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A major challenge for agriculture is to provide sufficient plant nutrients such as phosphorus (P) to meet the global food demand. The sufficiency of P is a concern because of it's essential role in plant growth, the finite availability of P-rock for fertilizer production and the poor plant availability of soil P. This study investigated whether biofertilizers and bioenhancers, such as arbuscular mycorrhizal fungi (AMF) and their associated bacteria could enhance growth and P uptake in maize. Plants were grown with or without mycorrhizas in compartmented pots with radioactive P tracers and were inoculated with each of 10 selected bacteria isolated from AMF spores. Root colonization by AMF produced large plant growth responses, while seven bacterial strains further facilitated root growth and P uptake by promoting the development of AMF extraradical mycelium. Among the tested strains, Streptomyces sp. W94 produced the largest increases in uptake and translocation of 33 P, while Streptomyces sp. W77 highly enhanced hyphal length specific uptake of 33 P. The positive relationship between AMF-mediated P absorption and shoot P content was significantly influenced by the bacteria inoculants and such results emphasize the potential importance of managing both AMF and their microbiota for improving P acquisition by crops.

Plant interactions with arbuscular mycorrhizal fungi have long attracted interest for their potential to promote more efficient use of mineral resources in agriculture. Their use, however, remains limited by a lack of understanding of the processes that determine the outcome of the symbiosis. In this study, the impact of host genotype on growth response to mycorrhizal inoculation was investigated in a panel of diverse maize lines. A panel of 30 maize lines was evaluated with and without inoculation with arbuscular mycorrhizal fungi. The line Oh43 was identified to show superior response and, along with five other reference lines, was characterized in greater detail in a split-compartment system, using 33 P to quantify mycorrhizal phosphorus uptake. Changes in relative growth indicated variation in host capacity to profit from the symbiosis. Shoot phosphate content, abundance of root-internal and -external fungal structures, mycorrhizal phosphorus uptake, and accumulation of transcripts encoding plant PHT1 family phosphate transporters varied among lines. Superior response in Oh43 is correlated with extensive development of root-external hyphae, accumulation of specific Pht1 transcripts and high phosphorus uptake by mycorrhizal plants. The data indicate that host genetic factors influence fungal growth strategy with an impact on plant performance., (© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.)

Capturing the full growth potential in crops under future elevated CO 2 (eCO 2 ) concentrations would be facilitated by improved understanding of eCO 2 effects on uptake and use of mineral nutrients. This study investigates interactions of eCO 2 , soil phosphorus (P), and arbuscular mycorrhizal (AM) symbiosis in Medicago truncatula and Brachypodium distachyon grown under the same conditions. The focus was on eCO 2 effects on vegetative growth, efficiency in acquisition and use of P, and expression of phosphate transporter (PT) genes. Growth responses to eCO 2 were positive at P sufficiency, but under low-P conditions they ranged from non-significant in M. truncatula to highly significant in B. distachyon Growth of M. truncatula was increased by AM at low P conditions at both CO 2 levels and eCO 2 ×AM interactions were sparse. Elevated CO 2 had small effects on P acquisition, but enhanced conversion of tissue P into biomass. Expression of PT genes was influenced by eCO 2 , but effects were inconsistent across genes and species. The ability of eCO 2 to partly mitigate P limitation-induced growth reductions in B. distachyon was associated with enhanced P use efficiency, and requirements for P fertilizers may not increase in such species in future CO 2 -rich climates., (© The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Two pathways exist for plant Pi uptake from soil: via root epidermal cells (direct pathway) or via associations with arbuscular mycorrhizal (AM) fungi, and the two pathways interact in a complex manner. This study investigated distal and local effects of AM colonization on direct root Pi uptake and root growth, at different soil P levels. Medicago truncatula was grown at three soil P levels in split-pots with or without AM fungal inoculation and where one root half grew into soil labelled with (33)P. Plant genotypes included the A17 wild type and the mtpt4 mutant. The mtpt4 mutant, colonized by AM fungi, but with no functional mycorrhizal pathway for Pi uptake, was included to better understand effects of AM colonization per se. Colonization by AM fungi decreased expression of direct Pi transporter genes locally, but not distally in the wild type. In mtpt4 mutant plants, direct Pi transporter genes and the Pi starvation-induced gene Mt4 were more highly expressed than in wild-type roots. In wild-type plants, less Pi was taken up via the direct pathway by non-colonized roots when the other root half was colonized by AM fungi, compared with non-mycorrhizal plants. Colonization by AM fungi strongly influenced root growth locally and distally, and direct root Pi uptake activity locally, but had only a weak influence on distal direct pathway activity. The responses to AM colonization in the mtpt4 mutant suggested that in the wild type, the increased P concentration of colonized roots was a major factor driving the effects of AM colonization on direct root Pi uptake., (© The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Arbuscular mycorrhizal fungi (AMF) have a key role in plant phosphate (Pi) uptake by their efficient capture of soil phosphorus (P) that is transferred to the plant via Pi transporters in the root cortical cells. The activity of this mycorrhizal Pi uptake pathway is often associated with downregulation of Pi transporter genes in the direct Pi uptake pathway. As the total Pi taken up by the plant is determined by the combined activity of mycorrhizal and direct pathways, it is important to understand the interplay between these, in particular the actual activity of the pathways. To study this interplay we modulated the delivery of Pi via the mycorrhizal pathway in Pisum sativum by two means: (1) Partial downregulation by virus-induced gene silencing of PsPT4, a putative Pi transporter gene in the mycorrhizal pathway. This resulted in decreased fungal development in roots and soil and led to reduced plant Pi uptake. (2) Changing the percentage of AMF-colonized root length by using non-, half-mycorrhizal or full-mycorrhizal split-root systems. The combination of split roots, use of ³²P and ³³P isotopes and partial silencing of PsPT4 enabled us to show that the expression of PsPT1, a putative Pi transporter gene in the direct pathway, was negatively correlated with increasing mycorrhizal uptake capacity of the plant, both locally and systemically. However, transcript changes in PsPT1 were not translated into corresponding, systemic changes in actual direct Pi uptake. Our results suggest that AMF have a limited long-distance impact on the direct pathway., (© 2013 Scandinavian Plant Physiology Society.)

