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Ijadpanahsaravi M, Teertstra WR, Wösten HAB. Inter- and intra-species heterogeneity in germination of Aspergillus conidia. Antonie Van Leeuwenhoek 2022; 115:1151-1164. [PMID: 35857156 PMCID: PMC9363317 DOI: 10.1007/s10482-022-01762-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/05/2022] [Indexed: 11/26/2022]
Abstract
Aspergilli are among the most abundant fungi worldwide. They degrade organic material and can be pathogens of plants and animals. Aspergilli spread by forming high numbers of conidia. Germination of these stress resistant asexual spores is characterized by a swelling and a germ tube stage. Here, we show that conidia of Aspergillusniger,Aspergillusoryzae,Aspergillusclavatus, Aspergillusnidulans and Aspergillusterreus show different swelling and germ tube formation dynamics in pure water or in water supplemented with (in)organic nutrients. Apart from inter-species heterogeneity, intra-species heterogeneity was observed within spore populations of the aspergilli except for A.terreus. Sub-populations of conidia differing in size and/or contrast showed different swelling and germ tube formation dynamics. Together, data imply that aspergilli differ in their competitive potential depending on the substrate. Moreover, results suggest that intra-species heterogeneity provides a bet hedging mechanism to optimize survival of aspergilli.
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Affiliation(s)
- Maryam Ijadpanahsaravi
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Wieke R. Teertstra
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Han A. B. Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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2
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Bleichrodt RJ, Wösten HAB. Visualising long distance sugar transport in fungi using infrared fluorescence scanning imaging. Fungal Genet Biol 2022; 161:103699. [PMID: 35489527 DOI: 10.1016/j.fgb.2022.103699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Mycelia of saprotrophic basidiomycetes can cover large areas in nature that are typified by their heterogeneous nutrient availability. This heterogeneity is overcome by long distance transport of nutrients within the hyphal network to sites where they are needed. It is therefore key to be able to study nutrient transport and its underlying mechanisms. An IRDye-conjugate was used for the first time for imaging transport in fungi. A method was set up for time-lapse, high spatial resolution infrared imaging of IRDye-labelled deoxyglucose (IRDye-DG) in Schizophyllum commune and Agaricus bisporus. Scanning imaging visualised the tracer in individual hyphae as well as deeper tissues in mushrooms (mm-cm depth). The advantage of using fluorescence scanning imaging of IRDye in contrast to radiolabelled tracers studies, is that a higher spatial resolution and higher sensitivity (244 fg/ml) can be obtained. Moreover, it has a large field of view (25 x 25 cm) compared to microscopy (µm-mm range), allowing relatively fast and detailed imaging of large dimension samples.
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Affiliation(s)
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
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3
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Ijadpanahsaravi M, Punt M, Wösten HAB, Teertstra WR. Minimal nutrient requirements for induction of germination of Aspergillus niger conidia. Fungal Biol 2020; 125:231-238. [PMID: 33622539 DOI: 10.1016/j.funbio.2020.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022]
Abstract
Aspergillus niger reproduces asexually by forming conidia. Here, the minimal nutrient requirements were studied that activate germination of A. niger conidia. To this end, germination was monitored in time using an oCelloScope imager. Data was used as input in an asymmetric model to describe the process of swelling and germ tube formation. The maximum number of spores (Pmax) that were activated to swell and to form germ tubes was 32.54% and 20.51%, respectively, in minimal medium with 50 mM glucose. In contrast, Pmax of swelling and germ tube formation was <1% in water or 50 mM glucose. Combining 50 mM glucose with either NaNO3, KH2PO4, or MgSO4 increased Pmax of swelling and germination up to 15.25% and 5.4%, respectively, while combining glucose with two of these inorganic components further increased these Pmax values up to 25.85% and 10.99%. Next, 10 mM amino acid was combined with a phosphate buffer and MgSO4. High (e.g. proline), intermediate and low (e.g. cysteine) inducing amino acids were distinguished. Together, a combination of an inducing carbon source with either inorganic phosphate, inorganic nitrogen or magnesium sulphate is the minimum requirement for A. niger conidia to germinate.
