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Kurt-Kızıldoğan A, Otur Ç, Yıldırım K, Kavas M, Abanoz-Seçgin B. In-depth comparative transcriptome analysis of Purpureocillium sp. CB1 under cadmium stress. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12655-5. [PMID: 37436480 DOI: 10.1007/s00253-023-12655-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 06/13/2023] [Accepted: 06/19/2023] [Indexed: 07/13/2023]
Abstract
Fungal bioremediation is a very attractive tool to cope with environmental pollution. We aimed to decipher the cadmium (Cd) response of Purpureocillium sp. CB1, isolated from polluted soil, at transcriptome level by RNA-sequencing (RNA-seq). We used 500 and 2500 mg/L of Cd2+ concentrations at two time points (t6;36). RNA-seq determined 620 genes that were co-expressed in all samples. The highest number of differentially expressed genes (DEGs) was obtained within the first six h of exposure to 2500 mg/L of Cd2+. Several genes encoding transcriptional regulators, transporters, heat shock proteins, and oxidative stress-related genes were differentially expressed under Cd2+ stress. Remarkably, the genes that encode salicylate hydroxylase, which is involved in naphthalene biodegradation pathway, were significantly overexpressed. Utilization of diesel as the sole carbon source by CB1 even in the presence of Cd2+ supported concomitant upregulation of hydrocarbon degradation pathway genes. Furthermore, leucinostatin-related gene expression levels increased under Cd2+ stress. In addition, leucinostatin extracts from Cd2+-treated CB1 cultures showed higher antifungal activity than the control. Notably, Cd2+ in CB1 was mainly found as bound to the cell wall, thus confirming its adsorption potential. Cd2+ stress slightly reduced growth and led to mycelial malformation due to Cd2+ adsorption, especially at a concentration of 2500 mg/L at t36. A strong correlation was recorded between RNA-seq and reverse-transcriptase-quantitative polymerase chain reaction (RT-qPCR) data. In conclusion, the study represents the first transcriptome analysis of Purpureocillium sp. under Cd2+ stress, providing insights into the primary targets for rational engineering to construct strains with remarkable bioremediation potency. KEY POINTS: • Upregulation of genes encoding salicylate hydroxylases under Cd2+ stress • Maximum Cd2+ adsorption at 500 mg/L at t36 as tightly bound to the cell wall • Concordant bioremediation potential of CB1 on Cd2+ and diesel.
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Affiliation(s)
- Aslıhan Kurt-Kızıldoğan
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139, Samsun, Turkey.
| | - Çiğdem Otur
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139, Samsun, Turkey
| | - Kubilay Yıldırım
- Department of Molecular Biology and Genetics, Ondokuz Mayıs University, 55139, Samsun, Turkey
| | - Musa Kavas
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139, Samsun, Turkey
| | - Büşra Abanoz-Seçgin
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139, Samsun, Turkey
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Schalamun M, Molin EM, Schmoll M. RGS4 impacts carbohydrate and siderophore metabolism in Trichoderma reesei. BMC Genomics 2023; 24:372. [PMID: 37400774 PMCID: PMC10316542 DOI: 10.1186/s12864-023-09467-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/20/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Adaptation to complex, rapidly changing environments is crucial for evolutionary success of fungi. The heterotrimeric G-protein pathway belongs to the most important signaling cascades applied for this task. In Trichoderma reesei, enzyme production, growth and secondary metabolism are among the physiological traits influenced by the G-protein pathway in a light dependent manner. RESULTS Here, we investigated the function of the SNX/H-type regulator of G-protein signaling (RGS) protein RGS4 of T. reesei. We show that RGS4 is involved in regulation of cellulase production, growth, asexual development and oxidative stress response in darkness as well as in osmotic stress response in the presence of sodium chloride, particularly in light. Transcriptome analysis revealed regulation of several ribosomal genes, six genes mutated in RutC30 as well as several genes encoding transcription factors and transporters. Importantly, RGS4 positively regulates the siderophore cluster responsible for fusarinine C biosynthesis in light. The respective deletion mutant shows altered growth on nutrient sources related to siderophore production such as ornithine or proline in a BIOLOG phenotype microarray assay. Additionally, growth on storage carbohydrates as well as several intermediates of the D-galactose and D-arabinose catabolic pathway is decreased, predominantly in light. CONCLUSIONS We conclude that RGS4 mainly operates in light and targets plant cell wall degradation, siderophore production and storage compound metabolism in T. reesei.
