DOI: 10.5061/dryad.pc866t1ww
title: Fungal symbiont diversity drives growth of Holcus lanatus depending on soil nutrient availability

description: Arbuscular mycorrhizal (AM) fungi frequently colonise plant roots and can
 affect plant morphology and physiology through their contribution to plant
 nutrition. However, the functional role of AM fungi in the presence of
 other microbial symbionts, including widespread Mucoromycotina ‘fine root
 endophytes’ (MFRE) fungi, remains largely unknown. While both AM fungi and
 MFRE transfer nutrients, including nitrogen, from inorganic and organic
 sources to host plants, their combined effects on co-colonised plants have
 only been investigated in liverworts. Here, we compare the morphology and
 physiology of the grass Holcus lanatus grown with an AM fungal
 community versus a more diverse symbiotic fungal community containing both
 AM fungi and MFRE.  Holcus lanatus plants were grown in the
 presence of either a diverse MFRE+AM fungi soil inoculum or a
 multi-species AM fungal inoculum. Plant traits associated with growth were
 quantified, along with fungal transfer of 15N tracer to plants from a
 variety of sources (ammonium chloride, alanine, glycine, algal
 necromass).  Holcus lanatus grown with the AM fungal community
 had greater root and shoot growth during early development and prior to
 the addition of 15N-labelled sources, compared to plants grown with the
 more diverse symbiotic fungal community. When nitrogen sources were made
 available to the fungal symbionts in the pot microcosms, plants growing
 with the MFRE+AM fungi soil inoculum had a faster growth rate than plants
 growing with the AM fungal community. At harvest, H. lanatus grown with
 the AM fungal community had a larger biomass and there were no differences
 in 15N tracer assimilation in plants across the two fungal community
 treatments. Our results demonstrate that the diversity of fungal inocula
 in conjunction with soil nutrient availability determines the benefits
 derived by plants from diverse fungal symbionts. Our research contributes
 to understanding host plant outcomes in diverse multi-symbiont scenarios.
description: The dataset was collected from a single pot experiment using
 measurements taken by hand/through observation or using specialist
 equipment. A detailed account is provided:  
 Fungal colonisation data – harvested root material was mounted
 on microscope slides and fungal structures were quantified manually under
 a compound microscope through observation. Hyphal
 length data – isolated fungal hyphae from soil were mounted on microscope
 slides and fungal structures were quantified manually under a compound
 microscope through observation. Biomasses – harvested
 material was weighed on electronic scales. Number of
 Tillers – plant tillers were quantified weekly through counting by
 hand. Number of Leaves – plant leaves were quantified
 weekly through counting by hand. Maximum Canopy
 Height & RGR – the height of the tallest leaf was measured weekly
 using hand-held callipers. From this data, the relative growth rate per
 pot was determined (see equations within Excel sheet).
 Chlorophyll content (SPAD) – relative chlorophyll content from
 the tallest leaf was measured using a hand-held Minolta SPAD
 meter. <sup>15</sup>N and N in shoots ­–
 shoot material was analysed using isotope ratio mass spectrometry (IRMS)
 to produce values for %N, <sup>15</sup>N Atom % and
 <sup>15</sup>N Delta Air, which were then processed with the
 recorded biomass data to give absolute and concentration data for
 nitrogen. All steps are detailed in the Excel sheet. 
 <sup>15</sup>N and N in roots ­– root material was analysed
 using isotope ratio mass spectrometry (IRMS) to produce values for %N,
 <sup>15</sup>N Atom % and <sup>15</sup>N Delta
 Air, which were then processed with the recorded biomass data to give
 absolute and concentration data for nitrogen. All steps are detailed in
 the Excel sheet.
