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Jan Schirawski - One of the best experts on this subject based on the ideXlab platform.
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Positively Selected Effector Genes and Their Contribution to Virulence in the Smut Fungus Sporisorium reilianum
2018Co-Authors: Gabriel Schweizer, Regine Kahmann, Jan Schirawski, Gertrud Mannhaupt, Karin Münch, Julien DutheilAbstract:Plants and fungi display a broad range of interactions in natural and agricultural ecosystems ranging from symbiosis to parasitism. These ecological interactions result in coevolution between genes belonging to different partners. A well-understood example is secreted fungal effector proteins and their host targets, which play an important role in pathogenic interactions. Biotrophic smut fungi (Basidiomycota) are well-suited to investigate the evolution of plant pathogens, because several reference genomes and genetic tools are available for these species. Here, we used the genomes of Sporisorium reilianum f. sp. zeae and S. reilianum f. sp. reilianum, two closely related formae speciales infecting maize and sorghum, respectively, together with the genomes of Ustilago hordei, Ustilago maydis, and Sporisorium scitamineum to identify and characterize genes displaying signatures of positive selection. We identified 154 gene families having undergone positive selection during species divergence in at least one lineage, among which 77% were identified in the two investigated formae speciales of S. reilianum. Remarkably, only 29% of positively selected genes encode predicted secreted proteins. We assessed the contribution to virulence of nine of these candidate effector genes in S. reilianum f. sp. zeae by deleting individual genes, including a homologue of the effector gene pit2 previously characterized in U. maydis. Only the pit2 deletion mutant was found to be strongly reduced in virulence. Additional experiments are required to understand the molecular mechanisms underlying the selection forces acting on the other candidate effector genes, as well as the large fraction of positively selected genes encoding predicted cytoplasmic proteins.
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suppressor of apical dominance1 of Sporisorium reilianum changes inflorescence branching at early stages in di and monocot plants and induces fruit abortion in arabidopsis thaliana
2016Co-Authors: Frank Drechsler, Patrick Schwinges, Jan SchirawskiAbstract:Sporisorium reilianum f. sp. zeae is a biotrophic smut fungus that infects maize (Zea mays). Among others, the fungus-plant interaction is governed by secreted fungal effector proteins. The effector SUPPRESSOR OF APICAL DOMINANCE1 (SAD1) changes the development of female inflorescences and induces outgrowth of subapical ears in S. reilianum-infected maize. When stably expressed in Arabidopsis thaliana as a GFP-SAD1 fusion protein, SAD1 induces earlier inflorescence branching and abortion of siliques. Absence of typical hormone-dependent phenotypes in other parts of the transgenic A. thaliana plants expressing GFP-SAD1 hint to a hormone-independent induction of bud outgrowth by SAD1. Silique abortion and bud outgrowth are also known to be controlled by carbon source concentration and by stress-induced molecules, making these factors interesting potential SAD1 targets.
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A Tale of Genome Compartmentalization: The Evolution of Virulence Clusters in Smut Fungi
2016Co-Authors: Julien Dutheil, Jan Schirawski, Gertrud Mannhaupt, Gabriel Schweizer, Christian M.k. Sieber, Martin Münsterkötter, Ulrich Güldener, Regine KahmannAbstract:Smut fungi are plant pathogens mostly parasitizing wild species of grasses as well as domesticated cereal crops. Genome analysis of several smut fungi including Ustilago maydis revealed a singular clustered organization of genes encoding secreted effectors. In U. maydis, many of these clusters have a role in virulence. Reconstructing the evolutionary history of clusters of effector genes is difficult because of their intrinsically fast evolution, which erodes the phylogenetic signal and homology relationships. Here, we describe the use of comparative evolutionary analyses of quality draft assemblies of genomes to study the mechanisms of this evolution. We report the genome sequence of a South African isolate of Sporisorium scitamineum, a smut fungus parasitizing sugar cane with a phylogenetic position intermediate to the two previously sequenced species U. maydis and Sporisorium reilianum. We show that the genome of S. scitamineum contains more and larger gene clusters encoding secreted effectors than any previously described species in this group. We trace back the origin of the clusters and find that their evolution is mainly driven by tandem gene duplication. In addition, transposable elements play a major role in the evolution of the clustered genes. Transposable elements are significantly associated with clusters of genes encoding fast evolving secreted effectors. This suggests that such clusters represent a case of genome compartmentalization that restrains the activity of transposable elements on genes under diversifying selection for which this activity is potentially beneficial, while protecting the rest of the genome from its deleterious effect.