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Affiliation(s)
- Miriam Schalamun
- AIT Austrian Institute of Technology GmbH, Bioresources Unit, Center for Health & Bioresources, Konrad Lorenz Strasse 24, Tulln, 3430 Austria
| | - Eva Maria Molin
- AIT Austrian Institute of Technology GmbH, Bioresources Unit, Center for Health & Bioresources, Konrad Lorenz Strasse 24, Tulln, 3430 Austria
| | - Monika Schmoll
- AIT Austrian Institute of Technology GmbH, Bioresources Unit, Center for Health & Bioresources, Konrad Lorenz Strasse 24, Tulln, 3430 Austria
- Division of Terrestrial Ecosystem Research, Centre of Microbiology and Ecosystem Science, University of Vienna, Djerassiplatz 1, Vienna, 1030 Austria
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3
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Cabrera IE, Oza Y, Carrillo AJ, Collier LA, Wright SJ, Li L, Borkovich KA. Regulator of G Protein Signaling Proteins Control Growth, Development and Cellulase Production in Neurospora crassa. J Fungi (Basel) 2022; 8:jof8101076. [PMID: 36294641 PMCID: PMC9604755 DOI: 10.3390/jof8101076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/05/2022] [Accepted: 10/11/2022] [Indexed: 11/30/2022] Open
Abstract
Heterotrimeric (αβγ) G protein signaling pathways are critical environmental sensing systems found in eukaryotic cells. Exchange of GDP for GTP on the Gα subunit leads to its activation. In contrast, GTP hydrolysis on the Gα is accelerated by Regulator of G protein Signaling (RGS) proteins, resulting in a return to the GDP-bound, inactive state. Here, we analyzed growth, development and extracellular cellulase production in strains with knockout mutations in the seven identified RGS genes (rgs-1 to rgs-7) in the filamentous fungus, Neurospora crassa. We compared phenotypes to those of strains with either knockout mutations or expressing predicted constitutively activated, GTPase-deficient alleles for each of the three Gα subunit genes (gna-1Q204L, gna-2Q205L or gna-3Q208L). Our data revealed that six RGS mutants have taller aerial hyphae than wild type and all seven mutants exhibit reduced asexual sporulation, phenotypes shared with strains expressing the gna-1Q204L or gna-3Q208L allele. In contrast, Δrgs-1 and Δrgs-3 were the only RGS mutants with a slower growth rate phenotype, a defect in common with gna-1Q204L strains. With respect to female sexual development, Δrgs-1 possessed defects most similar to gna-3Q208L strains, while those of Δrgs-2 mutants resembled strains expressing the gna-1Q204L allele. Finally, we observed that four of the seven RGS mutants had significantly different extracellular cellulase levels relative to wild type. Of interest, the Δrgs-2 mutant had no detectable activity, similar to the gna-3Q208L strain. In contrast, the Δrgs-1 and Δrgs-4 mutants and gna-1Q204L and gna-2Q205L strains exhibited significantly higher cellulase activity than wild type. With the exception of sexual development, our results demonstrate the greatest number of genetic interactions between rgs-1 and gna-1 and rgs-2 and gna-3 in N. crassa.