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Affiliation(s)
- Maryam Ijadpanahsaravi
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands.
| | - Maarten Punt
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands; TiFN, P.O. Box 557, 6700 AN, Wageningen, the Netherlands.
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands.
| | - Wieke R Teertstra
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands; TiFN, P.O. Box 557, 6700 AN, Wageningen, the Netherlands.
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4
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Herman KC, Wösten HAB, Fricker MD, Bleichrodt RJ. Growth induced translocation effectively directs an amino acid analogue to developing zones in Agaricus bisporus. Fungal Biol 2020; 124:1013-1023. [PMID: 33213781 DOI: 10.1016/j.funbio.2020.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/04/2020] [Accepted: 09/06/2020] [Indexed: 01/15/2023]
Abstract
The vegetative mycelium of Agaricus bisporus supplies developing white button mushrooms with water and nutrients. However, it is not yet known which part of the mycelium contributes to the feeding of the mushrooms and how this depends on growth conditions. Here we used photon counting scintillation imaging to track translocation of the 14C-radiolabeled metabolically inert amino acid analogue α-aminoisobutyric acid (14C-AIB). Translocation to the periphery of the mycelium was observed in actively growing vegetative mycelium with a velocity of up to 6.6 mm h-1, which was 30-fold higher than the growth rate. Furthermore, 14C-AIB translocated to neighboring colonies after fusion by anastomosis depending on the relative growth rate in these colonies. When mushrooms started to develop, translocation of 14C-AIB was redirected to the fruiting bodies via mycelium and hyphal cords. More abundant mycelial cord formation and a 5-fold higher rate of translocation was observed for cultures growing directionally from inoculum located at one side of the substrate, when compared to non-directional growth (inoculum mixed throughout the substrate). The maximum translocation distance was also greater (≥50 and 22 cm, respectively). In conclusion, 14C-AIB translocation switches between vegetative growth and towards developing mushrooms, especially via cords and when source-sink relationships change.
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Affiliation(s)
- Koen C Herman
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Mark D Fricker
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Robert-Jan Bleichrodt
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands.
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5
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Impact of maturation and growth temperature on cell-size distribution, heat-resistance, compatible solute composition and transcription profiles of Penicillium roqueforti conidia. Food Res Int 2020; 136:109287. [PMID: 32846509 DOI: 10.1016/j.foodres.2020.109287] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/30/2020] [Accepted: 04/30/2020] [Indexed: 02/03/2023]
Abstract
Penicillium roqueforti is a major cause of fungal food spoilage. Its conidia are the main dispersal structures of this fungus and therefore the main cause of food contamination. These stress resistant asexual spores can be killed by preservation methods such as heat treatment. Here, the effects of cultivation time and temperature on thermal resistance of P. roqueforti conidia were studied. To this end, cultures were grown for 3, 5, 7 and 10 days at 25 °C or for 7 days at 15, 25 and 30 °C. Conidia of 3- and 10-day-old cultures that had been grown at 25 °C had D56-values of 1.99 ± 0.15 min and 5.31 ± 1.04 min, respectively. The effect of cultivation temperature was most pronounced between P. roqueforti conidia cultured for 7 days at 15 °C and 30 °C, where D56-values of 1.12 ± 0.05 min and 4.19 ± 0.11 min were found, respectively. Notably, D56-values were not higher when increasing both cultivation time and temperature by growing for 10 days at 30 °C. A correlation was found between heat resistance of conidia and levels of trehalose and arabitol, while this was not found for glycerol, mannitol and erythritol. RNA-sequencing showed that the expression profiles of conidia of 3- to 10-day-old cultures that had been grown at 25 °C were distinct from conidia that had been formed at 15 °C and 30 °C for 7 days. Only 33 genes were upregulated at both prolonged incubation time and increased growth temperature. Their encoded proteins as well as trehalose and arabitol may form the core of heat resistance of P. roqueforti conidia.
