Effects of arbuscular mycorrhizal inoculation on cadmium accumulation by different tobacco (Nicotiana tabacum L.) types

The effect of arbuscular mycorrhiza (AM) on cadmium (Cd) uptake by tobacco (Nicotiana tabacum L.) was studied in a pot experiment. Three commercial varieties, Basma BEK, K326 and TN90, representing three distinct tobacco types, were each grown in a different soil with nutritional conditions matching as closely as possible their requirements for field production. Cd concentrations in these soils were within the background range. Each variety was either non-mycorrhizal or inoculated with one of five AM fungal isolates. Cd concentration in leaves was decreased by inoculation with selected isolates in the K326 and TN90 variety grown in acidic soils. In contrast, it was increased by inoculation with most isolates in the Basma BEK variety grown in a basic soil with low Cd availability. Besides, plants of all three varieties had significantly higher leaf concentrations of phosphorus and nitrogen in some inoculated treatments. The percentage of root colonisation was mostly low in the inoculated treatments. In the Basma BEK and TN90 variety, the tested AM fungal isolates differed in their ability to colonise roots, but no correlation was found between the root colonisation of an isolate and its effects on the Cd concentrations in tobacco leaves. One isolate influenced most pronouncedly Cd concentrations and improved mineral nutrition in all the three combinations of variety and soil despite its low colonisation levels. AM symbiosis probably affected Cd uptake of tobacco by indirect mechanisms such as stimulation of root growth or mycorrhizal plant mediated changes in chemical or biological soil properties.     

Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant

This study was performed to evaluate the ability of white-rot fungi to decolorize dye effluents. A total of 222 isolates of white-rot fungi were initially investigated to assess their ability to decolorize chemically different synthetic dyes in solid medium, resulting in selection of 25 isolates including four isolates of Berkandera adusta, five isolates of Ceriporia lacerata, three isolates of Irpex lacteus, one isolate of Perenniporia fraxinea, ten isolates of Phanerochaete spp., one isolate of Phlebia radiata, and one isolate of Porostereum spadiceum. Of the 25 isolates, B. adusta KUC9065, C. lacerata KUC8090, P. calotricha KUC8003, and P. spadiceum KUC8602 were finally selected on the basis of their ability to decolorize synthetic dyes in liquid medium, and were used to decolorize industrial effluents. B. adusta KUC9065 increased the transmittance of visible light by 71–92 %. Decolorization of wastewater by B. adusta KUC9065 was probably caused by the lignin-modifying enzymes produced by the fungus. In addition, the acute toxicity to Daphnia magna decreased from 2.5 to 2.1 and from 3.5 to 2.6 toxic units over 24 and 48 h, respectively.     

Comparaison des aptitudes parasitaires de clones de Trichoderma vis-a-vis de quelques champignons a sclerotes

Nineteen monoconidial isolates (referred to as clones) of Trichoderma from different species aggregates, one isolate of Gliocladium virens, and one isolate of an Acrostalagmus sp. (that was naturally associated with sclerotia of Sclerotinia spp and Macrophomina phaseolina) were tested. They were incubated in controlled conditions, in sterile soil, with sclerotia of Corticium rolfsii, Sclerotinia minor, or S. sclerotiorum. At the end of appropriate periods of incubation (respectively 26, 20 and 8 days), the sclerotia were retrieved from soil and checked for invasion by the antagonist. Important differences between the parasitic ability of Trichoderma clones were noted. Clones from at least three different species (T. aureoviride, T. hamatum, T. harzianum) exhibited a high antagonistic activity. Activity of the G. virens isolate was at the same level as the best clones of Trichoderma, whereas no parasitic tendencies were found in the isolate of Acrostalagmus sp., thus confirming previous results.A rather good correlation was found between the capacity of the clones for attacking C. rolfsii sclerotia and their ability to parasitize both Sclerotinia.In conclusion, it is proposed that a screening with only one of the sclerotial species would give clones efficient against all three, and possibly against related sclerotial types.     