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Gan T, An H, Tang M, Chen H. Phylogeny of Regulators of G-Protein Signaling Genes in Leptographium qinlingensis and Expression Levels of Three RGSs in Response to Different Terpenoids. Microorganisms 2022; 10:microorganisms10091698. [PMID: 36144299 PMCID: PMC9506272 DOI: 10.3390/microorganisms10091698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Leptographium qinlingensis is a bark beetle-vectored pine pathogen in the Chinese white pine beetle (Dendroctonus armandi) epidemic in Northwest China. L. qinlingensis colonizes pines despite the trees’ massive oleoresin terpenoid defenses. Regulators of G-protein signaling (RGS) proteins modulate heterotrimeric G-protein signaling negatively and play multiple roles in the growth, asexual development, and pathogenicity of fungi. In this study, we have identified three L. qinlingensis RGS genes, and the phylogenetic analysis shows the highest homology with the regulators of G-protein signaling proteins sequence from Ophiostoma piceae and Grosmannia clavigera. The expression profiles of three RGSs in the mycelium of L. qinlingensis treated with six different terpenoids were detected, as well as their growth rates. Under six terpenoid treatments, the growth and reproduction in L. qinlingensis were significantly inhibited, and the growth inflection day was delayed from 8 days to 12–13 days. By analyzing the expression level of three RGS genes of L. qinlingensis with different treatments, results indicate that LqFlbA plays a crucial role in controlling fungal growth, and both LqRax1 and LqRgsA are involved in overcoming the host chemical resistances and successful colonization.
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Affiliation(s)
| | | | | | - Hui Chen
- Correspondence: ; Tel.: +86-135-1911-6730
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Liu X, Miao Q, Zhou Z, Lu S, Li J. Identification of Three Novel Conidiogenesis-Related Genes in the Nematode-Trapping Fungus Arthrobotrys oligospora. Pathogens 2022; 11:pathogens11070717. [PMID: 35889964 PMCID: PMC9324328 DOI: 10.3390/pathogens11070717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/15/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
For filamentous fungi, conidiogenesis is the most common reproductive strategy for environmental dispersal, invasion, and proliferation. Understanding the molecular mechanisms controlling conidiation and increasing conidium yield may provide promising applications in commercial development in the future for nematode-trapping fungi. However, the molecular mechanism for regulating conidium production of filamentous fungi is not fully understood. In this study, we characterized three novel conidiogenesis-related genes via gene knockout in A. oligospora. The absence of the genes AoCorA and AoRgsD caused significant increases in conidia production, while the absence of AoXlnR resulted in a decrease in conidiogenesis. Moreover, we characterized the ortholog of AbaA, a well-known conidiogenesis-related gene in Aspergillus nidulans. The deletion of AoAbaA not only completely abolished conidium production but also affected the production of nematode-trapping traps.
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Regulator of G Protein Signaling Contributes to the Development and Aflatoxin Biosynthesis in Aspergillus flavus through the Regulation of Gα Activity. Appl Environ Microbiol 2022; 88:e0024422. [PMID: 35638847 PMCID: PMC9238415 DOI: 10.1128/aem.00244-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterotrimeric G-proteins play crucial roles in growth, asexual development, and pathogenicity of fungi. The regulator of G-protein signaling (RGS) proteins function as negative regulators of the G proteins to control the activities of GTPase in Gα subunits. In this study, we functionally characterized the six RGS proteins (i.e., RgsA, RgsB, RgsC, RgsD, RgsE, and FlbA) in the pathogenic fungus Aspergillus flavus. All the aforementioned RGS proteins were also found to be functionally different in conidiation, aflatoxin (AF) biosynthesis, and pathogenicity in A. flavus. Apart from FlbA, all other RGS proteins play a negative role in regulating both the synthesis of cyclic AMP (cAMP) and the activation of protein kinase A (PKA). Additionally, we also found that although RgsA and RgsE play a negative role in regulating the FadA-cAMP/PKA pathway, they function distinctly in aflatoxin biosynthesis. Similarly, RgsC is important for aflatoxin biosynthesis by negatively regulating the GanA-cAMP/PKA pathway. PkaA, which is the cAMP-dependent protein kinase catalytic subunit, also showed crucial influences on A. flavus phenotypes. Overall, our results demonstrated that RGS proteins play multiple roles in the development, pathogenicity, and AF biosynthesis in A. flavus through the regulation of Gα subunits and cAMP-PKA signals. IMPORTANCE RGS proteins, as crucial regulators of the G protein signaling pathway, are widely distributed in fungi, while little is known about their roles in Aspergillus flavus development and aflatoxin. In this study, we identified six RGS proteins in A. flavus and revealed that these proteins have important functions in the regulation of conidia, sclerotia, and aflatoxin formation. Our findings provide evidence that the RGS proteins function upstream of cAMP-PKA signaling by interacting with the Gα subunits (GanA and FadA). This study provides valuable information for controlling the contamination of A. flavus and mycotoxins produced by this fungus in pre- and postharvest of agricultural crops.