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comparative genomics of plant fungal pathogens the ustilago Sporisorium paradigm
2014Co-Authors: Theresa Wollenberg, Jan SchirawskiAbstract:The closely related smut fungi Ustilago maydis, U. hordei, and Sporisorium reilianum f. sp. zeae are facultatively biotrophic basidiomycetes that occur ubiquitously. Teliospores germinate to produce sporidia of different mating type that grow saprophytically and multiply mitotically by budding [1]. For mass proliferation and sexual genetic exchange, successful colonization of economically important crop plants like maize, barley, and oats is a prerequisite. Mating of compatible haploid yeast cells leads to the formation of dikaryotic filaments that are infection competent. These filaments enter their hosts by penetration of the leaf surface [2]. Once inside the plant, filaments multiply in the affected tissue and induce spore formation in tumors near the penetration site (U. maydis) [3] or spread through the entire plant and form spores in inflorescences (S. reilianum and U. hordei) [4], [5]. Although presence of the fungus is clearly detected [6], defense reactions of native host plants are very limited, allowing fungal spread initially without major plant tissue damage. In fact, a living host plant is required to provide nutrients for massive fungal proliferation and successful spore formation.
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host specificity of Sporisorium reilianum is tightly linked to generation of the phytoalexin luteolinidin by sorghum bicolor
2012Co-Authors: Katja Zuther, Jorg Kahnt, Jan Utermark, Julia Imkampe, Simon Uhse, Jan SchirawskiAbstract:The smut fungus Sporisorium reilianum occurs in two varieties (S. reilianum f. sp. reilianum and S. reilianum f. sp. zeae) that cause head smut disease on sorghum and maize, respectively. Prior to plant infection, compatible haploid sporidia of S. reilianum fuse to form infectious dikaryotic hyphae that penetrate the leaf surface, spread throughout the plant, and reach the inflorescences, in which spore formation occurs. To elucidate the basis of host specificity of the two S. reilianum varieties, we compared disease etiology of S. reilianum f. sp. reilianum and S. reilianum f. sp. zeae on sorghum and maize. Both varieties could penetrate and multiply in both hosts. However, red spots appeared on inoculated leaves after sorghum infection with S. reilianum f. sp. zeae. Using matrix-assisted laser desorption-ionization time of flight analysis of leaf extracts, we show that sorghum reacts with the production of the red and orange phytoalexins luteolinidin and apigeninidin upon colonization by S. reilianum f....
Tanya Scharaschkin - One of the best experts on this subject based on the ideXlab platform.
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Taxonomic revision of Ustilago, Sporisorium and Macalpinomyces
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:Morphological characters within the Ustilago-Sporisorium-Macalpinomyces complex are defined explicitly. The genera Sporisorium and Anthracocystis are emended to reflect morphological synapomorphies. Three new genera, Langdonia, Stollia and Triodiomyces are described based on soral synapomorphies and host classification. The new classification of the Ustilago-Sporisorium-Macalpinomyces complex incorporates 142 new taxonomic combinations.