Common mycorrhizal networks (CMNs) influence competition between plants, but reports regarding their precise effect are conflicting. We studied CMN effects on phosphorus (P) uptake and growth of seedlings as influenced by various disruptions of network components. Tomato (Solanum lycopersicon) seedlings grew into established networks of Rhizophagus irregularis and cucumber (Cucumis sativus) in two experiments. One experiment studied seedling uptake of (32)P in the network in response to cutting of cucumber shoots; the other analysed seedling uptake of P and nitrogen (N) in the presence of intact or severed arbuscular mycorrhizal fungus networks and at two soil P concentrations. Pre-established and intact networks suppressed growth of tomato seedlings. Cutting of cucumber shoots mitigated P deficiency symptoms of seedlings, which obtained access to P in the extraradical mycelium and thereby showed improved growth. Solitary seedlings growing in a network patch that had been severed from the CMN also grew much better than seedlings of the corresponding CMN. Interspecific and size-asymmetric competition between plants may be amplified rather than relaxed by CMNs that transfer P to large plants providing most carbon and render small plants P deficient. It is likely that grazing or senescence of the large plants will alleviate the network-induced suppression of seedling growth., (© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.)

Plants colonized by arbuscular mycorrhizal (AM) fungi take up phosphate (Pi)via the mycorrhizal and the direct Pi uptake pathway. Our understanding of the molecular mechanisms involved in the regulation of these pathways is just emerging.Here, we have analyzed the molecular physiology of mycorrhizal Pi uptake in the tomato (Solanum lycopersicum) variety Micro-Tom and integrated the data obtained with studies on chemical signaling in mycorrhiza-inducible Pi transporter gene regulation.At high plant phosphorus (P) status, the mycorrhizal Pi uptake pathway was almost completely repressed and the mycorrhiza-inducible Pi transporter genes were down-regulated. A high plant P status also suppressed the activation of the mycorrhiza-specific StPT3 promoter fragment by phospholipid extracts containing the mycorrhiza signal lysophosphatidylcholine.Our results suggest that the mycorrhizal Pi uptake pathway is controlled at least partially by the plant host. This control involves components in common