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6
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van den Brule T, Punt M, Teertstra W, Houbraken J, Wösten H, Dijksterhuis J. The most heat-resistant conidia observed to date are formed by distinct strains of Paecilomyces variotii. Environ Microbiol 2019; 22:986-999. [PMID: 31444981 PMCID: PMC7065192 DOI: 10.1111/1462-2920.14791] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/22/2019] [Accepted: 08/22/2019] [Indexed: 12/20/2022]
Abstract
Fungi colonize habitats by means of spores. These cells are stress‐resistant compared with growing fungal cells. Fungal conidia, asexual spores, formed by cosmopolitan fungal genera like Penicillium, Aspergillus and Peacilomyces are dispersed by air. They are present in places where food products are stored and as a result, they cause food spoilage. Here, we determined the heterogeneity of heat resistance of conidia between and within strains of Paecilomyces variotii, a spoiler of foods such as margarine, fruit juices, canned fruits and non‐carbonized sodas. Out of 108 strains, 31 isolates showed a conidial survival >10% after a 10‐min‐heat treatment at 59°C. Three strains with different conidial heat resistance were selected for further phenotyping. Conidia of DTO 212‐C5 and DTO 032‐I3 showed 0.3% and 2.6% survival in the screening respectively, while survival of DTO 217‐A2 conidia was >10%. The decimal reduction times of these strains at 60°C (D60 value) were 3.7 ± 0.08, 5.5 ± 0.35 and 22.9 ± 2.00 min respectively. Further in‐depth analysis revealed that the three strains showed differences in morphology, spore size distributions, compatible solute compositions and growth under salt stress. Conidia of DTO 217‐A2 are the most heat‐resistant reported so far. The ecological consequences of this heterogeneity of resistance, including food spoilage, are discussed.
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Affiliation(s)
- Tom van den Brule
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Department of Applied and Industrial Mycology, Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Maarten Punt
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Utrecht University, Molecular Microbiology, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Wieke Teertstra
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Utrecht University, Molecular Microbiology, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Jos Houbraken
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Department of Applied and Industrial Mycology, Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | - Han Wösten
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Utrecht University, Molecular Microbiology, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Jan Dijksterhuis
- TiFN, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.,Department of Applied and Industrial Mycology, Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
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7
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Novak M, Čepin U, Hodnik V, Narat M, Jamnik M, Kraševec N, Sepčić K, Anderluh G. Functional studies of aegerolysin and MACPF-like proteins in Aspergillus niger. Mol Microbiol 2019; 112:1253-1269. [PMID: 31376198 DOI: 10.1111/mmi.14360] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2019] [Indexed: 12/21/2022]
Abstract
Proteins of the aegerolysin family have a high abundance in Fungi. Due to their specific binding to membrane lipids, and their membrane-permeabilization potential in concert with protein partner(s) belonging to a membrane-attack-complex/perforin (MACPF) superfamily, they were proposed as useful tools in different biotechnological and biomedical applications. In this work, we performed functional studies on expression of the genes encoding aegerolysin and MACPF-like proteins in Aspergillus niger. Our results suggest the sporulation process being crucial for strong induction of the expression of all these genes. However, deletion of either of the aegerolysin genes did not influence the growth, development, sporulation efficiency and phenotype of the mutants, indicating that aegerolysins are not key factors in the sporulation process. In all our expression studies we noticed a strong correlation in the expression of one aegerolysin and MACPF-like gene. Aegerolysins were confirmed to be secreted from the fungus. We also showed the specific interaction of a recombinant A. niger aegerolysin with an invertebrate-specific membrane sphingolipid. Moreover, using this protein labelled with mCherry we successfully stained insect cells membranes containing this particular sphingolipid. Our combined results suggest, that aegerolysins in this species, and probably also in other aspergilli, could be involved in defence against predators.
