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Nancy P. Keller - One of the best experts on this subject based on the ideXlab platform.
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2 insight into fungal secondary metabolism from ten years of laea research
2016Co-Authors: Nancy P. KellerAbstract:In 2004, the protein LaeA was identified and characterized as a global regulator of secondary metabolism in the fungus Aspergillus nidulans. Since this initial report, LaeA has been further described as a member of the fungal-specific Velvet Complex, a transcriptional complex critical in linking morphological transitions with chemical output. Hence, LaeA and the other two members of the Velvet Complex, VeA and VelB, are not only key regulators of secondary metabolite production but also aSexual and Sexual Spore production. All three proteins are conserved in the Ascomycetes and possibly in the Basidiomycetes. Here, we will focus on LaeA-led studies contributing to our knowledge of regulation and synthesis of secondary metabolites in fungi.
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Oxylipins as developmental and host-fungal communication signals.
Trends in microbiology, 2007Co-Authors: Dimitrios I. Tsitsigiannis, Nancy P. KellerAbstract:Pathogenic microbes and their hosts have acquired complex signalling mechanisms to appraise themselves of the environmental milieu in the ongoing battle for survival. Several recent studies have implicated oxylipins as a novel class of host–microbe signalling molecules. Oxylipins represent a vast and diverse family of secondary metabolites that originate from the oxidation or further conversion of polyunsaturated fatty acids. Among the microbial oxylipins, the fungal oxylipins are best characterized and function as hormone-like signals that modulate the timing and balance between aSexual and Sexual Spore development in addition to toxin production. Coupled with other studies that implicate a role for fungal oxylipins in pathogenesis by Aspergillus and Candida spp., these results suggest that host and microbial oxylipins might interfere with the metabolism, perception or signalling processes of each other.
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Three putative oxylipin biosynthetic genes integrate Sexual and aSexual development in Aspergillus nidulans.
Microbiology, 2005Co-Authors: Dimitrios I. Tsitsigiannis, Terri M. Kowieski, Robert Zarnowski, Nancy P. KellerAbstract:Oxylipins called psi factors have been shown to alter the ratio of aSexual to Sexual sporulation in the filamentous fungus Aspergillus nidulans. Analysis of the A. nidulans genome has led to the identification of three fatty acid oxygenases (PpoA, PpoB and PpoC) predicted to produce psi factors. Here, it is reported that deletion of ppoB (ΔppoB) reduced production of the oleic-acid-derived oxylipin psiBβ and increased the ratio of aSexual to Sexual Spore development. Generation of the triple mutant ΔppoAΔppoBΔppoC resulted in a strain deficient in producing oleic- and linoleic-acid-derived 8′-hydroxy psi factor and caused increased and mis-scheduled activation of Sexual development. Changes in aSexual to Sexual Spore development were positively correlated to alterations in the expression of brlA and veA, respectively. PpoB and/or its products antagonistically mediate the expression levels of ppoA and ppoC, thus revealing regulatory feedback loops among these three genes. Phylogenetic analyses showed that ppo genes are present in both saprophytic and pathogenic Ascomycetes and Basidiomycetes, suggesting a conserved role for Ppo enzymes in the life cycle of fungi.
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Three putative oxylipin biosynthetic genes integrate Sexual and aSexual development in Aspergillus nidulans.
Microbiology (Reading England), 2005Co-Authors: Dimitrios I. Tsitsigiannis, Terri M. Kowieski, Robert Zarnowski, Nancy P. KellerAbstract:Oxylipins called psi factors have been shown to alter the ratio of aSexual to Sexual sporulation in the filamentous fungus Aspergillus nidulans. Analysis of the A. nidulans genome has led to the identification of three fatty acid oxygenases (PpoA, PpoB and PpoC) predicted to produce psi factors. Here, it is reported that deletion of ppoB (DeltappoB) reduced production of the oleic-acid-derived oxylipin psiBbeta and increased the ratio of aSexual to Sexual Spore development. Generation of the triple mutant Delta ppoA Delta ppoB Delta ppoC resulted in a strain deficient in producing oleic- and linoleic-acid-derived 8'-hydroxy psi factor and caused increased and mis-scheduled activation of Sexual development. Changes in aSexual to Sexual Spore development were positively correlated to alterations in the expression of brlA and veA, respectively. PpoB and/or its products antagonistically mediate the expression levels of ppoA and ppoC, thus revealing regulatory feedback loops among these three genes. Phylogenetic analyses showed that ppo genes are present in both saprophytic and pathogenic Ascomycetes and Basidiomycetes, suggesting a conserved role for Ppo enzymes in the life cycle of fungi.
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The lipid body protein, PpoA, coordinates Sexual and aSexual sporulation in Aspergillus nidulans.