description: # Fungal symbiont diversity drives growth of Holcus lanatus depending on
 soil nutrient availability 
 The dataset contains data collected periodically during the pot experiment
 (Number of Tillers, Number of Leaves, Maximum Canopy Height & RGR,
 Chlorophyll content (SPAD)), and at the endpoint of the experiment (Fungal
 colonisation data, Hyphal length data, Biomasses, 15N and N in shoots, 15N
 and N in roots). Raw and processed data are included. ## Description of
 the data and file structure The dataset was collected from a single pot
 experiment using measurements taken by hand/through observation or using
 specialist equipment. A detailed account of each Excel sheet contained
 within the data file is provided:  ### Sheet 1: Fungal
 colonisation. Number of samples analysed = 48 * Pot ID: pot
 number identifier * Core with isotope tracer: the status (rotated or
 static) of the plastic core containing labelled nutrients that were only
 accessible to fungi. * 15N-labelled source: the nutrient source in each
 pot that was made up of 15N isotope * Fungal Treatment: AM = arbuscular
 mycorrhizal fungal community; MFRE+AM = Mucoromycotina fine root
 endophytes and arbuscular mycorrhizal fungi. * FOV: Fields of View  * MFRE
 COL: Line intersect with MFRE colonisation structures. * AM COL: Line
 intersect with AM colonisation structures.   * % TRL colonisation with
 MFRE: % Total Root Length colonisation with MFRE   * % TRL colonisation
 with AM : % Total Root Length colonisation with AM fungi * MFRE%
 composition: composition of colonising fungi that were MFRE. * AM%
 composition: composition of colonising fungi that were AM fungi. ### Sheet
 2: Hyphal length. Number of samples analysed: 144 * Pot ID & fungal
 treatment: pot number identifier and fungi within the pots, i.e. AM =
 arbuscular mycorrhizal fungal community; MFRE+AM = Mucoromycotina fine
 root endophytes and arbuscular mycorrhizal fungi.   * Rep: Replicate
 number * Fungi quantified: AM = arbuscular mycorrhizal fungi; MFRE =
 Mucoromycotina fine root endophytes * 15N-labelled source: the nutrient
 source in each pot that was made up of 15N isotope. * Pre freeze-dried
 soil FW (g): fresh weight of soil substrate in pot * Post freeze-dried
 soil DW (g): dry weight of soil substrate in pot. * Proportion of dry
 soil: Pot dry weight divided by pot fresh weight. * Bulk soil weighed out
 FW (g) : Fresh weight of soil subsample analysed. * Bulk soil weighed out
 DW (g): Dry weight of soil subsample analysed.      * Sample counts:
 Microscope gridline intersects with fungal structures.         * Fields of
 View : Fields of View examined. * Hyphae per Field of View: hyphae per
 Field of View           * mm hyphae g-1 soil DW: mm hyphae per gram of
 soil dry weight calculated using formula described in Brundrett et al.
 1994.   * m hyphae g-1 soil DW: m hyphae per gram of soil dry weight
         * Pot Average m hyphae per gram of soil DW: average m hyphae per
 gram of soil dry weight for each pot, based on combining the data for the
 two replicates of each pot. ### Sheet 3: Biomasses. Number of
 samples analysed = 96 * Pot ID: pot number identifier * 15N-labelled
 source: the nutrient source in each pot that was made up of 15N isotope *
 Fungal Treatment: AM = arbuscular mycorrhizal fungal community; MFRE+AM =
 Mucoromycotina fine root endophytes and arbuscular mycorrhizal fungi.     