Background: Recent studies indicated that arbuscular mycorrhizal fungi (AMF) play important roles in plant accumulation of uranium (U) from contaminated environments, but the impacts of fertilization practices on functioning of the symbiotic associations, which are crucial factors influencing plant nutrition and growth responses to mycorrhiza, have rarely been considered., Materials and Methods: In a greenhouse experiment, a bald root barley mutant (brb) together with the wild type (wt) were used to test the role of root hairs and AMF in uranium (U) uptake by host plants from a U contaminated soil. Nil, 20 and 60 mg KH2PO4-P kg(-1) soil were included to investigate the influences of phosphorus (P) fertilization on plant growth and accumulation of U., Results: Dry matter yield of barley plants increased with increasing P additions and wt produced significantly higher dry weight than brb. Mycorrhiza markedly improved dry matter yield of both genotypes grown at nil P, whereas only brb responded positively to mycorrhiza at 20 mg P kg(-1). At the highest P level, mycorrhiza resulted in growth depressions in both genotypes, except for the roots of wt. In general, plant P concentrations increased markedly with increasing P additions and in response to mycorrhiza. Mycorrhiza and P additions had no significant effects on shoot U concentrations. However, root U concentrations in both genotypes were significantly increased by mycorrhiza. On the other hand, shoot U contents increased with increasing P levels, while 20 mg P kg(-1) stimulated, but 60 mg P kg(-1) marginally affected the U accumulation in roots. Root length specific U uptake was moderately enhanced both by root hairs and strongly enhanced by mycorrhiza. Moreover, non-inoculated plants generally had higher shoot-root ratios of U content than the corresponding inoculated controls., Conclusion: Our study shows that AMF and root hairs improves not only P acquisition but also the root uptake of U, and mycorrhiza generally decreases U translocation from plant root to shoot. Hence, mycorrhiza is of potential use in the phytostabilization of U contaminated environments., Perspectives: The complex impacts of P on U accumulation by barley plants suggested that U behavior in mycorrhizosphere and translocation along the soil-fungi-plant continuum as affected by fertilization practices deserve extensive studies for optimizing the function of mycorrhizal associations for phytoremediation purposes.

Some phosphate rocks (PR) contain high concentrations of uranium (U), which are potentially toxic via accumulation in soils and food chains, and plant uptake of U is likely to be influenced by characteristics of roots and associated microorganisms. The relative importance of root hairs and mycorrhiza in U uptake from PR was studied using a root hairless barley (Hordeum vulgare) mutant (Brb) and its wild type (WT). Both plant genotypes were grown in pots with Glomus intraradices BEG 87, or in the absence of mycorrhiza, and three P treatments were included: nil P, 2% (w/w) PR and 50 mg KH(2)PO(4)-P kg(-1) soil. Mycorrhiza markedly increased d. wts and P contents of Brb amended with nil P or PR, but generally depressed d. wts of WT plants, irrespective of P amendments. Mycorrhiza had contrasting effects on U contents in roots and shoots, in particular in Brb where mycorrhiza increased root U concentrations but decreased U translocation from roots to shoots. The experiment supports our understanding of arbuscular mycorrhiza as being multifunctional by not only improving the utilization of PR by the host plant but also by contributing to the phytostabilization of uranium.

Abstract Biochar (BC) application to soil can potentially replace mineral P fertilizers and its effectiveness as fertilizer can be improved by plant inoculation with the phosphate-solubilizing microorganism Penicillium aculeatum (Pa). Arbuscular mycorrhiza (AM) fungi are important in plant P nutrition and may possibly act synergistically with Pa to improve the uptake of BC-P. Responses in wheat to inoculation with Pa and the AM fungus Rhizophagus irregularis were studied in a pot experiment at two levels of BC fertilization. Pots contained a mesh-enclosed, root free compartment with 33P-labelled soil for assessment of the AM contribution to P uptake and for studying if Pa would affect P uptake by the AM fungal hyphae. AM application suppressed wheat growth, albeit AM pathway had a major role in total P uptake at the two lowest P levels (nil or 20 mg BC-P kg−1 soil). Moreover, AM contribution had similar magnitudes in the presence and absence of Pa. Rhizosphere and bulk soil were actively colonized by Pa, both in the presence and absence of AM. The application of Pa or BC at a low rate increased AM-colonized root lengths. Although this was not translated to increased P uptake by wheat, the results suggest that AM and Pa can be combined without showing antagonistic interactions. However, more work is needed to understand how AM and Pa can be combined to increase plant growth. Highlights • Both the sewage-sludge biochar and the P-solubilizing Penicillium aculeatum enhanced root colonization by mycorrhiza (AM). • AM suppressed wheat growth, but contributed considerably to overall plant P uptake. • Penicillium aculeatum actively colonized both rhizosphere and bulk soil, both in the presence and absence of AM. • AM fungus Rhizophagus irregularis can be combined with P. aculeatum without showing antagonistic interactions. [ABSTRACT FROM AUTHOR]