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Soral synapomorphies are significant for the systematics of the Ustilago-Sporisorium-Macalpinomyces complex (Ustilaginaceae)
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Ben Callaghan, Tanya ScharaschkinAbstract:The genera Ustilago, Sporisorium and Macalpinomyces are a polyphyletic complex of plant pathogenic fungi. The four main morphological characters used to define these genera have been considered homoplasious and not useful for resolving the complex. This study re-evaluates character homology and discusses the use of these characters for defining monophyletic groups recovered from a reconstructed phylogeny using four nuclear loci. Generic delimitation of smut fungi based on their hosts is also discussed as a means for identifying genera within this group. Morphological characters and host specificity can be used to circumscribe genera within the Ustilago-Sporisorium-Macalpinomyces complex.
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A review of the Ustilago-Sporisorium-Macalpinomyces complex.
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:The fungal genera Ustilago, Sporisorium and Macalpinomyces represent an unresolved complex. Taxa within the complex often possess characters that occur in more than one genus, creating uncertainty for species placement. Previous studies have indicated that the genera cannot be separated based on morphology alone. Here we chronologically review the history of the Ustilago-Sporisorium-Macalpinomyces complex, argue for its resolution and suggest methods to accomplish a stable taxonomy. A combined molecular and morphological approach is required to identify synapomorphic characters that underpin a new classification. Ustilago, Sporisorium and Macalpinomyces require explicit re-description and new genera, based on monophyletic groups, are needed to accommodate taxa that no longer fit the emended descriptions. A resolved classification will end the taxonomic confusion that surrounds generic placement of these smut fungi.
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A review of the Ustilago-Sporisorium-Macalpinomyces complex
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:The fungal genera Ustilago, Sporisorium and Macalpinomyces represent an unresolved complex. Taxa within the complex often possess characters that occur in more than one genus, creating uncertainty for species placement. Previous studies have indicated that the genera cannot be separated by morphology alone. Here we chronologically review the history of the Ustilago-Sporisorium-Macalpinomyces complex, argue for its resolution and suggest methods to accomplish a stable taxonomy. A combined molecular and morphological approach is required to identify synapomorphic characters that underpin a new classification. Ustilago, Sporisorium and Macalpinomyces require explicit re-description and new genera, based on monophyletic groups, are needed to accommodate taxa that no longer fit the emended descriptions. A resolved classification will end the taxonomic confusion that surrounds generic placement of these smut fungi.
Yi Zhen Deng - One of the best experts on this subject based on the ideXlab platform.
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histidine kinase sln1 and camp pka signaling pathways antagonistically regulate Sporisorium scitamineum mating and virulence via transcription factor prf1
2021Co-Authors: Enping Cai, Yi Zhen Deng, Changqing Chang, Shuquan Sun, Peishen Huang, Xian Sun, Yuting Wang, Zide JiangAbstract:Many prokaryotes and eukaryotes utilize two-component signaling pathways to counter environmental stress and regulate virulence genes associated with infection. In this study, we identified and characterized a conserved histidine kinase (SsSln1), which is the sensor of the two-component system of Sln1–Ypd1–Ssk1 in Sporisorium scitamineum. SsSln1 null mutant exhibited enhanced mating and virulence capabilities in S. scitamineum, which is opposite to what has been reported in Candida albicans. Further investigations revealed that the deletion of SsSLN1 enhanced SsHog1 phosphorylation and nuclear localization and thus promoted S. scitamineum mating. Interestingly, SsSln1 and cAMP/PKA signaling pathways antagonistically regulated the transcription of pheromone-responsive transcription factor SsPrf1, for regulating S. scitamineum mating and virulence. In short, the study depicts a novel mechanism in which the cross-talk between SsSln1 and cAMP/PKA pathways antagonistically regulates mating and virulence by balancing the transcription of the SsPRF1 gene in S. scitamineum.