Iron mobilization by heathland plant extracts

Aqueous extracts of leaves and shoots of Calluna vulgaris, Erica tetralix, and Betula pendula were reacted with iron compounds in the laboratory. Extracts of B. pendula were found to be most active in solubilizing iron. The iron mobilizing capacity of extracts of C. vulgaris depended upon plant age, season, and soil conditions. C. vulgaris shoots were found to be more readily leached of their soluble organic matter than those of B. pendula but yielded little soluble inorganic material. C. vulgaris extracts were the most acid (pH 4.2–4.5) of those examined.     

Biosynthetic potential of actinomycetes in brown forest soil on the eastern coast of the aegean sea

The taxonomic and functional structures of the actinomycetal complex in the litter and upper horizon of the brown forest soil was studied in a Pinus brutia var. pendulifolia forest on the eastern coast of the Aegean Sea. The complex of actinomycetes included representatives of the Streptomyces and Micromonospora genera and oligosporus forms. Streptomycetes predominated (73.8%) in the soil, and micromonospores (66.7%) were dominants in the litter. Thirty isolates of ten Streptomyces species from five series and three sections prevailed. In the upper soil horizon, species of the Helvolo-Flavus Helvolus section predominated (48%); the S. felleus species occurred most frequently. Among the isolated cultures, the S. globisporus and S. sindenensis species capable to produce antitumor antibiotics were found. The testing of the antimicrobial activity of the natural isolates showed that five strains inhibit the growth of pathogenic Fusarium sp., Alternaria sp., Acremonium sp., and Bipolaris sorokiniana fungi. When testing the effect of streptomycetes on the production of cellulases, a high-efficient strain belonging to the S. noboritoensis species was revealed. All the streptomycetes isolated from the brown forest soil produced auxins at the rate of 7.8 to 19.7 μg of indole acetic acid/mL of the liquid medium in the presence of 200 mg/L of tryptophan. Twelve isolates of streptomycetes were transferred to the collection of biotechnologically promising cultures for studying their properties.     

Hyperparasitism of oospores of Phytophthora megasperma var. sojae

Hyperparasites of oospores of Phytophthora megasperma Drechs. var. sojae Hildb. were present in each of 15 field soils tested. Maximum numbers of oospores parasitized ranged from 42.5 to 87.5% for flooded soils, and from 25.5 to 73.0% for soils adjusted to 50% water holding capacity; the mean for all soils was 51.5%. The frequency of hyperparasitism was not correlated with the disease potential soils for Phytophthora root-rot of soybean as determined in seedling tests on flooded soil samples. Of eight isolated hyperparasitic fungi tested in steamed soil, the most efficient parasites were Hyphochytrium catenoides, Humicola fuscoatra, and Pythium monospermum, each of which parasitized at least 76% of oospores during 3 weeks. Hyphae were not parasitized by any of the eight fungi. Parasitism by H. catenoides in sterilized soil increased as soil temperature increased from 16° to 28°C. Parasitism by P. monospermum was maximum at 20°–24°C. Oospores of P. meyasperma var. sojae race 7 were more resistant to infection by hyperparasites than were oospores of races 1 and 3. Oospores produced in culture were slightly more susceptible to hyperparasitism in soils than were oospores produced in soybean seedlings.     

Root-nodule bacteria from indigenous legumes in the north-west of Western Australia and their interaction with exotic legumes

