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Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

Elleuche S, Pöggeler S - PLoS ONE (2009)

Bottom Line: No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile.Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant.The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany.

ABSTRACT
Carbon dioxide (CO(2)) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3) (-)) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions.

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Related in: MedlinePlus

Vegetative growth rate of S. macrospora wild type and cas mutant strains in ambient air and at elevated CO2.Strains were grown for 3 days on solid BMM either in ambient air (black bars) or at 5% CO2 (white bars). Growth rate of wild type in ambient air was defined as 100%. Growth rates shown are averages from nine measurements of three independent experiments. Error bars are given as indicated.
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pone-0005177-g006: Vegetative growth rate of S. macrospora wild type and cas mutant strains in ambient air and at elevated CO2.Strains were grown for 3 days on solid BMM either in ambient air (black bars) or at 5% CO2 (white bars). Growth rate of wild type in ambient air was defined as 100%. Growth rates shown are averages from nine measurements of three independent experiments. Error bars are given as indicated.

Mentions: The characterization of Δcas1 and Δcas3 single knock-out mutants revealed no obvious phenotypic changes compared to the wild type. Almost no alterations in vegetative growth behavior were detectable, when measuring the growth rate under ambient air conditions (Figure 6). Only Δcas1 showed a 14% elevated growth velocity at 5% CO2. Furthermore, neither Δcas1 nor Δcas3 displayed irregularities in mycelial morphology or the formation of sexual reproductive structures (Figure 7). When compared to the wild type or single knock-out strains, the Δcas1/3 double deletion strain also showed no changes in vegetative morphology or reproductive structures. Interestingly, similar to Δcas1, Δcas3 and Δcas1/3 sexual reproduction of the S. macrospora wild type was not affected by high CO2 concentrations, as recently reported for the basidiomycete C. neoformans [16].


Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

Elleuche S, Pöggeler S - PLoS ONE (2009)

Vegetative growth rate of S. macrospora wild type and cas mutant strains in ambient air and at elevated CO2.Strains were grown for 3 days on solid BMM either in ambient air (black bars) or at 5% CO2 (white bars). Growth rate of wild type in ambient air was defined as 100%. Growth rates shown are averages from nine measurements of three independent experiments. Error bars are given as indicated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2664464&req=5

pone-0005177-g006: Vegetative growth rate of S. macrospora wild type and cas mutant strains in ambient air and at elevated CO2.Strains were grown for 3 days on solid BMM either in ambient air (black bars) or at 5% CO2 (white bars). Growth rate of wild type in ambient air was defined as 100%. Growth rates shown are averages from nine measurements of three independent experiments. Error bars are given as indicated.
Mentions: The characterization of Δcas1 and Δcas3 single knock-out mutants revealed no obvious phenotypic changes compared to the wild type. Almost no alterations in vegetative growth behavior were detectable, when measuring the growth rate under ambient air conditions (Figure 6). Only Δcas1 showed a 14% elevated growth velocity at 5% CO2. Furthermore, neither Δcas1 nor Δcas3 displayed irregularities in mycelial morphology or the formation of sexual reproductive structures (Figure 7). When compared to the wild type or single knock-out strains, the Δcas1/3 double deletion strain also showed no changes in vegetative morphology or reproductive structures. Interestingly, similar to Δcas1, Δcas3 and Δcas1/3 sexual reproduction of the S. macrospora wild type was not affected by high CO2 concentrations, as recently reported for the basidiomycete C. neoformans [16].

Bottom Line: No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile.Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant.The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbiology and Genetics, Department of Genetics of Eukaryotic Microorganisms, Georg-August University, Göttingen, Germany.

ABSTRACT
Carbon dioxide (CO(2)) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3) (-)) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions.

Show MeSH
Related in: MedlinePlus