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Živanović BD, Ullrich K, Spasić SZ, Galland P. Auxin- and pH-induced guttation in Phycomyces sporangiophores: relation between guttation and diminished elongation growth. PROTOPLASMA 2023; 260:1109-1133. [PMID: 36622433 DOI: 10.1007/s00709-022-01833-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 12/22/2022] [Indexed: 06/07/2023]
Abstract
Guttation, the formation of exudation water, is widespread among plants and fungi, yet the underlying mechanisms remain largely unknown. We describe the conditions for inducing guttation in sporangiophores of the mucoracean fungus, Phycomyces blakesleeanus. Cultivation on peptone-enriched potato dextrose agar elicits vigorous guttation mainly below the apical growing zone, while sporangiophores raised on a glucose-mineral medium manifest only moderate guttation. Mycelia do not guttate irrespective of the employed media. The topology of guttation droplets allows identifying the non-growing part of the sporangiophore as a guttation zone, which responds to humidity and medium composition in ways that become relevant for turgor homeostasis and thus the sensor physiology of the growing zone. Apparently, the entire sporangiophore, rather than exclusively the growing zone, participates in signal reception and integration to generate a common growth output. Exogenous auxin applied to the growing zones elicits two correlated responses: (i) formation of guttation droplets in the growing and transition zones below the sporangium and (ii) a diminution of the growth rate. In sporangiophore populations, guttation-induction by exogenous control buffer occurs at low frequencies; the bias for guttation increases with increasing auxin concentration. Synthetic auxins and the transport inhibitor NPA suppress guttation completely, but leave growth rates largely unaffected. Mutants C2 carA and C148 carA madC display higher sensitivities for auxin-induced guttation compared to wild type. A working model for guttation includes aquaporins and mechanosensitive ion channels that we identified in Phycomyces by sequence domain searches.
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Affiliation(s)
- Branka D Živanović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
| | - Kristian Ullrich
- Max Planck Institute for Evolutionary Biology, Department of Evolutionary Biology, August Thienemann Str. 2, 24306, Plön, Germany
| | - Sladjana Z Spasić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia
- Singidunum University, Danijelova 32, 11010, Belgrade, Serbia
| | - Paul Galland
- Faculty of Biology, Philipps-University Marburg, Karl-Von-Frisch Str. 8, 35032, Marburg, Germany
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Živanović BD, Luković JD, Korać A, Stanić M, Spasić SZ, Galland P. Signal transduction in Phycomyces sporangiophores: columella as a novel sensory organelle mediating auxin-modulated growth rate and membrane potential. PROTOPLASMA 2022; 259:917-935. [PMID: 34595603 DOI: 10.1007/s00709-021-01709-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
The growing zone (GZ) of the unicellular coenocytic sporangiophore of Phycomyces blakesleeanus represents the site of stimulus reception (light, gravity, gas) and stimulus response, i.e., local modulations of the elongation growth, which may result, in dependence of the stimulus direction, in tropic bending. Until now, evidence for a possible participation of the columella in sensory reception is absent. We confirm with light microscopy earlier studies that show that the GZ and the columella are not separated by a membrane or cell wall, but rather form a spatial continuum that allows free exchange of cytoplasm and organelle transport. Evidence is presented that the columella is responsive to external stimuli. Columellae, from which spores and sporangial cell wall had been removed, respond to exogenous auxin with a local depolarization of the membrane potential and an increased growth rate of the GZ. In contrast, auxin applied to the GZ causes a decrease of the growth rate irrespective of the presence or absence of sporangia. The response pattern is specific and relevant for the sensory reception of Phycomyces, because the light-insensitive mutant C148carAmadC, which lacks the RAS-GAP protein MADC, displays abnormal IAA sensitivity and membrane depolarization. We argue that the traditional concept of the GZ as the only stimulus-sensitive zone should be abandoned in favor of a model in which GZ and columella operate as a single entity capable to orchestrate a multitude of stimulus inputs, including auxin, to modulate the membrane potential and elongation growth of the GZ.
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Affiliation(s)
- Branka D Živanović
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia.