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Affiliation(s)
- Maruša Novak
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Urška Čepin
- BioSistemika Ltd and National Institute of Biology, Ljubljana, Slovenia
| | - Vesna Hodnik
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Mojca Narat
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Maja Jamnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Nada Kraševec
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
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8
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Iradi-Serrano M, Tola-García L, Cortese MS, Ugalde U. The Early Asexual Development Regulator fluG Codes for a Putative Bifunctional Enzyme. Front Microbiol 2019; 10:778. [PMID: 31057506 PMCID: PMC6478659 DOI: 10.3389/fmicb.2019.00778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/27/2019] [Indexed: 11/13/2022] Open
Abstract
FluG is a long recognized early regulator of asexual development in Aspergillus nidulans. fluG null mutants show profuse aerial growth and no conidial production. Initial studies reported sequence homology of FluG with a prokaryotic type I glutamine synthetase, but catalytic activity has not been demonstrated. In this study, we conducted an in-depth analysis of the FluG sequence, which revealed a single polypeptide containing a putative N-terminal amidohydrolase region linked to a putative C-terminal γ-glutamyl ligase region. Each region corresponded, separately and completely, to respective single function bacterial enzymes. Separate expression of these regions confirmed that the C-terminal region was essential for asexual development. The N-terminal region alone did not support conidial development, but contributed to increased conidial production under high nutrient availability. Point mutations directed at respective key catalytic residues in each region demonstrated that they were essential for biological function. Moreover, the substitution of the N- and C-terminal regions with homologs from Lactobacillus paracasei and Pseudomonas aeruginosa, respectively, maintained functionality, albeit with altered characteristics. Taken together, the results lead us to conclude that FluG is a bifunctional enzyme that participates in an as yet unidentified metabolic or signaling pathway involving a γ-glutamylated intermediate that contributes to developmental fate.
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Affiliation(s)
| | | | | | - Unai Ugalde
- Microbial Biochemistry Laboratory, Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country, San Sebastian, Spain
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9
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Maturation of conidia on conidiophores of Aspergillus niger. Fungal Genet Biol 2017; 98:61-70. [DOI: 10.1016/j.fgb.2016.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 12/12/2016] [Accepted: 12/19/2016] [Indexed: 11/23/2022]
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10
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A Transcriptome Meta-Analysis Proposes Novel Biological Roles for the Antifungal Protein AnAFP in Aspergillus niger. PLoS One 2016; 11:e0165755. [PMID: 27835655 PMCID: PMC5106034 DOI: 10.1371/journal.pone.0165755] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 10/17/2016] [Indexed: 02/06/2023] Open
Abstract
Understanding the genetic, molecular and evolutionary basis of cysteine-stabilized antifungal proteins (AFPs) from fungi is important for understanding whether their function is mainly defensive or associated with fungal growth and development. In the current study, a transcriptome meta-analysis of the Aspergillus niger γ-core protein AnAFP was performed to explore co-expressed genes and pathways, based on independent expression profiling microarrays covering 155 distinct cultivation conditions. This analysis uncovered that anafp displays a highly coordinated temporal and spatial transcriptional profile which is concomitant with key nutritional and developmental processes. Its expression profile coincides with early starvation response and parallels with genes involved in nutrient mobilization and autophagy. Using fluorescence- and luciferase reporter strains we demonstrated that the anafp promoter is active in highly vacuolated compartments and foraging hyphal cells during carbon starvation with CreA and FlbA, but not BrlA, as most likely regulators of anafp. A co-expression network analysis supported by luciferase-based reporter assays uncovered that anafp expression is embedded in several cellular processes including allorecognition, osmotic and oxidative stress survival, development, secondary metabolism and autophagy, and predicted StuA and VelC as additional regulators. The transcriptomic resources available for A. niger provide unparalleled resources to investigate the function of proteins. Our work illustrates how transcriptomic meta-analyses can lead to hypotheses regarding protein function and predict a role for AnAFP during slow growth, allorecognition, asexual development and nutrient recycling of A. niger and propose that it interacts with the autophagic machinery to enable these processes.