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Yang K, Tian J, Keller NP. Post-translational modifications drive secondary metabolite biosynthesis in Aspergillus: a review. Environ Microbiol 2022; 24:2857-2881. [PMID: 35645150 PMCID: PMC9545273 DOI: 10.1111/1462-2920.16034] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 12/26/2022]
Abstract
Post‐translational modifications (PTMs) are important for protein function and regulate multiple cellular processes and secondary metabolites (SMs) in fungi. Aspergillus species belong to a genus renown for an abundance of bioactive secondary metabolites, many important as toxins, pharmaceuticals and in industrial production. The genes required for secondary metabolites are typically co‐localized in biosynthetic gene clusters (BGCs), which often localize in heterochromatic regions of genome and are ‘turned off’ under laboratory condition. Efforts have been made to ‘turn on’ these BGCs by genetic manipulation of histone modifications, which could convert the heterochromatic structure to euchromatin. Additionally, non‐histone PTMs also play critical roles in the regulation of secondary metabolism. In this review, we collate the known roles of epigenetic and PTMs on Aspergillus SM production. We also summarize the proteomics approaches and bioinformatics tools for PTM identification and prediction and provide future perspectives on the emerging roles of PTM on regulation of SM biosynthesis in Aspergillus and other fungi.
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Affiliation(s)
- Kunlong Yang
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China.,Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
| | - Jun Tian
- School of Life Science, Jiangsu Normal University, Xuzhou, 221116, Jiangsu Province, People's Republic of China
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53705, USA
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Durieux MF, Melloul É, Jemel S, Roisin L, Dardé ML, Guillot J, Dannaoui É, Botterel F. Galleria mellonella as a screening tool to study virulence factors of Aspergillus fumigatus. Virulence 2021; 12:818-834. [PMID: 33682618 PMCID: PMC7946008 DOI: 10.1080/21505594.2021.1893945] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
The invertebrate Galleria mellonella has increasingly and widely been used in the last few years to study complex host–microbe interactions. Aspergillus fumigatus is one of the most pathogenic fungi causing life-threatening diseases in humans and animals. Galleria mellonella larvae has been proven as a reliable model for the analysis of pathogenesis and virulence factors, enable to screen a large number of A. fumigatus strains. This review describes the different uses of G. mellonella to study A. fumigatus and provides a comparison of the different protocols to trace fungal pathogenicity. The review also includes a summary of the diverse mutants tested in G. mellonella, and their respective contribution to A. fumigatus virulence. Previous investigations indicated that G. mellonella should be considered as an interesting tool even though a mammalian model may be required to complete and verify initial data.