- School of Land and Food, University of Tasmania, Private Bag 54, Hobart, TAS, 7001, Australia.
| | - Jelena Danilović Luković
- Institute for Application of Nuclear Energy, University of Belgrade, Banatska 31b, 11080, Belgrade-Zemun, Serbia
| | - Aleksandra Korać
- Faculty of Biology, University of Belgrade, Studentski trg 16, 11000, Belgrade, Serbia
| | - Marina Stanić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia
| | - Sladjana Z Spasić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, 11030, Belgrade, Serbia
- Singidunum University, Danijelova 32, Belgrade, Serbia
| | - Paul Galland
- Faculty of Biology, Philipps-University Marburg, Karl-von-Frisch Str. 8, 35032, Marburg, Germany
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Abstract
It has previously been reported that in ex vivo planar explants prepared from Xenopus laevis embryos, the intracellular pH (pHi) increases in cells of the dorsal ectoderm from stage 10.5 to 11.5 (i.e. 11-12.5 hpf). It was proposed that such increases (potentially due to H+ being extruded, sequestered, or buffered in some manner), play a role in regulating neural induction. Here, we used an extracellular ion-selective electrode to non-invasively measure H+ fluxes at eight locations around the equatorial circumference of intact X. laevis embryos between stages 9-12 (˜7-13.25 hpf). We showed that at stages 9-11, there was a small H+ efflux recorded from all the measuring positions. At stage 12 there was a small, but significant, increase in the efflux of H+ from most locations, but the efflux from the dorsal side of the embryo was significantly greater than from the other positions. Embryos were also treated from stages 9-12 with bafilomycin A1, to block the activity of the ATP-driven H+ pump. By stage 22 (24 hpf), these embryos displayed retarded development, arresting before the end of gastrulation and therefore did not display the usual anterior and neural structures, which were observed in the solvent-control embryos. In addition, expression of the early neural gene, Zic3, was absent in treated embryos compared with the solvent controls. Together, our new in vivo data corroborated and extended the earlier explant-derived report describing changes in pHi that were suggested to play a role during neural induction in X. laevis embryos.
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Naranjo‐Ortiz MA, Gabaldón T. Fungal evolution: cellular, genomic and metabolic complexity. Biol Rev Camb Philos Soc 2020; 95:1198-1232. [PMID: 32301582 PMCID: PMC7539958 DOI: 10.1111/brv.12605] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/13/2022]
Abstract
The question of how phenotypic and genomic complexity are inter-related and how they are shaped through evolution is a central question in biology that historically has been approached from the perspective of animals and plants. In recent years, however, fungi have emerged as a promising alternative system to address such questions. Key to their ecological success, fungi present a broad and diverse range of phenotypic traits. Fungal cells can adopt many different shapes, often within a single species, providing them with great adaptive potential. Fungal cellular organizations span from unicellular forms to complex, macroscopic multicellularity, with multiple transitions to higher or lower levels of cellular complexity occurring throughout the evolutionary history of fungi. Similarly, fungal genomes are very diverse in their architecture. Deep changes in genome organization can occur very quickly, and these phenomena are known to mediate rapid adaptations to environmental changes. Finally, the biochemical complexity of fungi is huge, particularly with regard to their secondary metabolites, chemical products that mediate many aspects of fungal biology, including ecological interactions. Herein, we explore how the interplay of these cellular, genomic and metabolic traits mediates the emergence of complex phenotypes, and how this complexity is shaped throughout the evolutionary history of Fungi.
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Affiliation(s)
- Miguel A. Naranjo‐Ortiz
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
| | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
- Department of Experimental Sciences, Universitat Pompeu Fabra (UPF)Dr. Aiguader 88, 08003BarcelonaSpain
- ICREAPg. Lluís Companys 23, 08010BarcelonaSpain
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Ren W, Chang H, Li L, Teng Y. Effect of Graphene Oxide on Growth of Wheat Seedlings: Insights from Oxidative Stress and Physiological Flux. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 105:139-145. [PMID: 32458034 DOI: 10.1007/s00128-020-02888-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
In this study, the responses of wheat seedlings to graphene oxide (GO) were investigated at a wide concentration range of 0-1000 mg L-1, including oxidative stress, real-time membrane potential as well as proton and calcium ion fluxes. The results show that GO induced a hormesis effect on root growth (low concentration (100 mg L-1) promotion and high concentration (1000 mg L-1) inhibition. Oxidative stress was responsible for the growth inhibition at GO concentration of 1000 mg L-1, as suggested from great stimulation in the activities of antioxidant enzymes and MDA content in roots or leaves. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) activities were highly correlated with MDA levels (r2 = 0.963, 0.984, and 0.960, respectively). GO exposure caused significant concentration-dependent membrane depolarization in roots, and significantly inhibited H+ efflux and extracellular Ca2+ influx in root cap.