Plant roots associate with microorganisms to acquire phosphorus (P) from the soil including arbuscular mycorrhizal (AM) fungi and phosphate solubilizers such as yeasts. However, information on interactions between AM fungi and yeasts is limited. The objective of the present study was to examine possible cooperation between the AM fungus Rhizophagus irregularis and the rhizosphere yeasts Cryptococcus flavus and Candida railenensis in terms of maize plant growth and P uptake employing P isotope tracer monitoring. Compartmented growth units with root-hyphal (RHC) and hyphal (HC) mesh bags allowed studying interactions between R. irregularis and yeasts with and without roots. The P isotope dilution method was used to measure possible phosphate solubilization in soil by the rhizosphere yeasts with subsequent P uptake by the AM association. Plants were grown for 8 weeks in low P soil under controlled growth chamber conditions. Main results showed strong plant growth promotion after inoculation with R. irregularis and both yeast species altered the specific root length of maize. The yeasts also improved maize shoot P content, but only in mycorrhizal plants. More specifically yeasts improved AM hyphal 32 P uptake, but not that of root 33 P uptake. On the other hand, yeasts had no effect on extraradical growth of R. irregularis. Inoculation with yeasts did not result in P isotope dilution measured as specific P isotope activity, indicating that the reported improved P uptake from AM associations in combination with yeasts was most likely not related to P solubilization, whereas alteration in root growth and specific root length seems more likely mechanisms of interactions. We conclude that rhizosphere yeasts promote P nutrition of arbuscular mycorrhizal maize linked to improved specific root length and AM hyphal P uptake. [ABSTRACT FROM AUTHOR]

The article examines the effects of arbuscular mycorrhizal fungi (AMF) on uranium accumulation by barley plants from a field-contaminated soil collected from a closed U mining site in Shangrao County, Jiangxi Province, China. The soil was passed through a two mm sieve, partially sterilized and amended with basal nutrients without phosphorus (P). Further, shoots and roots of barley plants were harvested separately. P concentrations in both shoots and roots of barley plants were markedly influenced by mycorrhizal inoculation and P application. Plant P concentrations increased with increasing P additions, and also increased substantially by mycorrhizal colonization.

Comparisons between plant species or cultivars differing in root hair length have indicated a major impact of root hairs on the mycorrhizal dependency of plants with respect to phosphate (P) uptake. The current study aimed to investigate this relationship by comparing directly the mycorrhizal dependency of a spontaneous root hairless mutant, brb, in Hordeum vulgare cv Pallas and its wild type. Both brb and wild type were grown at different soil P levels in association with different mycorrhizal fungi. P uptake of brb and wild type was similar at high P levels, but P uptake by non-mycorrhizal brb plants at low P levels was substantially lower than that of the non-mycorrhizal wild-type plants. However, P uptake of the mutant was much increased by mycorrhizas and with one fungus, the additional P uptake was effectively translated into increased plant growth. Roots of the mutant contained typical colonization structures and a radioactive tracer confirmed P transport by the extraradical mycelium. This is the first direct evaluation of the relative effectiveness of root hairs and mycorrhizas. Mycorrhizas effectively substituted root hairs in P uptake, whereas the additional P was most often used less effectively in promoting plant growth than P provided by root hairs. [ABSTRACT FROM AUTHOR]

• Some phosphate rocks (PR) contain high concentrations of uranium (U), which are potentially toxic via accumulation in soils and food chains, and plant uptake of U is likely to be influenced by characteristics of roots and associated microorganisms. The relative importance of root hairs and mycorrhiza in U uptake from PR was studied using a root hairless barley (Hordeum vulgare) mutant (Brb) and its wild type (WT).• Both plant genotypes were grown in pots withGlomus intraradicesBEG 87, or in the absence of mycorrhiza, and three P treatments were included: nil P, 2% (w/w) PR and 50 mg KH2PO4-P kg−1 soil.• Mycorrhiza markedly increased d. wts and P contents of Brb amended with nil P or PR, but generally depressed d. wts of WT plants, irrespective of P amendments. Mycorrhiza had contrasting effects on U contents in roots and shoots, in particular in Brb where mycorrhiza increased root U concentrations but decreased U translocation from roots to shoots.• The experiment supports our understanding of arbuscular mycorrhiza as being multifunctional by not only improving the utilization of PR by the host plant but also by contributing to the phytostabilization of uranium.New Phytologist(2004)doi: 10.1111/j.1469-8137.2004.01244.x© New Phytologist(2004) [ABSTRACT FROM AUTHOR]