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Affiliation(s)
- Marie-Fleur Durieux
- Laboratoire de Parasitologie - Mycologie, CHU de Limoges, Limoges, France.,EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France
| | - Élise Melloul
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France
| | - Sana Jemel
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France
| | - Lolita Roisin
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France
| | - Marie-Laure Dardé
- Laboratoire de Parasitologie - Mycologie, CHU de Limoges, Limoges, France
| | - Jacques Guillot
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France.,École Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Éric Dannaoui
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France.,Unité de Parasitologie-mycologie, Service de Microbiologie, Université Paris Descartes, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Françoise Botterel
- EA 7380 Dynamic, Université Paris Est Créteil, EnvA, USC ANSES, Créteil, France.,Unité de Mycologie, Département de Prévention, Diagnostic Et Traitement Des Infections, Groupe Hospitalier Henri Mondor - Albert Chenevier, APHP, France
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9
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Heterotrimeric G-protein signalers and RGSs in Aspergillus fumigatus. Pathogens 2020; 9:pathogens9110902. [PMID: 33126739 PMCID: PMC7693823 DOI: 10.3390/pathogens9110902] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/18/2022] Open
Abstract
The heterotrimeric G-protein (G-protein) signaling pathway is one of the most important signaling pathways that transmit external signals into the inside of the cell, triggering appropriate biological responses. The external signals are sensed by various G-protein-coupled receptors (GPCRs) and transmitted into G-proteins consisting of the α, β, and γ subunits. Regulators of G-protein signaling (RGSs) are the key controllers of G-protein signaling pathways. GPCRs, G-proteins, and RGSs are the primary upstream components of the G-protein signaling pathway, and they are highly conserved in most filamentous fungi, playing diverse roles in biological processes. Recent studies characterized the G-protein signaling components in the opportunistic pathogenic fungus Aspergillus fumigatus. In this review, we have summarized the characteristics and functions of GPCRs, G-proteins, and RGSs, and their regulatory roles in governing fungal growth, asexual development, germination, stress tolerance, and virulence in A. fumigatus.
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10
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Abstract
G-protein-coupled receptors (GPCRs) are the largest family of transmembrane receptors in fungi. These receptors have an important role in the transduction of extracellular signals into intracellular sites in response to diverse stimuli. They enable fungi to coordinate cell function and metabolism, thereby promoting their survival and propagation, and sense certain fundamentally conserved elements, such as nutrients, pheromones, and stress, for adaptation to their niches, environmental stresses, and host environment, causing disease and pathogen virulence. This chapter highlights the role of GPCRs in fungi in coordinating cell function and metabolism. Fungal cells sense the molecular interactions between extracellular signals. Their respective sensory systems are described here in detail.
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Affiliation(s)
- Abd El-Latif Hesham
- Department of Genetics Faculty of Agriculture, Beni-Suef University, Beni-Suef, Egypt
| | | | | | | | - Vijai Kumar Gupta
- AgroBioSciences and Chemical & Biochemical Sciences Department, University Mohammed VI Polytechnic (UM6P), Benguerir, Morocco
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Choi YH, Lee MW, Igbalajobi OA, Yu JH, Shin KS. Transcriptomic and Functional Studies of the RGS Protein Rax1 in Aspergillus fumigatus. Pathogens 2019; 9:pathogens9010036. [PMID: 31906167 PMCID: PMC7168642 DOI: 10.3390/pathogens9010036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/26/2019] [Accepted: 12/30/2019] [Indexed: 12/24/2022] Open
Abstract
In the comparative transcriptomic studies of wild type (WT) and rax1 null mutant strains, we obtained an average of 22,222,727 reads of 101 bp per sample and found that 183 genes showed greater than 2.0-fold differential expression, where 92 and 91 genes were up-and down-regulated in Δrax1 compared to WT, respectively. In accordance with the significantly reduced levels of gliM and casB transcripts in the absence of rax1, the Δrax1 mutant exhibited increased sensitivity to exogenous gliotoxin (GT) without affecting levels of GT production. Moreover, Δrax1 resulted in significantly restricted colony growth and reduced viability under endoplasmic reticulum stress condition. In summary, Rax1 positively affects expression of gliM and metacaspase genes.
