), diamide as well as hydrogen peroxide. Moderate sensitivity of the mutant towards the cell wall stress inducing agent CongoRed was also observed. Hence, both Gfd isoenzymes contributed to the environmental stress defence of the fungus but their functions were stress-type-specific. Furthermore, the specific activities of certain antioxidant enzymes, like catalase and glutathione peroxidase, were lower in ΔgfdB hyphae than those recorded in the control strain. As a consequence, mycelia from ΔgfdB cultures accumulated reactive species at higher levels than the control. On the other hand, the specific glutathione reductase activity was higher in the mutant, most likely to compensate for the elevated intracellular oxidative species concentrations. Nevertheless, the efficient control of reactive species failed in ΔgfdB cultures, which resulted in reduced viability and, concomitantly, early onset of programmed cell death in mutant hyphae. Inactivation of gfdB brought about higher mannitol accumulation in mycelia meanwhile the erythritol production was not disturbed in unstressed cultures. After oxidative stress treatment with tBOOH, only mannitol was detected in both mutant and control mycelia and the accumulation of mannitol even intensified in the ΔgfdB strain.

AB - The genome of Aspergillus nidulans accommodates two glycerol 3-phosphate dehydrogenase genes, gfdA and gfdB. Previous studies confirmed that GfdA is involved in the osmotic stress defence of the fungus. In this work, the physiological role of GfdB was characterized via the construction and functional characterization of the gene deletion mutant ΔgfdB. Unexpectedly, ΔgfdB strains showed oxidative stress sensitivity in the presence of a series of well-known oxidants including tert-butyl-hydroperoxide (tBOOH), diamide as well as hydrogen peroxide. Moderate sensitivity of the mutant towards the cell wall stress inducing agent CongoRed was also observed. Hence, both Gfd isoenzymes contributed to the environmental stress defence of the fungus but their functions were stress-type-specific. Furthermore, the specific activities of certain antioxidant enzymes, like catalase and glutathione peroxidase, were lower in ΔgfdB hyphae than those recorded in the control strain. As a consequence, mycelia from ΔgfdB cultures accumulated reactive species at higher levels than the control. On the other hand, the specific glutathione reductase activity was higher in the mutant, most likely to compensate for the elevated intracellular oxidative species concentrations. Nevertheless, the efficient control of reactive species failed in ΔgfdB cultures, which resulted in reduced viability and, concomitantly, early onset of programmed cell death in mutant hyphae. Inactivation of gfdB brought about higher mannitol accumulation in mycelia meanwhile the erythritol production was not disturbed in unstressed cultures. After oxidative stress treatment with tBOOH, only mannitol was detected in both mutant and control mycelia and the accumulation of mannitol even intensified in the ΔgfdB strain.

KW - Alditol

KW - Apoptosis

KW - Filamentous fungus

KW - Glycerol biosynthesis

KW - Osmotic stress

KW - Oxidative stress

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U2 - 10.1016/j.funbio.2019.09.011

DO - 10.1016/j.funbio.2019.09.011

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JO - Fungal Biology

JF - Fungal Biology

SN - 1878-6146

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