 * Core with isotope tracer: the status (rotated or static) of the plastic
 core containing labelled nutrients that were only accessible to
 fungi.            * Roots fresh weight: total (g): total fresh weight of
 roots * Roots fresh weight: after sampling for root colonisation (g):
 total fresh weight of remaining roots after a subsample was taken for
 colonisation analysis. * Freeze-dried remaining roots (g): dry weight of
 remaining roots after the subsample had been taken         * Roots dry
 weight: total (g): total dry weight of roots, which includes the root
 subsample * Roots dry weight: total (mg): total dry weight of roots *
 Shoot dry weight: total (g): total dry weight of shoots after they were
 freeze-dried. * Root to shoot ratio: root dry weight divided by shoot dry
 weight.    * Bulk pot soil fresh weight: total (g): fresh weight of soil
 substrate in pot * Bulk pot soil dry weight: total (g): dry weight of soil
 substrate in pot          * Core with isotope tracer dry weight: total
 (g): dry weight of soil substrate in core containing labelled nutrients. *
 Core without isotope tracer dry weight: total (g): dry weight of soil
 substrate in core containing no labelled nutrients. ### Sheet 4: Number of
 Tillers. Number of samples analysed = 96 * Pot ID: pot number identifier *
 15N-labelled source: the nutrient source in each pot that was made up of
 15N isotope * Fungal Treatment: AM = arbuscular mycorrhizal fungal
 community; MFRE+AM = Mucoromycotina fine root endophytes and arbuscular
 mycorrhizal fungi.      * Core with isotope tracer: the status (rotated or
 static) of the plastic core containing labelled nutrients that were only
 accessible to fungi.            * Week 2, Week 3, Week 4, Week 5, Week 6,
 Week 7, Week 8, Week 9, Week 10, Week 11: Average number of tillers on a
 plant per pot at each week of growth * Tiller number Change (%): Change in
 the average number of tillers on a plant per pot between Week 8 and Week
 11. ### Sheet 5: Number of Leaves. Number of samples analysed = 96 * Pot
 ID: pot number identifier * 15N-labelled source: the nutrient source in
 each pot that was made up of 15N isotope * Fungal Treatment: AM =
 arbuscular mycorrhizal fungal community; MFRE+AM = Mucoromycotina fine
 root endophytes and arbuscular mycorrhizal fungi.      * Core with isotope
 tracer: the status (rotated or static) of the plastic core containing
 labelled nutrients that were only accessible to fungi.            * Week
 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8, Week 9, Week 10, Week
 11: Average number of leaves on a plant per pot at each week of growth
 * Leaf number Change (%): Change in the average number of
 leaves on a plant per pot between Week 8 and Week 11. ### Sheet 6: Maximum
 Canopy Height & RGR. Number of samples analysed = 96 * Pot
 ID: pot number identifier * 15N-labelled source: the nutrient source in
 each pot that was made up of 15N isotope. * Fungal Treatment: AM =
 arbuscular mycorrhizal fungal community; MFRE+AM = Mucoromycotina fine
 root endophytes and arbuscular mycorrhizal fungi.      * Core with isotope
 tracer: the status (rotated or static) of the plastic core containing
 labelled nutrients that were only accessible to fungi.            * Week
 2, Week 3, Week 4, Week 5, Week 6, Week 7, Week 8, Week 9, Week 10, Week
 11: Tallest Leaf per pot (i.e. Maximum Canopy Height) (mm) at each week of
 growth * Maximum Canopy Height Change (%): Change in the Maximum Canopy
 Height per pot between Week 8 and Week 11.           * Relative growth
 rate at 8 weeks: Relative growth rate at 8 weeks     * Relative growth
 rate at 11 weeks: Relative growth rate at 11 weeks * Change in RGR: Change
 in the Relative growth rate per pot between Week 8 and Week 11.         *
 Change in RGR (with direction of change): number with “-” = decrease in
 RGR; number with “+” = increase in RGR. ### Sheet 7: Chlorophyll content
 (SPAD). Number of samples analysed = 96 * Pot ID: pot number identifier *
 15N-labelled source: the nutrient source in each pot that was made up of
 15N isotope * Fungal Treatment: AM = arbuscular mycorrhizal fungal
 community; MFRE+AM = Mucoromycotina fine root endophytes and arbuscular