The Journal of biological chemistry, 2003Co-Authors: Dimitrios I. Tsitsigiannis, Robert Zarnowski, Nancy P. KellerAbstract:The coexistence of Sexual and aSexual reproductive cycles within the same individual is a striking phenomenon in numerous fungi. In the fungus Aspergillus nidulans (teleomorph: Emericella nidulans) endogenous oxylipins, called psi factor, serve as hormone-like signals that modulate the timing and balance between Sexual and aSexual Spore development. Here, we report the identification of A. nidulans ppoA, encoding a putative fatty acid dioxygenase, involved in the biosynthesis of the linoleic acid derived oxylipin psiBalpha. PpoA is required for balancing anamorph and teleomorph development. Deletion of ppoA significantly reduced the level of psiBalpha and increased the ratio of aSexual to Sexual Spore numbers 4-fold. In contrast, forced expression of ppoA resulted in elevated levels of psiBalpha and decreased the ratio of aSexual to Sexual Spore numbers 6-fold. ppoA expression is mediated by two developmental regulators, VeA and the COP9 signalosome, such that ppoA transcript levels are correlated with the initiation of aSexual and Sexual fruiting body formation. PpoA localizes in lipid bodies in these tissues. These data support an important role for oxylipins in integrating mitotic and meiotic Spore development.
Jeffrey P Townsend - One of the best experts on this subject based on the ideXlab platform.
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Gene Expression Differences among Three Neurospora Species Reveal Genes Required for Sexual Reproduction in Neurospora crassa
2016Co-Authors: Nina A. Lehr, Zheng Wang, Frances Trail, David A. Hewitt, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression acros
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Gene expression differences among three Neurospora species reveal genes required for Sexual reproduction in Neurospora crassa.
PLOS ONE, 2014Co-Authors: Nina A. Lehr, David Hewitt, Francesc López-giráldez, Zheng Wang, Ning Li, Frances Trail, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression across developmental stages increased more in N. crassa relative to the other species. Then, in N. crassa, we characterized the phenotypes of fruiting bodies arising from crosses of homozygous knockout strains of the top genes. Eight N. crassa genes were found to be critical for the successful formation of perithecia. The absence of these genes in these crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora Sexual reproduction, which is also of great importance with regard to other multicellular ascomycetes, including perithecium-forming pathogens, such as Claviceps purpurea, Ophiostoma ulmi, and Glomerella graminicola.
Nina A. Lehr - One of the best experts on this subject based on the ideXlab platform.
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Gene Expression Differences among Three Neurospora Species Reveal Genes Required for Sexual Reproduction in Neurospora crassa
2016Co-Authors: Nina A. Lehr, Zheng Wang, Frances Trail, David A. Hewitt, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression acros
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Gene expression differences among three Neurospora species reveal genes required for Sexual reproduction in Neurospora crassa.
PLOS ONE, 2014Co-Authors: Nina A. Lehr, David Hewitt, Francesc López-giráldez, Zheng Wang, Ning Li, Frances Trail, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression across developmental stages increased more in N. crassa relative to the other species. Then, in N. crassa, we characterized the phenotypes of fruiting bodies arising from crosses of homozygous knockout strains of the top genes. Eight N. crassa genes were found to be critical for the successful formation of perithecia. The absence of these genes in these crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora Sexual reproduction, which is also of great importance with regard to other multicellular ascomycetes, including perithecium-forming pathogens, such as Claviceps purpurea, Ophiostoma ulmi, and Glomerella graminicola.
Dimitrios I. Tsitsigiannis - One of the best experts on this subject based on the ideXlab platform.
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Oxylipins as developmental and host-fungal communication signals.
Trends in microbiology, 2007Co-Authors: Dimitrios I. Tsitsigiannis, Nancy P. KellerAbstract:Pathogenic microbes and their hosts have acquired complex signalling mechanisms to appraise themselves of the environmental milieu in the ongoing battle for survival. Several recent studies have implicated oxylipins as a novel class of host–microbe signalling molecules. Oxylipins represent a vast and diverse family of secondary metabolites that originate from the oxidation or further conversion of polyunsaturated fatty acids. Among the microbial oxylipins, the fungal oxylipins are best characterized and function as hormone-like signals that modulate the timing and balance between aSexual and Sexual Spore development in addition to toxin production. Coupled with other studies that implicate a role for fungal oxylipins in pathogenesis by Aspergillus and Candida spp., these results suggest that host and microbial oxylipins might interfere with the metabolism, perception or signalling processes of each other.
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Three putative oxylipin biosynthetic genes integrate Sexual and aSexual development in Aspergillus nidulans.