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11
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Hewitt SK, Foster DS, Dyer PS, Avery SV. Phenotypic heterogeneity in fungi: Importance and methodology. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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12
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Walisko R, Moench-Tegeder J, Blotenberg J, Wucherpfennig T, Krull R. The Taming of the Shrew--Controlling the Morphology of Filamentous Eukaryotic and Prokaryotic Microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:1-27. [PMID: 25796624 DOI: 10.1007/10_2015_322] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One of the most sensitive process characteristics in the cultivation of filamentous biological systems is their complex morphology. In submerged cultures, the observed macroscopic morphology of filamentous microorganisms varies from freely dispersed mycelium to dense spherical pellets consisting of a more or less dense, branched and partially intertwined network of hyphae. Recently, the freely dispersed mycelium form has been in high demand for submerged cultivation because this morphology enhances the growth and production of several valuable products. A distinct filamentous morphology and productivity are influenced by the environment and can be controlled by inoculum concentration, spore viability, pH value, cultivation temperature, dissolved oxygen concentration, medium composition, mechanical stress or process mode as well as through the addition of inorganic salts or microparticles, which provides the opportunity to tailor a filamentous morphology. The suitable morphology for a given bioprocess varies depending on the desired product. Therefore, the advantages and disadvantages of each morphological type should be carefully evaluated for every biological system. Because of the high industrial relevance of filamentous microorganisms, research in previous years has aimed at the development of tools and techniques to characterise their growth and obtain quantitative estimates of their morphological properties. The focus of this review is on current advances in the characterisation and control of filamentous morphology with a separation of eukaryotic and prokaryotic systems. Furthermore, recent strategies to tailor the morphology through classical biochemical process parameters, morphology and genetic engineering to optimise the productivity of these filamentous systems are discussed.
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Affiliation(s)
- Robert Walisko
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Gaußstraße 17, 38106, Braunschweig, Germany,
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13
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Pieuchot L, Lai J, Loh R, Leong F, Chiam KH, Stajich J, Jedd G. Cellular Subcompartments through Cytoplasmic Streaming. Dev Cell 2015; 34:410-20. [DOI: 10.1016/j.devcel.2015.07.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/26/2015] [Accepted: 07/30/2015] [Indexed: 01/16/2023]
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14
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Shimizu T, Yaegashi H, Ito T, Kanematsu S. Systemic RNA interference is not triggered by locally-induced RNA interference in a plant pathogenic fungus, Rosellinia necatrix. Fungal Genet Biol 2015; 76:27-35. [PMID: 25677378 DOI: 10.1016/j.fgb.2015.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/23/2015] [Accepted: 02/03/2015] [Indexed: 01/28/2023]
Abstract
The white root rot fungus, Rosellinia necatrix, damages a wide range of fruit trees. R. necatrix is known to host a variety of mycoviruses, and several of these have potential as biological control agents. RNA interference (RNAi) is a fungal defense mechanism against viral infection, and it is therefore important to understand the RNAi amplification and transmission systems in R. necatrix for effective use of mycoviruses in disease control. In this study, we describe an intriguing RNAi signal transmission phenomenon in R. necatrix. In R. necatrix transformants with autonomously replicating vectors carrying a hairpin structure to induce RNAi, the gene silencing effect was distributed locally and unevenly, based on the vector distribution. This indicates that R. necatrix has no mechanism to propagate silencing signals systemically, unlike Caenorhabditis elegans and Arabidopsis thaliana. Furthermore, the expression of RNA-dependent RNA polymerase homologs was not upregulated during RNAi induction, suggesting that silencing signals are not amplified at sufficient levels to induce systemic RNAi in R. necatrix. Our results also suggest that, in addition to hairpin-induced RNAi, there is either a 5' transitive RNAi or quelling-like gene silencing system in R. necatrix. This is the first study demonstrating that systemic RNAi is not induced by local RNAi in fungi.
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Affiliation(s)
- Takeo Shimizu
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), 92-24 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan
| | - Hajime Yaegashi
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), 92-24 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan
| | - Tsutae Ito
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), 92-24 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan
| | - Satoko Kanematsu
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), 92-24 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan.
