Multimodal correlative imaging and modelling of phosphorus uptake from soil by hyphae of mycorrhizal fungi.


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Authors
Keyes, Sam 
van Veelen, Arjen 
McKay Fletcher, Dan  ORCID logo  https://orcid.org/0000-0001-6569-2931
Scotson, Callum 
Koebernick, Nico 
Abstract

Phosphorus (P) is essential for plant growth. Arbuscular mycorrhizal fungi (AMF) aid its uptake by acquiring P from sources distant from roots in return for carbon. Little is known about how AMF colonise soil pore-space, and models of AMF-enhanced P-uptake are poorly validated. We used synchrotron X-ray computed tomography to visualize mycorrhizas in soil and synchrotron X-ray fluorescence/X-ray absorption near edge structure (XRF/XANES) elemental mapping for P, sulphur (S) and aluminium (Al) in combination with modelling. We found that AMF inoculation had a suppressive effect on colonisation by other soil fungi and identified differences in structure and growth rate between hyphae of AMF and nonmycorrhizal fungi. Our results showed that AMF co-locate with areas of high P and low Al, and preferentially associate with organic-type P species over Al-rich inorganic P. We discovered that AMF avoid Al-rich areas as a source of P. Sulphur-rich regions were found to be correlated with higher hyphal density and an increased organic-associated P-pool, whilst oxidized S-species were found close to AMF hyphae. Increased S oxidation close to AMF suggested the observed changes were microbiome-related. Our experimentally-validated model led to an estimate of P-uptake by AMF hyphae that is an order of magnitude lower than rates previously estimated - a result with significant implications for the modelling of plant-soil-AMF interactions.

Description

Funder: U.S. Department of Energy through the LANL/LDRD Program


Funder: G. T. Seaborg Institute

Keywords
X-ray computed tomography, X-ray fluorescence, mycorrhizas, plant phosphorus uptake, rhizosphere modelling, synchrotron, Fungi, Hyphae, Mycorrhizae, Phosphorus, Plant Roots, Soil, Soil Microbiology
Journal Title
New Phytol
Conference Name
Journal ISSN
0028-646X
1469-8137
Volume Title
Publisher
Wiley
Sponsorship
NERC (NE/L00237/1)
H2020 European Research Council (646809‐DIMR)
Biotechnology and Biological Sciences Research Council (BB/L02620/1, BB/L502625/1, BB/P004180/1, BB/N013387/1, BB/R017859/1)
EPSRC (EP/M020355/1)