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identification and functional analysis of the pheromone response factor gene of Sporisorium scitamineum
2019Co-Authors: Guining Zhu, Yi Zhen Deng, Guobing Cui, Bin Zhang, Changqing Chang, Meixin Yan, Enping Cai, Zhiqiang Wang, Chengwu Zou, Baoshan ChenAbstract:The sugarcane smut fungus Sporisorium scitamineum is bipolar and produces sporidia of two different mating types. During infection, haploid cells of opposite mating types can fuse to form dikaryotic hyphae that can colonize plant tissue. Mating and filamentation are therefore essential for S. scitamineum pathogenesis. In this study, we obtained one T-DNA insertion mutant disrupted in the gene encoding the pheromone response factor (Prf1), hereinafter named SsPRF1, of S. scitamineum, via Agrobacterium tumefaciens-mediated transformation (ATMT) mutagenesis. Targeted deletion of SsPRF1 resulted in mutants with phenotypes similar to the T-DNA insertion mutant, including failure to mate with a compatible wild-type partner strain and being non-pathogenic on its host sugarcane. qRT-PCR analyses showed that SsPRF1 was essential for the transcription of pheromone-responsive mating type genes of the a1 locus. These results show that SsPRF1 is involved in mating and pathogenicity and plays a key role in pheromone signaling and filamentous growth in S. scitamineum.
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the agc kinase ssagc1 regulates Sporisorium scitamineum mating filamentation and pathogenicity
2019Co-Authors: Yixu Wang, Yi Zhen Deng, Guobing Cui, Chengwei Huang, Bin Zhang, Changqing Chang, Zide Jiang, Lianhui ZhangAbstract:ABSTRACT Sporisorium scitamineum is the fungal pathogen causing severe sugarcane smut disease that leads to massive economic losses globally. S. scitamineum invades host cane by dikaryotic hyphae, formed after sexual mating of two haploid sporidia of opposite mating type. Therefore, mating/filamentation is critical for S. scitamineum pathogenicity, while its molecular mechanisms remain largely unknown. The AGC (cyclic AMP [cAMP]-dependent protein kinase 1 [protein kinase A {PKA}], cGMP-dependent protein kinase [PKG], and protein kinase C [PKC]) kinase family is a group of serine/threonine (Ser/Thr) protein kinases conserved among eukaryotic genomes, serving a variety of physiological functions, including cell growth, metabolism, differentiation, and cell death. In this study, we identified an AGC kinase, named SsAgc1 (for S. scitamineum Agc1), and characterized its function by reverse genetics. Our results showed that SsAgc1 is critical for S. scitamineum mating/filamentation and pathogenicity, and oxidative stress tolerance under some circumstances. Transcriptional profiling revealed that the SsAgc1 signaling pathway may control expression of the genes governing fungal mating/filamentation and tryptophan metabolism, especially for tryptophol production. We showed that tryptophan and tryptophol could at least partially restore ssagc1Δ mating/filamentation. Overall, our work revealed a signaling pathway mediated by AGC protein kinases to regulate fungal mating/filamentation, possibly through sensing and responding to tryptophol as signal molecules. IMPORTANCE The AGC signaling pathway represents a conserved distinct signaling pathway in regulation of fungal differentiation and virulence, while it has not been identified or characterized in the sugarcane smut fungus Sporisorium scitamineum. In this study, we identified a PAS domain-containing AGC kinase, SsAgc1, in S. scitamineum. Functional analysis revealed that SsAgc1 plays a regulatory role on the fungal dimorphic switch.
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the autophagy gene atg8 affects morphogenesis and oxidative stress tolerance in Sporisorium scitamineum
2019Co-Authors: Bin Zhang, Yixu Wang, Yi Zhen Deng, Guobing Cui, Changqing Chang, Haoyang Zhang, Baoshan Chen, Zide JiangAbstract:Abstract The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China, India and Brazil, etc. Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling, and was shown to be important for fungal cell growth, development, and pathogenicity. However, physiological function of autophagy has not been studied in S. scitamineum. In this study, we identified a conserved Atg8 protein, named as SsAtg8 and characterized its function. Our results showed that autophagy was blocked in the ssatg8Δ mutant, in nitrogen starvation. The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress. However, mating or filamenation was unaffected in the ssatg8Δ mutant in vitro. Overall we demonstrate that autophagy is dispensable for S. scitamineum mating/filamentation, while critical for oxidative stress tolerance and proper morphology in sporidial stage.
