Dataset DOI: 10.5061/dryad.j3tx95xz7

Description of the data and file structure

Data for Figures 3 and 4: Mucoromycotina fine root endophyte engages in a nutritionally mutualistic symbiosis with Arabidopsis thaliana

Principle Investigator Contact Information:

Name: Katie Field  

Institution: University of Sheffield

Email: k.j.field@sheffield.ac.uk

Alternate Contact Information:

Name: Jurriaan Ton

Institution: University of Sheffield

Email: j.ton@sheffield.ac.uk

Dataset Overview

This dataset contains the shoot biomass, carbon-transfer, and nutrient (¹⁵N and ³³P) tracer data underpinning Figures 3 and 4 of Prout et al., 2026 (in press). Arabidopsis thaliana is widely considered incapable of forming mycorrhizal associations. Here, we show that a wild-isolated Mucoromycotina 'fine root endophyte' (MFRE) strain, Lyc-1, colonises Arabidopsis roots under monoaxenic conditions without affecting plant growth, and that this association involves bi-directional carbon and nutrient exchanges between host and fungus. Figure 3 presents shoot biomass data comparing MFRE-inoculated and uninoculated Arabidopsis plants, alongside quantification of plant-fixed carbon (derived from a ¹⁴CO₂ pulse-label) recovered from the growth medium of inoculated (intact hyphae) versus uninoculated microcosms. Figure 4 presents shoot nitrogen content and tracer-derived ¹⁵N and ³³P content of Arabidopsis shoots across three treatment groups: MFRE-inoculated plants with intact extraradical hyphae, MFRE-inoculated plants with severed (trenched) extraradical hyphae, and non-fungal (uninoculated) controls, demonstrating fungal-mediated nutrient transfer to the host plant.

Dates of Data Collection

Isotope labelling and tissue harvest: 2024

Scintillation counting and IRMS analysis: 2024

Data Spatial Scope:  Not applicable - data were generated from controlled, monoaxenic laboratory microcosms (Arabidopsis thaliana Col-0 co-cultured with MFRE isolate Lyc-1 on ½GB5 agar plates) rather than from field sampling.

Funding

ERC CoG 865225

ERC Adv 101199639

Royal Society Faraday Discovery Fellowship FDF/S2/251044

BBSRC BB/W015250/1

Sharing/Access

This work is licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license.

Files and variables

Description of the data and file structure

This dataset comprises two Excel workbooks, each containing a single worksheet of the data underlying one figure. Missing data are coded as blank cells. Sample sizes and treatment groupings match those described in the Methods (STAR Methods, "¹⁵N, ³³P, and ¹⁴C Isotope tracing").

Files and Folders

Data_for_Figure_3.xlsx (sheet "Figure 3") This file contains two independent datasets, arranged as separate column blocks, underlying the two panels of Figure 3.

Block 1 (columns A–B): Shoot biomass: Compares shoot dry biomass of MFRE-inoculated versus uninoculated Arabidopsis plants, demonstrating that MFRE colonisation does not adversely affect plant growth. Treatment:  Fungal inoculation status of the plant. "Inoculated" = co-cultured with MFRE isolate Lyc-1; "Uninoculated" = non-fungal control.    Shoot biomass (mg): (numeric) Dry shoot biomass of an individual plant, in milligrams. Number of rows: 43 (Inoculated, n = 32; Uninoculated, n = 11)

Block 2 (columns D–E): Plant-fixed carbon recovered from growth medium: Quantifies transfer of photosynthetically-fixed carbon (from a ¹⁴CO₂ pulse-label) from the plant into the growth medium, comparing microcosms with an intact MFRE mycelial connection against non-fungal controls (see Methods, "Quantification of C, ³³P, and ¹⁵N fluxes").    Treatment: Treatment group. "Inoculated, intact hyphae" = MFRE-inoculated plants with the extraradical mycelial network left undisturbed; "Uninoculated" = non-fungal control.    Plant-fixed C in growth medium (ng): (numeric) Mass of  plant-fixed carbon recovered from the growth medium of each microcosm, in nanograms, determined by sample oxidation and liquid scintillation counting.

Data_for_Figure_4.xlsx (sheet "Figure 4") This file contains shoot nitrogen content and tracer-derived (¹⁵N, ³³P) shoot nutrient content for Arabidopsis plants across three treatment groups, underpinning Figure 4.

Treatment groups follow the isotope-tracing microcosm design described in the Methods: "Intact hyphae" plates retained a continuous extraradical MFRE mycelium; "Trenched hyphae" plates had the extraradical mycelium severed; "Non-fungal" plates lacked MFRE inoculation entirely. Sample type: Treatment group. "Inoculated, intact hyphae"; "Inoculated, trenched hyphae"; "Uninoculated" (non-fungal control). Total shoot N content (ug): Total nitrogen content of shoot tissue, in micrograms, calculated from shoot dry biomass and %N (Methods equation: N = Biomass × (%N/100)).  Shoot N concentration (ug mg dw): Nitrogen concentration per milligram dry weight of shoot tissue, in micrograms. Total shoot ¹⁵N (ng): Excess, tracer-derived ¹⁵N mass in shoot tissue, in nanograms, calculated relative to unlabelled control plants and quantified by continuous-flow isotope ratio mass spectrometry (IRMS). Negative values arise from samples with natural-abundance ¹⁵N below that of the unlabelled reference controls and are retained rather than truncated at zero. Shoot [^15^N] (ng mg dw): Concentration of tracer-derived ¹⁵N per milligram dry weight of shoot tissue, in nanograms. Shoot ³³P (pg): Total mass of ³³P tracer recovered in shoot tissue, in picograms, determined by acid digestion and liquid scintillation counting (Methods equation for M³³P). Shoot [^33^P] (pg mg dw): (numeric) Concentration of ³³P tracer per milligram dry weight of shoot tissue, in picograms.

Code/software

Any program that will open a spreadsheet, such as Excel is recommended.

Data Sources

Data were generated by the authors from monoaxenic Arabidopsis thaliana (Col-0) - MFRE (Lyc-1) co-culture microcosms, using isotope pulse-labelling (¹⁵N-ammonium chloride, ³³P-orthophosphate, ¹⁴CO₂), liquid scintillation counting, sample oxidation, and continuous-flow isotope ratio mass spectrometry (IRMS), as described in the Methods of the associated manuscript.