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Affiliation(s)
- Yong-Ho Choi
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea;
| | - Min-Woo Lee
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Chungcheongnam-do 31151, Korea;
| | - Olumuyiwa Ayokunle Igbalajobi
- Department of Microbiology, Institute for Applied Biosciences, Karlsruhe Institute of Technology, Fritz-Haber Weg 4, D-76131 Karlsruhe, Germany;
| | - Jae-Hyuk Yu
- Departments of Bacteriology and Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Systems Biotechnology, Konkuk University, Seoul 05029, Korea
- Correspondence: (J.-H.Y.); (K.-S.S.)
| | - Kwang-Soo Shin
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea;
- Correspondence: (J.-H.Y.); (K.-S.S.)
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Lwin HP, Choi YH, Lee MW, Yu JH, Shin KS. RgsA Attenuates the PKA Signaling, Stress Response, and Virulence in the Human Opportunistic Pathogen Aspergillus fumigatus. Int J Mol Sci 2019; 20:ijms20225628. [PMID: 31717953 PMCID: PMC6888639 DOI: 10.3390/ijms20225628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
The regulator of G-protein signaling (RGS) proteins play an important role in upstream control of heterotrimeric G-protein signaling pathways. In the genome of the human opportunistic pathogenic fungus Aspergillus fumigatus, six RGS protein-encoding genes are present. To characterize the rgsA gene predicted to encode a protein with an RGS domain, we generated an rgsA null mutant and observed the phenotypes of the mutant. The deletion (Δ) of rgsA resulted in increased radial growth and enhanced asexual sporulation in both solid and liquid culture conditions. Accordingly, transcripts levels of the key asexual developmental regulators abaA, brlA, and wetA are elevated in the ΔrgsA mutant. Moreover, ΔrgsA resulted in elevated spore germination rates in the absence of a carbon source. The activity of cAMP-dependent protein kinase A (PKA) and mRNA levels of genes encoding PKA signaling elements are elevated by ΔrgsA. In addition, mRNA levels of genes associated with stress-response signaling increased with the lack of rgsA, and the ΔrgsA spores showed enhanced tolerance against oxidative stressors. Comparative transcriptomic analyses revealed that the ΔrgsA mutant showed higher mRNA levels of gliotoxin (GT) biosynthetic genes. Accordingly, the rgsA null mutant exhibited increased production of GT and elevated virulence in the mouse. Conversely, the majority of genes encoding glucan degrading enzymes were down-regulated by ΔrgsA, and endoglucanase activities were reduced. In summary, RgsA plays multiple roles, governing growth, development, stress responses, virulence, and external polymer degradation-likely by attenuating PKA signaling.
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Affiliation(s)
- Hnin Phyu Lwin
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
| | - Yong-Ho Choi
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
| | - Min-Woo Lee
- Soonchunhyang Institute of Medi-bio Science, Soonchunhyang University, Chungcheongnam-do 31151, Korea;
| | - Jae-Hyuk Yu
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Systems Biotechnology, Konkuk University, Seoul 05029, Korea
- Correspondence: (J.-H.Y.); (K.-S.S.); Tel.: +1-608-262-4696 (J.-H.Y.); +82-42-280-2439 (K.-S.S.); Fax: +1-608-262-2976 (J.-H.Y.); +82-42-280-2608 (K.-S.S.)
| | - Kwang-Soo Shin
- Department of Microbiology, Graduate School, Daejeon University, Daejeon 34520, Korea; (H.P.L.); (Y.-H.C.)
- Correspondence: (J.-H.Y.); (K.-S.S.); Tel.: +1-608-262-4696 (J.-H.Y.); +82-42-280-2439 (K.-S.S.); Fax: +1-608-262-2976 (J.-H.Y.); +82-42-280-2608 (K.-S.S.)
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