Abstract Mycorrhizas are ubiquitous symbioses that may have an important role in the movement of C from air to soil. Studies on the effects of climate change factors on mycorrhizas have been concentrated on the effects of atmospheric [CO2 ] whereas temperature effects have been neglected. Based on previous results showing no effect of varying atmospheric [CO2 ] on the development and P uptake of the arbuscular mycorrhizal fungi (AMF) colonizing plants growing in controlled conditions, we hypothesized that soil temperature would have a higher impact on AMF development and nutrient uptake than the effects of [CO2 ] on the host plant. Pea plants were grown in association with either a single isolate of Glomus caledonium or AMF from field soil in factorial combination with the corresponding current (10 °C) or elevated (15 °C) soil temperatures at current (350 p.p.m) or elevated (700 p.p.m) atmospheric [CO2 ]. 33 P uptake by extraradical AMF hyphae was measured independently from root P uptake in a root exclusion compartment. Intraradical colonization developed well at both soil temperatures and almost duplicated from 10 to 15 °C. Extraradical mycelium developed only at 15 °C in the root exclusion compartment and hyphal P uptake could therefore be studied at 15 °C only. Hyphal P uptake differed markedly between inoculum types, but was not altered by growing the host plants at two atmospheric [CO2 ] levels. No significant [CO2 ] × soil temperature interactions were observed. The results suggested that, in the system tested, AMF development and function is likely more influenced by the temperature component of climate change than by its [CO2 ] component. We suggest that much more attention should be paid to temperature effects in future studies. [ABSTRACT FROM AUTHOR]

Summary • We conducted an experiment to test whether phosphorus (P) uptake by mycorrhizal hyphae could be enhanced by growing the host plant under [CO2 ] enrichment and whether any response to [CO2 ] was dependent on C source-sink relationships. • Plant C assimilation, mass allocation, growth and P uptake were measured in pea (Pisum sativum ) plants inoculated with 0, 1 or 5% of a mixture of three Glomus spp. Intra- and extra-radical mycorrhizal development was followed and hyphal 33 P uptake from a root-exclusion compartment was measured. • Total P and 33 P content measurements indicated that root, not hyphal, P uptake was increased by elevated [CO2 ] in the mycorrhizal treatments and that hyphal P uptake was actually reduced by elevated [CO2 ] after 57 d. Neither intra- nor extraradical mycorrhizal development was related to this response. • Plant and fungal measurements suggested positive interactions in plant growth and P uptake only when C source-sink relationships were balanced; high C source (enhanced assimilation at elevated [CO2 ]) and high C sink (increasing mycorrhizal development). The results also indicated that enhanced plant C supply does not alter growth or function of arbuscular mycorrhizal fungi. [ABSTRACT FROM AUTHOR]

The influence of three organic compounds and bakers' dry yeast on growth of external mycelium and phosphorus uptake of the arbuscular mycorrhizal fungus Glomus intraradices Schenck & Smith (BEG 87) was examined. Two experiments were carried out in compartmentalized growth systems with root-free sand or soil compartments. The sand and soil in the root-free compartments were left untreated or uniformly mixed with one of the following substrates (0.5 mg g-1 soil): bakers' dry yeast, bovine serum albumin, starch or cellulose. Effects of the organic substrates on biomass and hyphal length density of the arbuscular mycorrhizal fungus were examined by using specific fatty acid signatures in combination with direct microscopy. Micro-organisms other than the arbuscular mycorrhizal fungus were measured by fatty acid signatures, and radioactive 33P labelling of the root-free soil was used to determine arbuscular mycorrhizal hyphal phosphorus uptake. In general, hyphal growth of G. intraradices was enhanced by yeast and bovine serum albumin, whereas the carbon sources, starch and cellulose, depressed fungal growth. By analysing the fatty acid 16.1w5 from phospholipids (indicating mycelium) and neutral lipids (indicating storage structures) it was shown that increased fungal growth due to yeast was mainly in vegetative hyphae and less in storage structures. Arbuscular mycorrhizal hyphal phosphorus uptake was decreased by cellulose, but unaffected by the other substrates compared with the control. This means that both growth and phosphorus transport by the arbuscular mycorrhizal fungus were decreased under cellulose treatment. However, the composition of the microbial community varied under different substrate conditions indicating a possible interactive component with arbuscular mycorrhizal hyphal growth and phosphorus uptake. [ABSTRACT FROM AUTHOR]