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camp pka signalling pathway regulates redox homeostasis essential for Sporisorium scitamineum mating filamentation and virulence
2019Co-Authors: Changqing Chang, Yi Zhen Deng, Lianhui Zhang, Enping Cai, Baoshan Chen, Dan Mei, Shanxu Qiu, Zide JiangAbstract:The fungal pathogen Sporisorium scitamineum causes sugarcane smut disease. The formation and growth of dikaryotic hypha after sexual mating is critical for S. scitamineum pathogenicity, however regulation of S. scitimineum mating has not been studied in detail. We identified and characterized the core components of the conserved cAMP/PKA pathway in S. scitamineum by reverse genetics. Our results showed that cAMP/PKA signalling pathway is essential for proper mating and filamentation, and thus critical for S. scitamineum virulence. We further demonstrated that an elevated intracellular ROS (reactive oxygen species) level promotes S. scitamineum mating-filamentation, via transcriptional regulation of ROS catabolic enzymes, and is under regulation of the cAMP/PKA signalling pathway. Furthermore, we found that fungal cAMP/PKA signalling pathway is also involved in regulation of host ROS response. Overall, our work displayed a positive role of elevated intracellular ROS in fungal differentiation and virulence.
Alistair R. Mctaggart - One of the best experts on this subject based on the ideXlab platform.
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Taxonomic revision of Ustilago, Sporisorium and Macalpinomyces
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:Morphological characters within the Ustilago-Sporisorium-Macalpinomyces complex are defined explicitly. The genera Sporisorium and Anthracocystis are emended to reflect morphological synapomorphies. Three new genera, Langdonia, Stollia and Triodiomyces are described based on soral synapomorphies and host classification. The new classification of the Ustilago-Sporisorium-Macalpinomyces complex incorporates 142 new taxonomic combinations.
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Soral synapomorphies are significant for the systematics of the Ustilago-Sporisorium-Macalpinomyces complex (Ustilaginaceae)
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Ben Callaghan, Tanya ScharaschkinAbstract:The genera Ustilago, Sporisorium and Macalpinomyces are a polyphyletic complex of plant pathogenic fungi. The four main morphological characters used to define these genera have been considered homoplasious and not useful for resolving the complex. This study re-evaluates character homology and discusses the use of these characters for defining monophyletic groups recovered from a reconstructed phylogeny using four nuclear loci. Generic delimitation of smut fungi based on their hosts is also discussed as a means for identifying genera within this group. Morphological characters and host specificity can be used to circumscribe genera within the Ustilago-Sporisorium-Macalpinomyces complex.
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A review of the Ustilago-Sporisorium-Macalpinomyces complex.
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:The fungal genera Ustilago, Sporisorium and Macalpinomyces represent an unresolved complex. Taxa within the complex often possess characters that occur in more than one genus, creating uncertainty for species placement. Previous studies have indicated that the genera cannot be separated based on morphology alone. Here we chronologically review the history of the Ustilago-Sporisorium-Macalpinomyces complex, argue for its resolution and suggest methods to accomplish a stable taxonomy. A combined molecular and morphological approach is required to identify synapomorphic characters that underpin a new classification. Ustilago, Sporisorium and Macalpinomyces require explicit re-description and new genera, based on monophyletic groups, are needed to accommodate taxa that no longer fit the emended descriptions. A resolved classification will end the taxonomic confusion that surrounds generic placement of these smut fungi.