 mycorrhizal fungi.      * Core with isotope tracer: the status (rotated or
 static) of the plastic core containing labelled nutrients that were only
 accessible to fungi.            * Week 2, Week 3, Week 4, Week 5, Week 6,
 Week 7, Week 8, Week 9, Week 10, Week 11: Average Minolta SPAD reading
 (chlorophyll content) per pot at each week of growth * Change in
 Chlorophyll Content (%): Change in the average Minolta SPAD reading
 (chlorophyll content) per pot between Week 8 and Week 11. ### Sheet 8: 15N
 and N in shoots. ­ Number of samples analysed = 96 * Rows 2 to 5 contain
 data for control samples (Shoots BLANK), which provide the background 15N
 levels in unlabelled plants. In these rows, cells that fall under columns
 D to G contain data; all other cells in these rows are left intentionally
 blank. * 15N-labelled source: the nutrient source in each pot that was
 made up of 15N isotope. * Fungal Treatment: AM = arbuscular mycorrhizal
 fungal community; MFRE+AM = Mucoromycotina fine root endophytes and
 arbuscular mycorrhizal fungi.      * Core with isotope tracer: the status
 (rotated or static) of the plastic core containing labelled nutrients that
 were only accessible to fungi. * Sample ID: Plant tissue type and pot
 number identifier         * %N: Mass spectrometry output; % nitrogen in
 sample          * 15N Atom %:  Mass spectrometry output; % 15N isotope in
 sample * 15N Delta Air: Mass spectrometry output (not used in paper or
 analyses); a measure of the ratio of the two stable isotopes of nitrogen,
 15N:14N * Atom % Excess: Sample 15N Atom % – average 15N Atom % of shoot
 BLANK samples * total shoot biomass (DW mg): total dry weight of
 shoots      * total shoot biomass (DW g): total dry weight of
 shoots         * mass of N (mg): absolute mass of N in shoot tissues *
 mass of 15N (mg): absolute mass of 15N in shoot tissues                 *
 mass of 15N (ug): absolute mass of 15N in shoot tissues                  *
 concentration of 15N (ug/g shoot DW): concentration of 15N in shoot
 tissues (dry weight) * Fungal-acquired mass of 15N (ug): [mass of 15N in
 shoot tissues for pot with static core] minus [average mass of 15N in
 shoot tissues for pots with rotated cores (shown in bold within column
 O)].   * Fungal-acquired concentration of 15N (ug/g shoot DW):
 Fungal-acquired mass of 15N in shoot tissue divided by total shoot
 biomass. ### Sheet 9: 15N and N in roots. Number of samples analysed = 96
 * Rows 2 to 5 contain data for control samples (Roots BLANK), which
 provide the background 15N levels in unlabelled plants. In these rows,
 cells that fall under columns D to G contain data; all other cells in
 these rows are left intentionally blank. * 15N-labelled source: the
 nutrient source in each pot that was made up of 15N isotope. * Fungal
 Treatment: AM = arbuscular mycorrhizal fungal community; MFRE+AM =
 Mucoromycotina fine root endophytes and arbuscular mycorrhizal fungi.     
 * Core with isotope tracer: the status (rotated or static) of the plastic
 core containing labelled nutrients that were only accessible to fungi. *
 Sample ID: Plant tissue type and pot number identifier         * %N: Mass
 spectrometry output; % nitrogen in sample          * 15N Atom %:  Mass
 spectrometry output; % 15N isotope in sample * 15N Delta Air: Mass
 spectrometry output (not used in paper or analyses); a measure of the
 ratio of the two stable isotopes of nitrogen, 15N:14N * Atom % Excess:
 Sample 15N Atom % – average 15N Atom % of root BLANK samples   * total
 root biomass (DW mg): total dry weight of roots          * total root
 biomass (DW g): total dry weight of roots * mass of N (mg): absolute mass
 of N in root tissues   * mass of 15N (mg): absolute mass of 15N in root
 tissues                   * mass of 15N (ug): absolute mass of 15N in root
 tissues                    * concentration of 15N (ug/g root DW):
 concentration of 15N in root tissues (dry weight) * Fungal-acquired mass
 of 15N (ug): [mass of 15N in root tissues for pot with static core] minus
 [average mass of 15N in root tissues for pots with rotated cores (shown in
 bold within column O)].   * Fungal-acquired concentration of 15N (ug/g
 root DW): Fungal-acquired mass of 15N in root tissue divided by total root
 biomass.