Microbiology, 2005Co-Authors: Dimitrios I. Tsitsigiannis, Terri M. Kowieski, Robert Zarnowski, Nancy P. KellerAbstract:Oxylipins called psi factors have been shown to alter the ratio of aSexual to Sexual sporulation in the filamentous fungus Aspergillus nidulans. Analysis of the A. nidulans genome has led to the identification of three fatty acid oxygenases (PpoA, PpoB and PpoC) predicted to produce psi factors. Here, it is reported that deletion of ppoB (ΔppoB) reduced production of the oleic-acid-derived oxylipin psiBβ and increased the ratio of aSexual to Sexual Spore development. Generation of the triple mutant ΔppoAΔppoBΔppoC resulted in a strain deficient in producing oleic- and linoleic-acid-derived 8′-hydroxy psi factor and caused increased and mis-scheduled activation of Sexual development. Changes in aSexual to Sexual Spore development were positively correlated to alterations in the expression of brlA and veA, respectively. PpoB and/or its products antagonistically mediate the expression levels of ppoA and ppoC, thus revealing regulatory feedback loops among these three genes. Phylogenetic analyses showed that ppo genes are present in both saprophytic and pathogenic Ascomycetes and Basidiomycetes, suggesting a conserved role for Ppo enzymes in the life cycle of fungi.
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Three putative oxylipin biosynthetic genes integrate Sexual and aSexual development in Aspergillus nidulans.
Microbiology (Reading England), 2005Co-Authors: Dimitrios I. Tsitsigiannis, Terri M. Kowieski, Robert Zarnowski, Nancy P. KellerAbstract:Oxylipins called psi factors have been shown to alter the ratio of aSexual to Sexual sporulation in the filamentous fungus Aspergillus nidulans. Analysis of the A. nidulans genome has led to the identification of three fatty acid oxygenases (PpoA, PpoB and PpoC) predicted to produce psi factors. Here, it is reported that deletion of ppoB (DeltappoB) reduced production of the oleic-acid-derived oxylipin psiBbeta and increased the ratio of aSexual to Sexual Spore development. Generation of the triple mutant Delta ppoA Delta ppoB Delta ppoC resulted in a strain deficient in producing oleic- and linoleic-acid-derived 8'-hydroxy psi factor and caused increased and mis-scheduled activation of Sexual development. Changes in aSexual to Sexual Spore development were positively correlated to alterations in the expression of brlA and veA, respectively. PpoB and/or its products antagonistically mediate the expression levels of ppoA and ppoC, thus revealing regulatory feedback loops among these three genes. Phylogenetic analyses showed that ppo genes are present in both saprophytic and pathogenic Ascomycetes and Basidiomycetes, suggesting a conserved role for Ppo enzymes in the life cycle of fungi.
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The lipid body protein, PpoA, coordinates Sexual and aSexual sporulation in Aspergillus nidulans.
The Journal of biological chemistry, 2003Co-Authors: Dimitrios I. Tsitsigiannis, Robert Zarnowski, Nancy P. KellerAbstract:The coexistence of Sexual and aSexual reproductive cycles within the same individual is a striking phenomenon in numerous fungi. In the fungus Aspergillus nidulans (teleomorph: Emericella nidulans) endogenous oxylipins, called psi factor, serve as hormone-like signals that modulate the timing and balance between Sexual and aSexual Spore development. Here, we report the identification of A. nidulans ppoA, encoding a putative fatty acid dioxygenase, involved in the biosynthesis of the linoleic acid derived oxylipin psiBalpha. PpoA is required for balancing anamorph and teleomorph development. Deletion of ppoA significantly reduced the level of psiBalpha and increased the ratio of aSexual to Sexual Spore numbers 4-fold. In contrast, forced expression of ppoA resulted in elevated levels of psiBalpha and decreased the ratio of aSexual to Sexual Spore numbers 6-fold. ppoA expression is mediated by two developmental regulators, VeA and the COP9 signalosome, such that ppoA transcript levels are correlated with the initiation of aSexual and Sexual fruiting body formation. PpoA localizes in lipid bodies in these tissues. These data support an important role for oxylipins in integrating mitotic and meiotic Spore development.
Zheng Wang - One of the best experts on this subject based on the ideXlab platform.
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Gene Expression Differences among Three Neurospora Species Reveal Genes Required for Sexual Reproduction in Neurospora crassa
2016Co-Authors: Nina A. Lehr, Zheng Wang, Frances Trail, David A. Hewitt, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression acros
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Gene expression differences among three Neurospora species reveal genes required for Sexual reproduction in Neurospora crassa.
PLOS ONE, 2014Co-Authors: Nina A. Lehr, David Hewitt, Francesc López-giráldez, Zheng Wang, Ning Li, Frances Trail, Jeffrey P TownsendAbstract:Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for Sexual Spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of Sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during Sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression across developmental stages increased more in N. crassa relative to the other species. Then, in N. crassa, we characterized the phenotypes of fruiting bodies arising from crosses of homozygous knockout strains of the top genes. Eight N. crassa genes were found to be critical for the successful formation of perithecia. The absence of these genes in these crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora Sexual reproduction, which is also of great importance with regard to other multicellular ascomycetes, including perithecium-forming pathogens, such as Claviceps purpurea, Ophiostoma ulmi, and Glomerella graminicola.