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A review of the Ustilago-Sporisorium-Macalpinomyces complex
2012Co-Authors: Alistair R. Mctaggart, Roger G. Shivas, Kalman Vanky, Andrew D. W. Geering, Tanya ScharaschkinAbstract:The fungal genera Ustilago, Sporisorium and Macalpinomyces represent an unresolved complex. Taxa within the complex often possess characters that occur in more than one genus, creating uncertainty for species placement. Previous studies have indicated that the genera cannot be separated by morphology alone. Here we chronologically review the history of the Ustilago-Sporisorium-Macalpinomyces complex, argue for its resolution and suggest methods to accomplish a stable taxonomy. A combined molecular and morphological approach is required to identify synapomorphic characters that underpin a new classification. Ustilago, Sporisorium and Macalpinomyces require explicit re-description and new genera, based on monophyletic groups, are needed to accommodate taxa that no longer fit the emended descriptions. A resolved classification will end the taxonomic confusion that surrounds generic placement of these smut fungi.
Zide Jiang - One of the best experts on this subject based on the ideXlab platform.
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histidine kinase sln1 and camp pka signaling pathways antagonistically regulate Sporisorium scitamineum mating and virulence via transcription factor prf1
2021Co-Authors: Enping Cai, Yi Zhen Deng, Changqing Chang, Shuquan Sun, Peishen Huang, Xian Sun, Yuting Wang, Zide JiangAbstract:Many prokaryotes and eukaryotes utilize two-component signaling pathways to counter environmental stress and regulate virulence genes associated with infection. In this study, we identified and characterized a conserved histidine kinase (SsSln1), which is the sensor of the two-component system of Sln1–Ypd1–Ssk1 in Sporisorium scitamineum. SsSln1 null mutant exhibited enhanced mating and virulence capabilities in S. scitamineum, which is opposite to what has been reported in Candida albicans. Further investigations revealed that the deletion of SsSLN1 enhanced SsHog1 phosphorylation and nuclear localization and thus promoted S. scitamineum mating. Interestingly, SsSln1 and cAMP/PKA signaling pathways antagonistically regulated the transcription of pheromone-responsive transcription factor SsPrf1, for regulating S. scitamineum mating and virulence. In short, the study depicts a novel mechanism in which the cross-talk between SsSln1 and cAMP/PKA pathways antagonistically regulates mating and virulence by balancing the transcription of the SsPRF1 gene in S. scitamineum.
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the agc kinase ssagc1 regulates Sporisorium scitamineum mating filamentation and pathogenicity
2019Co-Authors: Yixu Wang, Yi Zhen Deng, Guobing Cui, Chengwei Huang, Bin Zhang, Changqing Chang, Zide Jiang, Lianhui ZhangAbstract:ABSTRACT Sporisorium scitamineum is the fungal pathogen causing severe sugarcane smut disease that leads to massive economic losses globally. S. scitamineum invades host cane by dikaryotic hyphae, formed after sexual mating of two haploid sporidia of opposite mating type. Therefore, mating/filamentation is critical for S. scitamineum pathogenicity, while its molecular mechanisms remain largely unknown. The AGC (cyclic AMP [cAMP]-dependent protein kinase 1 [protein kinase A {PKA}], cGMP-dependent protein kinase [PKG], and protein kinase C [PKC]) kinase family is a group of serine/threonine (Ser/Thr) protein kinases conserved among eukaryotic genomes, serving a variety of physiological functions, including cell growth, metabolism, differentiation, and cell death. In this study, we identified an AGC kinase, named SsAgc1 (for S. scitamineum Agc1), and characterized its function by reverse genetics. Our results showed that SsAgc1 is critical for S. scitamineum mating/filamentation and pathogenicity, and oxidative stress tolerance under some circumstances. Transcriptional profiling revealed that the SsAgc1 signaling pathway may control expression of the genes governing fungal mating/filamentation and tryptophan metabolism, especially for tryptophol production. We showed that tryptophan and tryptophol could at least partially restore ssagc1Δ mating/filamentation. Overall, our work revealed a signaling pathway mediated by AGC protein kinases to regulate fungal mating/filamentation, possibly through sensing and responding to tryptophol as signal molecules. IMPORTANCE The AGC signaling pathway represents a conserved distinct signaling pathway in regulation of fungal differentiation and virulence, while it has not been identified or characterized in the sugarcane smut fungus Sporisorium scitamineum. In this study, we identified a PAS domain-containing AGC kinase, SsAgc1, in S. scitamineum. Functional analysis revealed that SsAgc1 plays a regulatory role on the fungal dimorphic switch.
