Vacancies

POST-DOC POSITION IN ELECTROPHYSIOLOGY OF FUNGAL NETWORKS

The Kiers group (Evolutionary Biology, VU University) and Merlin Sheldrake (author of Entangled Life), together with the Shimizu group (Systems Biophysics, AMOLF) in Amsterdam, NL are accepting applications for a post-doctoral researcher with exceptional skills in electrophysiology and biophysics. Applicants should be proficient in programming and data analysis, and ideally be familiar with network and complexity theory. Experience with fungi is not required.

For inquires, please email: toby.kiers@vu.nl

Job / Project Description

Symbiotic fungi are able to integrate information across an immense number of growing tips extending over tens of meters, which are simultaneously connected to multiple plants and engaged in complex trading relationships. How do fungi coordinate rapid responses to external stimuli. In this project, we will test the hypothesis that fungal networks rely on electrical activity (i.e. voltage changes across cell membranes) to respond to nutrient stimuli and communicate with distant parts of their own networks and with their symbiotic plant partners. This project will build on recent developments in the biological sciences which show that ‘nervous system-like’ signaling in plants and nutrient-sensing electrical pulses in bacterial biofilms rely on electrical activity to propagate information. More detailed background to the project is provided in the extended project description below.

The successful applicant will deploy techniques from neuroscience to study fungal networks; fungal cells, like neurones, grow from their tips, form complex networks, and are electrically excitable. These techniques include vibrating microelectrodes, voltage imaging to quantify longer-lived, wave-like activity, and high-density microelectrode arrays to quantify shorter-lived activity. Collectively, these techniques allow us to precisely follow electrical activity in complex symbiotic networks, opening a new field of research into electrical sensing in fungi. The Kiers and Shimizu labs are conducting world-leading research into intra-cellular flows and trading strategies of fungal networks, and the successful applicant will be well-positioned to interpret their findings within these existing experimental and theoretical frameworks with a view to advancing our understanding of fungal network behaviour and communication more generally.

Cross-discipline collaboration

We offer a unique opportunity for a post-doctoral researcher to contribute to cutting-edge research into the behaviour of fungal networks by working at the intersection of microbiology, evolutionary biology, and biophysics. The successful candidate will work with Toby Kiers, Merlin Sheldrake, Vasilis Kokkoris, Pilar Junier and Tom Shimizu to investigate the role of bioelectrical signaling in the development and behaviour of fungal networks, and will be supported by technical staff to propagate and maintain fungal cultures. The project is further supported by the Hefner Foundation and the non-profit SPUN, aimed at accelerating fungal innovation and conservation.

Requirements

  • Candidates should hold a Ph.D. with a strong background in electrophysiology and/or biophysics.
  • Candidates should be skilled in programming and data analysis
  • Outstanding publication record
  • Excellent ability to communicate in both written and spoken English

Experience with fungi is not needed, but any experience in microbiology and living systems is a bonus. Preference will be given to candidates with prior experience with electrophysiological techniques, including the use of voltage sensitive dyes and microelectrode arrays, and those with knowledge of network / complexity theory.

For full details on salary and benefits, see: https://werkenbij.vu.nl/ad/post-doc-position-in-electrophysiology-of-fungal-networks/p3lihm

Applications sent over email will not be accepted.

Extended project description

 The human brain – a complex network of ~100 billion neurons – relies on neural signaling to integrate an electrical ‘symphony’ of input that shapes our behavioral responses to stimuli. But brains are not unique in relying on electrical activity to propagate information: many of their characteristics reflect more ancient processes that existed long before brains evolved. ‘Nervous system-like’ signaling in plants,[1]nutrient-sensing pulses in bacterial biofilms,[2],[3] and rapid coordination of free-living fungal networks using ‘action potential-like’ responses[4],[5] show the precision with which electrical activity can be modulated in brainless organisms.