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Affiliation(s)
- Wenjie Ren
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Haiwei Chang
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Lina Li
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- Yunnan Institute of Environmental Science, Kunming, 650034, China
| | - Ying Teng
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
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Grolig F, Moch J, Schneider A, Galland P. Actin cytoskeleton and organelle movement in the sporangiophore of the zygomycete Phycomyces blakesleeanus. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16 Suppl 1:167-178. [PMID: 23927723 DOI: 10.1111/plb.12065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 05/17/2013] [Indexed: 06/02/2023]
Abstract
Growth, photo- and gravitropism of sporangiophores of the zygomycete Phycomyces blakesleeanus occur within the apical growing zone, a cylindrical structure (diameter about 100 μm) that reaches about 1.5-2.5 mm below the tip and has growth rates up to 50 μm·min(-1) . To better understand morphogenesis and growth of the giant aerial hypha, we investigated with confocal microscopy and inhibitors the actin cytoskeleton and by in-vivo particle tracking the associated organelle movement. We found stage-1 sporangiophores (without sporangium) possess an actin cytoskeleton with polar zonation. (i) In the apex, abundant microfilaments without preferential orientation entangled numerous nuclei as well as a conspicious complex of some 200 lipid globules. Microfilament patches (≈ 1.6-μm diameter) are clustered in the tip and were found in the apical cortex, whereas short, curved microfilament bundles (≈ 2.3-μm long) prevailed in the subapex. (ii) In a transition zone downwards to the shaft, the microfilaments rearranged into a dense mat of longitudinal microfilaments that was parallel close to the periphery but more random towards the cell centre. Numerous microfilament patches were found near the cortex (≈ 10/100 μm(2) ); their number decreased rapidly in the subcortex. In contrast, the short, curved microfilament bundles were found only in the subcortex. (iii) The basal shaft segment of the sporangiophore (with central vacuole) exhibited bidirectional particle movement over long distances (velocity ≈ 2 μm·s(-1) ) along massive longitudinal, subcortical microfilament cables. The zonation of the cytoskeleton density correlated well with the local growth rates at the tip of the sporangiophore, and appears thus as a structural prerequisite for growth and bending.
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Affiliation(s)
- F Grolig
- Fachbereich Biologie, Philipps-Universität Marburg, Marburg, Germany
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Galland P. The sporangiophore of Phycomyces blakesleeanus: a tool to investigate fungal gravireception and graviresponses. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16 Suppl 1:58-68. [PMID: 24373010 DOI: 10.1111/plb.12108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 08/16/2013] [Indexed: 06/03/2023]
Abstract
The giant sporangiophore of the single-celled fungus, Phycomyces blakesleeanus, utilises light, gravity and gases (water and ethylene) as environmental cues for spatial orientation. Even though gravitropism is ubiquitous in fungi (Naturwissenschaftliche Rundschau, 1996, 49, 174), the underlying mechanisms of gravireception are far less understood than those operating in plants. The amenability of Phycomyces to classical genetics and the availability of its genome sequence makes it essential to fill this knowledge gap and serve as a paradigm for fungal gravireception. The physiological phenomena describing the gravitropism of plants, foremost adherence to the so-called sine law, hold even for Phycomyces. Additional phenomena pertaining to gravireception, specifically adherence to the novel exponential law and non-adherence to the classical resultant law of gravitropism, were for the first time investigated for Phycomyces. Sporangiophores possess a novel type of gravisusceptor, i.e. lipid globules that act by buoyancy rather than sedimentation and that are associated with a network of actin cables (Plant Biology, 2013). Gravitropic bending is associated with ion currents generated by directed Ca(2+) and H(+) transport in the growing zone (Annals of the New York Academy of Sciences, 2005, 1048, 487; Planta, 2012, 236, 1817). A set of behavioural mutants with specific defects in gravi- and/or photoreception allowed dissection of the respective transduction chains. The complex phenotypes of these mutants led to abandoning the concept of simple linear transduction chains in favour of interacting networks with molecular modules of physically interacting proteins.
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Affiliation(s)
- P Galland
- Fachbereich Biologie, Philipps-Universität Marburg, Marburg, Germany
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