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the autophagy gene atg8 affects morphogenesis and oxidative stress tolerance in Sporisorium scitamineum
2019Co-Authors: Bin Zhang, Yixu Wang, Yi Zhen Deng, Guobing Cui, Changqing Chang, Haoyang Zhang, Baoshan Chen, Zide JiangAbstract:Abstract The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China, India and Brazil, etc. Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling, and was shown to be important for fungal cell growth, development, and pathogenicity. However, physiological function of autophagy has not been studied in S. scitamineum. In this study, we identified a conserved Atg8 protein, named as SsAtg8 and characterized its function. Our results showed that autophagy was blocked in the ssatg8Δ mutant, in nitrogen starvation. The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress. However, mating or filamenation was unaffected in the ssatg8Δ mutant in vitro. Overall we demonstrate that autophagy is dispensable for S. scitamineum mating/filamentation, while critical for oxidative stress tolerance and proper morphology in sporidial stage.
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camp pka signalling pathway regulates redox homeostasis essential for Sporisorium scitamineum mating filamentation and virulence
2019Co-Authors: Changqing Chang, Yi Zhen Deng, Lianhui Zhang, Enping Cai, Baoshan Chen, Dan Mei, Shanxu Qiu, Zide JiangAbstract:The fungal pathogen Sporisorium scitamineum causes sugarcane smut disease. The formation and growth of dikaryotic hypha after sexual mating is critical for S. scitamineum pathogenicity, however regulation of S. scitimineum mating has not been studied in detail. We identified and characterized the core components of the conserved cAMP/PKA pathway in S. scitamineum by reverse genetics. Our results showed that cAMP/PKA signalling pathway is essential for proper mating and filamentation, and thus critical for S. scitamineum virulence. We further demonstrated that an elevated intracellular ROS (reactive oxygen species) level promotes S. scitamineum mating-filamentation, via transcriptional regulation of ROS catabolic enzymes, and is under regulation of the cAMP/PKA signalling pathway. Furthermore, we found that fungal cAMP/PKA signalling pathway is also involved in regulation of host ROS response. Overall, our work displayed a positive role of elevated intracellular ROS in fungal differentiation and virulence.
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the map kinase sskpp2 is required for mating filamentation in Sporisorium scitamineum
2018Co-Authors: Yi Zhen Deng, Yixu Wang, Bin Zhang, Changqing Chang, Baoshan Chen, Shuquan Sun, Xiaomeng Zhang, Zide JiangAbstract:In the phytopathogenic fungus Sporisorium scitamineum, sexual mating between two compatible haploid cells and the subsequent formation of dikaryotic hyphae is essential for infection. This process was shown to be commonly regulated by a mitogen-activated protein kinase (MAPK) and a cAMP/PKA signaling pathway in the corn smut fungus Ustilago maydis but remains largely unknown in S. scitamineum. In this study, we identified a conserved putative MAP kinase Kpp2 in S. scitamineum and named it as SsKpp2. The sskpp2Δ mutant displayed significant reduction in mating/filamentation, which could be partially restored by addition of cAMP or tryptophol, a quorum-sensing molecule identified in budding yeast. Transcriptional profiling showed that genes governing S. scitamineum mating or tryptophol biosynthesis were significantly differentially regulated in the sskpp2Δ mutant compared to the WT, under mating condition. Our results demonstrate that the MAP kinase SsKpp2 is required for S. scitamineum mating/filamentation likely through regulating the conserved pheromone signal transduction pathway and tryptophol production.