In fungi, external stimuli – such as exposure to a food source – can drive changes membrane potentials away from steady state values [6]. These changes are then propagated to adjacent cells.[7],[8] This is analogous to the propagation of action potentials along animal neurons. By triggering the depolarization of neighboring cells,[9],[10] electrical activity can drive feedback loops that allow fungus to sense (and rapidly respond) to environmental changes.[11]

Past work has focused exclusively on electrical activity in free-living fungi. However, symbiotic fungal trade networks must integrate an even larger diversity of chemical and physical stimuli – both from the environment and from their host roots – to execute trade decisions.Information must be integrated across an immense number of hyphal tips, which at any one moment can simultaneously be connected to multiple plants, over tens of meters. One report from the 1990s in AM fungi found small currents around germinating spores, and the induction of an inward current where the hyphae connect with host root,[12] suggesting that the fungus can induce electrophysiological changes in host cortical cells at the penetration point. In theory, electrical activity can result in changes in nutrient transfer along hyphae, for example influencing the movement of specific resources, such as negatively-charged polyphosphate granules toward hosts.

Our aim is to capitalize on the rapid advancements in Voltage Imaging and Electrophysiology to study the precise spatial propagation, and spread of electrical activity across fungal networks. We will measure electrical activity using traditional vibrating microelectrodes, as done previously in filamentous fungi.[13] However, because microelectrodes are cumbersome and can cause cellular damage, our main focus is on two techniques that are less invasive, and more sensitive: Voltage imaging (VI) will measure longer-lived (i.e. seconds), wave-like activity moving across networks.[14] Our aim is to use Microelectrode Arrays (MEA) will quantify shorter-lived (i.e. milliseconds) spikes [15]. Collectively, these techniques allow us to precisely follow electrical activity in complex symbiotic networks, opening a new field of research into electrical sensing in fungi.

[1] Muday GK, Brown-Harding H. Nervous system-like signaling in plant defense. Science. 2018; 361: 1068–1069

[2] Stratford JP, Edwards CLA, Ghanshyam MJ, Malyshev D, Delise MA, Hayashi Y, et al. Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity. Proceedings of the National Academy of Sciences of the United States of America. 2019; 116: 9552–9557

[3] Prindle, A., Liu, J., Asally, M., Ly, S., Garcia-Ojalvo, J., & Süel, G. M. Ion channels enable electrical communication in bacterial communities. Nature. 2015: 527, 59-63.

[4] Harold FM, Kropf DL, Caldwell JH. Why do fungi drive electric currents through themselves? Experimental Mycology. 1985; 9: 3–86;

[5] Olsson S, Hansson BS. Action potential-like activity found in fungal mycelia is sensitive to stimulation. Naturwissenschaften. 1995; 82: 30–31

[6] Adamatzky A. On spiking behaviour of oyster fungi Pleurotus djamor. Scientific Reports. 2018; 8: 1–7

[7] Gow NAR, Morris BM. The electric fungus. Botanical Journal of Scotland. 1995; 47: 263–277

[8] Olsson S, Hansson BS. Action potential-like activity found in fungal mycelia is sensitive to stimulation. Naturwissenschaften. 1995; 82: 30–31

[9] Harold FM, Kropf DL, Caldwell JH. Why do fungi drive electric currents through themselves? Experimental Mycology. 1985; 9: 3–86

[10] Gow NAR. Transhyphal electrical currents in fungi. Journal of General Microbiology. 1984; 130: 3313–3318

[11] Olsson S. Nutrient translocation and electrical signalling in mycelia. In: Gow NAR, Robson GD, Gadd GM (eds). The Fungal Colony. 1999. Cambridge University Press, Cambridge, pp 25–48.

[12] Berbara RLL, Morris BM, Fonesca HMAC, Reid, B.Gow NAR, Daft MJ. Electrical currents associated with arbuscular mycorrhizal interactions. New Phytologist. 1995; 129: 433–438

[13] Berbara RLL, Morris BM, Fonesca HMAC, Reid, B.Gow NAR, Daft MJ. Electrical currents associated with arbuscular mycorrhizal interactions. New Phytologist. 1995; 129: 433–438

[14] Prindle A, Liu J, Asally M, Ly S, Garcia-Ojalvo J, Süel GM. Ion channels enable electrical communication in bacterial communities. Nature. 2015; 527: 59–63

[15] Obien MEJ, Deligkaris K, Bullmann T, Bakkum DJ, Frey U. Revealing neuronal function through microelectrode array recordings. Frontiers in Neuroscience. 2015; 9: 423

 

Master’s students

We welcome Master’s students who would like to join our lab for 6-9 month internships focused on rhizosphere mutualisms.

If you are interested in joining the lab as a Phd student or a Post-doc, please inquire about potential fellowship opportunities.

Information: toby.kiers@vu.nl