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15
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Sugai-Guérios MH, Balmant W, Furigo A, Krieger N, Mitchell DA. Modeling the Growth of Filamentous Fungi at the Particle Scale in Solid-State Fermentation Systems. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:171-221. [PMID: 25604164 DOI: 10.1007/10_2014_299] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Solid-state fermentation (SSF) with filamentous fungi is a promising technique for the production of a range of biotechnological products and has the potential to play an important role in future biorefineries. The performance of such processes is intimately linked with the mycelial mode of growth of these fungi: Not only is the production of extracellular enzymes related to morphological characteristics, but also the mycelium can affect bed properties and, consequently, the efficiency of heat and mass transfer within the bed. A mathematical model that describes the development of the fungal mycelium in SSF systems at the particle scale would be a useful tool for investigating these phenomena, but, as yet, a sufficiently complete model has not been proposed. This review presents the biological and mass transfer phenomena that should be included in such a model and then evaluates how these phenomena have been modeled previously in the SSF and related literature. We conclude that a discrete lattice-based model that uses differential equations to describe the mass balances of the components within the system would be most appropriate and that mathematical expressions for describing the individual phenomena are available in the literature. It remains for these phenomena to be integrated into a complete model describing the development of fungal mycelia in SSF systems.
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Affiliation(s)
- Maura Harumi Sugai-Guérios
- Departamento de Engenharia Química e Engenharia de Alimentos, Universidade Federal de Santa Catarina, Centro Tecnológico, Cx.P. 476, Florianópolis, 88040-900, Santa Catarina, Brazil
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16
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ten Buren EBJ, Karrenbelt MAP, Lingemann M, Chordia S, Deng Y, Hu J, Verest JM, Wu V, Gonzalez TJB, van Heck RGA, Odoni DI, Schonewille T, van der Straat L, de Graaff LH, van Passel MWJ. Toolkit for visualization of the cellular structure and organelles in Aspergillus niger. ACS Synth Biol 2014; 3:995-8. [PMID: 25524108 DOI: 10.1021/sb500304m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aspergillus niger is a filamentous fungus that is extensively used in industrial fermentations for protein expression and the production of organic acids. Inherent biosynthetic capabilities, such as the capacity to secrete these biomolecules in high amounts, make A. niger an attractive production host. Although A. niger is renowned for this ability, the knowledge of the molecular components that underlie its production capacity, intercellular trafficking processes and secretion mechanisms is far from complete. Here, we introduce a standardized set of tools, consisting of an N-terminal GFP-actin fusion and codon optimized eforRed chromoprotein. Expression of the GFP-actin construct facilitates visualization of the actin filaments of the cytoskeleton, whereas expression of the chromoprotein construct results in a clearly distinguishable red phenotype. These experimentally validated constructs constitute the first set of standardized A. niger biomarkers, which can be used to study morphology, intercellular trafficking, and secretion phenomena.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mark W. J. van Passel
- Laboratory
for Zoonoses and Environmental Microbiology, Centre for Infectious
Disease Control Netherlands, National Institute of Public Health and the Environment (RIVM), 3720 BA Bilthoven, The Netherlands
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17
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van Munster JM, Nitsche BM, Krijgsheld P, van Wijk A, Dijkhuizen L, Wösten HA, Ram AF, van der Maarel MJEC. Chitinases CtcB and CfcI modify the cell wall in sporulating aerial mycelium of Aspergillus niger. Microbiology (Reading) 2013; 159:1853-1867. [DOI: 10.1099/mic.0.067967-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Jolanda M. van Munster
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Benjamin M. Nitsche
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Kluyver Centre for Genomics of Industrial Fermentation, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Pauline Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Alle van Wijk
- Aquatic Biotechnology and Bioproduct Engineering Department, Institute for Technology and Management (ITM), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Lubbert Dijkhuizen
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Han A. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Arthur F. Ram
- Institute of Biology Leiden, Molecular Microbiology and Biotechnology, Kluyver Centre for Genomics of Industrial Fermentation, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Marc J. E. C. van der Maarel