This study was conducted to elucidate the effect of P fertilisation on the function of field communities of arbuscular mycorrhizal fungi (AMF) measured as P transport to flax. Two methods were applied to soil from a long-term field experiment with NaHCO3-extractable soil P levels of 24 and 50 mg kg-1in an experiment under controlled conditions: i) Measurement of plant growth and P uptake in the presence or absence of the fungicide benomyl and ii) measurement of hyphal P transport from a root-free compartment labelled with 32P. Benomyl successfully prevented mycorrhizal function. The absolute contribution of AMF to plant P uptake was of the same magnitude with or without P fertilisation at 27 days after sowing. Therefore, even though plants grown at the higher soil P level had greater P uptake, the relative contribution of AMF to P uptake was greater at the lower P level than at the higher P level (77 and 49%of total P uptake, respectively). The AMF in P-fertilized soil transported less P32 from the root-free compartment to the plant after 23 days than the AMF in unfertilized soil, but this difference disappeared in plants harvested after 27 and 32 days. The production of hyphae was largely similar in both fertilization treatments, indicating that the capacity for P uptake and transport by hyphae of thetwo AMF communities was similar. [ABSTRACT FROM AUTHOR]

Due to uncertainty about the accessibility, amount and quality of the remaining phosphate rock stocks, a replacement of mineral phosphorus (P) fertilizers by sustainable alternatives is desirable. One possibility is to use P rich biochar derived from pyrolysis of organic wastes such as sewage sludge; however, plant P availability is usually reduced in thermally treated products. This study aimed to increase the plant availability of biochar-P by means of phosphate-solubilizing microorganisms (PSM). The solubilization profiles of four Penicillium strains for biochar-P and for calcium, iron and aluminum phosphate were determined in liquid cultures containing each respective P source. The pH, soluble P and organic anion (OA) production were measured in the culture filtrate at the end of the incubation. Subsequently, two efficient Penicillium strains were selected to investigate if the observed in vitro P solubilization could benefit wheat growth in pot experiments. The Penicillium strains differed in their ability to solubilize the four P sources and in their OA production pattern. Addition of individual major OAs to Penicillium- free liquid suspensions showed that especially citrate was closely associated with solubilization of biochar-P. Under semi-sterile soil conditions, the inoculated P. aculeatum established well and this fungus significantly increased both wheat shoot biomass and P content in the biochar-amended treatments. These results open up for new approaches using P-solubilizing Penicillium fungi to increase the fertilizer value of P-rich biochar. [ABSTRACT FROM AUTHOR]

Dried and incinerated sewage sludge (SS) have the potential to be used as phosphorus (P) fertilisers. Arbuscular mycorrhizal fungi (AMF) contribute to plant P uptake; however, their role in P uptake from SS has yet to be fully explored. A compartmented pot system with an isotope pool dilution approach was used to investigate wheat ( Triticum aestivum L.) P uptake from soluble P, dried SS and incinerated SS, via roots and/or AMF hyphae. Wheat was sown into an inner compartment containing a 33 P label with/without AMF ( Rhizophagus irregularis ) inoculum. An outer soil compartment contained the P source. Compartments were separated by mesh of different sizes to allow root and/or AMF hyphal access. Plants obtained P from dried SS via AMF but there was limited evidence that plants obtained P from incinerated SS via AMF. Phosphorus uptake was significantly greater when both roots and hyphae could access dried SS than when only roots could access dried SS. We discuss the results in terms of availability of P to roots and hyphae. We conclude that AMF play an important role in wheat P acquisition from dried SS and therefore can assist in the recycling of P in waste. [ABSTRACT FROM AUTHOR]