- Aquatic Biotechnology and Bioproduct Engineering Department, Institute for Technology and Management (ITM), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Microbial Physiology Research Group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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18
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Abadeh A, Lew RR. Mass flow and velocity profiles in Neurospora hyphae: partial plug flow dominates intra-hyphal transport. MICROBIOLOGY-SGM 2013; 159:2386-2394. [PMID: 23970568 DOI: 10.1099/mic.0.071191-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Movement of nuclei, mitochondria and vacuoles through hyphal trunks of Neurospora crassa were vector-mapped using fluorescent markers and green fluorescent protein tags. The vectorial movements of all three were strongly correlated, indicating the central role of mass (bulk) flow in cytoplasm movements in N. crassa. Profiles of velocity versus distance from the hyphal wall did not match the parabolic shape predicted by the ideal Hagen-Poiseuille model of flow at low Reynolds number. Instead, the profiles were flat, consistent with a model of partial plug flow due to the high concentration of organelles in the flowing cytosol. The intra-hyphal pressure gradients were manipulated by localized external osmotic treatments to demonstrate the dependence of velocity (and direction) on pressure gradients within the hyphae. The data support the concept that mass transport, driven by pressure gradients, dominates intra-hyphal transport. The transport occurs by partial plug flow due to the organelles in the cytosol.
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Affiliation(s)
- Aryan Abadeh
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Roger R Lew
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
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19
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Wösten HAB, van Veluw GJ, de Bekker C, Krijgsheld P. Heterogeneity in the mycelium: implications for the use of fungi as cell factories. Biotechnol Lett 2013; 35:1155-64. [PMID: 23592308 DOI: 10.1007/s10529-013-1210-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/05/2013] [Indexed: 11/29/2022]
Abstract
Fungi are widely used as cell factories for the production of pharmaceutical compounds, enzymes and metabolites. Fungi form colonies that consist of a network of hyphae. During the last two decades it has become clear that fungal colonies within a liquid culture are heterogeneous in size and gene expression. Heterogeneity in growth, secretion, and RNA composition can even be found between and within zones of colonies. These findings imply that productivity in a bioreactor may be increased by reducing the heterogeneity within the culture. The results also imply that molecular mechanisms underlying productivity of fungi in bioreactors should not be studied at the culture level but at the level of micro-colony populations or even at zonal or hyphal level.
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Affiliation(s)
- Han A B Wösten
- Department of Microbiology, Kluyver Centre for Genomics of Industrial Fermentation Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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20
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van Leeuwen M, Krijgsheld P, Bleichrodt R, Menke H, Stam H, Stark J, Wösten H, Dijksterhuis J. Germination of conidia of Aspergillus niger is accompanied by major changes in RNA profiles. Stud Mycol 2013; 74:59-70. [PMID: 23449598 PMCID: PMC3563291 DOI: 10.3114/sim0009] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The transcriptome of conidia of Aspergillus niger was analysed during the first 8 h of germination. Dormant conidia started to grow isotropically two h after inoculation in liquid medium. Isotropic growth changed to polarised growth after 6 h, which coincided with one round of mitosis. Dormant conidia contained transcripts from 4 626 genes. The number of genes with transcripts decreased to 3 557 after 2 h of germination, after which an increase was observed with 4 780 expressed genes 8 h after inoculation. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. The correlation coefficient between the RNA profiles of 0 h and 8 h was 0.46. They were between 0.76-0.93 when profiles of 2, 4 and 6 h were compared with that of 8 h. Dormant conidia were characterised by high levels of transcripts of genes involved in the formation of protecting components such as trehalose, mannitol, protective proteins (e.g. heat shock proteins and catalase). Transcripts belonging to the Functional Gene Categories (FunCat) protein synthesis, cell cycle and DNA processing and respiration were over-represented in the up-regulated genes at 2 h, whereas metabolism and cell cycle and DNA processing were over-represented in the up-regulated genes at 4 h. At 6 h and 8 h no functional gene classes were over- or under-represented in the differentially expressed genes. Taken together, it is concluded that the transcriptome of conidia changes dramatically during the first two h and that initiation of protein synthesis and respiration are important during early stages of germination.
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Affiliation(s)
- M.R. van Leeuwen
- Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - P. Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Molecular Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - R. Bleichrodt
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Molecular Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - H. Menke
- DSM Food Specialties, PO Box 1, 2600 MA Delft, The Netherlands
| | - H. Stam
- DSM Food Specialties, PO Box 1, 2600 MA Delft, The Netherlands
| | - J. Stark
- DSM Food Specialties, PO Box 1, 2600 MA Delft, The Netherlands
| | - H.A.B. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Molecular Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - J. Dijksterhuis
- Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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21
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Krijgsheld P, Bleichrodt R, van Veluw G, Wang F, Müller W, Dijksterhuis J, Wösten H. Development in Aspergillus. Stud Mycol 2013; 74:1-29. [PMID: 23450714 PMCID: PMC3563288 DOI: 10.3114/sim0006] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The genus Aspergillus represents a diverse group of fungi that are among the most abundant fungi in the world. Germination of a spore can lead to a vegetative mycelium that colonizes a substrate. The hyphae within the mycelium are highly heterogeneous with respect to gene expression, growth, and secretion. Aspergilli can reproduce both asexually and sexually. To this end, conidiophores and ascocarps are produced that form conidia and ascospores, respectively. This review describes the molecular mechanisms underlying growth and development of Aspergillus.
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Affiliation(s)
- P. Krijgsheld
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - R. Bleichrodt
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - G.J. van Veluw
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - F. Wang
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - W.H. Müller
- Biomolecular Imaging, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - J. Dijksterhuis
- Applied and Industrial Mycology, CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - H.A.B. Wösten
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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22
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PREFACE. Stud Mycol 2013. [DOI: 10.1016/s0166-0616(14)60082-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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23
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van Veluw GJ, Teertstra WR, de Bekker C, Vinck A, van Beek N, Muller WH, Arentshorst M, van der Mei HC, Ram AFJ, Dijksterhuis J, Wösten HAB. Heterogeneity in liquid shaken cultures of Aspergillus niger inoculated with melanised conidia or conidia of pigmentation mutants. Stud Mycol 2012; 74:47-57. [PMID: 23449476 PMCID: PMC3563290 DOI: 10.3114/sim0008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Black pigmented conidia of Aspergillus niger give rise to micro-colonies when incubated in liquid shaken medium. These micro-colonies are heterogeneous with respect to gene expression and size. We here studied the biophysical properties of the conidia of a control strain and of strains in which the fwnA, olvA or brnA gene is inactivated. These strains form fawn-, olive-, and brown-coloured conidia, respectively. The ΔolvA strain produced larger conidia (3.8 μm) when compared to the other strains (3.2-3.3 μm). Moreover, the conidia of the ΔolvA strain were highly hydrophilic, whereas those of the other strains were hydrophobic. The zeta potential of the ΔolvA conidia in medium was also more negative when compared to the control strain. This was accompanied by the near absence of a rodlet layer of hydrophobins. Using the Complex Object Parametric Analyzer and Sorter it was shown that the ratio of individual hyphae and micro-colonies in liquid shaken cultures of the deletion strains was lower when compared to the control strain. The average size of the micro-colonies of the control strain was also smaller (628 μm) than that of the deletion strains (790-858 μm). The size distribution of the micro-colonies of the ΔfwnA strain was normally distributed, while that of the other strains could be explained by assuming a population of small and a population of large micro-colonies. In the last set of experiments it was shown that relative expression levels of gpdA, and AmyR and XlnR regulated genes correlate in individual hyphae at the periphery of micro-colonies. This indicates the existence of transcriptionally and translationally highly active and lowly active hyphae as was previously shown in macro-colonies. However, the existence of distinct populations of hyphae with high and low transcriptional and translational activity seems to be less robust when compared to macro-colonies grown on solid medium.
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Affiliation(s)
- G J van Veluw
- Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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