Bacteria were isolated from root-nodules collected from indigenous legumes at 38 separate locations in the Gascoyne and Pilbara regions of Western Australia. Authentication of cultures resulted in 31 being ascribed status as root-nodule bacteria based upon their nodulation of at least one of eight indigenous legume species. The authenticated isolates originated from eight legume genera from 19 sites. Isolates were characterised on the basis of their growth and physiology; 20 isolates were fast-growing and 11 were slow-growing (visible growth within 3 and 7 d, respectively). Fast-growers were isolated from Acacia, Isotropis, Lotus and Swainsona, whilst slow-growers were from Muelleranthus, Rhynchosia and Tephrosia. Indigofera produced one fast-growing isolate and seven slow-growing isolates. Three indigenous legumes (Swainsona formosa, Swainsona maccullochiana and Swainsona pterostylis) nodulated with fast-growing isolates and four species (Acacia saligna, Indigofera brevidens, Kennedia coccinea and Kennedia prorepens) nodulated with both fast- and slow-growing isolates. Swainsona kingii did not form nodules with any isolates. Fast-growing isolates were predominantly acid-sensitive, alkaline- and salt-tolerant. All slow-growing isolates grew well at pH 9.0 whilst more than half grew at pH 5.0, but all were salt-sensitive. All isolates were able to grow at 37 °C. The fast-growing isolates utilised disaccharides, whereas the slow-growing isolates did not. Symbiotic interactions of the isolates were assessed on three annual, one biennial and nine perennial exotic legume species that have agricultural use, or potential use, in southern Australia. Argyrolobium uniflorum, Chamaecytisus proliferus, Macroptilium atropurpureum, Ononis natrix, Phaseolus vulgaris and Sutherlandia microphylla nodulated with one or more of the authenticated isolates. Hedysarum coronarium, Medicago sativa, Ornithopus sativus, Ornithopus compressus, Trifolium burchellianum, Trifolium polymorphum and Trifolium uniflorum did not form nodules. Investigation of the 31 authenticated isolates by polymerase chain reaction with three primers resulted in the RPO1 primer distinguishing 20 separate banding patterns, while ERIC and PucFor primers distinguished 26 separate banding patterns. Sequencing the 16S rRNA gene for four fast- and two slow-growing isolates produced the following phylogenetic associations; WSM1701 and WSM1715 (isolated from Lotus cruentus and S. pterostylis, respectively) displayed 99% homology with Sinorhizobium meliloti, WSM1707 and WSM1721 (isolated from Sinorhizobium leeana and Indigofera sp., respectively) displayed 99% homology with Sinorhizobium terangae, WSM1704 (isolated from Tephrosia gardneri) shared 99% sequence homology with Bradyrhizobium elkanii, and WSM1743 (isolated from Indigofera sp.) displayed 99% homology with Bradyrhizobium japonicum.     

Biologically-induced hydrolysis of parathion in soil: Isolation of hydrolyzing bacteria

Fifty bacterial isolates from a parathion-treated soil (Gilat, Israel) were tested for their ability to hydrolyze the organophosphorus insecticide, parathion in peptone-yeast extract medium. After 5 days 33 isolates had hydrolyzed at least a portion of the added parathion. Eight of these isolates hydrolyzed 75% of the added parathion in 5 days and appeared to be Bacillus strains. Ten of these 33 isolates had hydrolyzed all of the parathion after 5 days and appeared to be Arthrohacter strains. One isolate from each group was tested further. During the logarithmic phase of growth, Bacillus sp., isolate 10, hydrolyzed less than 10% of the parathion added to peptone-yeast extract medium and was not active in parathion hydrolysis when inoculated into sterilized, parathion-treated soil. Arthrobacter sp., isolate 6, hydrolyzed parathion rapidly in peptone-yeast extract medium and in sterilized, parathion-treated soil. It used parathion or its hydrolysis product, p-nitrophenol, as sole carbon source. The parathion hydrolyzing enzyme appeared to be constitutive in isolate 6. Single applications of p-nitrophenol at concentrations greater than 1 mM inhibited growth but successive additions of smaller amounts permitted growth to continue.     

A PCR-DGGE method for detecting arbuscular mycorrhizal fungi in cultivated soils

Arbuscular mycorrhizal (AM) fungi (AMF) are important components of agro-ecosystems and are especially significant for productive low-input agriculture. Molecular techniques are used to investigate fungal community composition in uncultivated, disturbed, or contaminated soils, but this approach to community analysis of AMF in agricultural soils has not been reported. In this study, a polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) procedure for the detection of fungal 18S ribosomal RNA gene was developed with reference cultures of seven isolates (representing five AMF species). These reference cultures were chosen because isolates of their species were putatively identified in a previous survey of farm field soils in the province of Saskatchewan, Canada. A reference PCR-DGGE profile was generated using DNA extracted and amplified from the spores of these cultures. The effectiveness of the procedure was tested by its application to soil samples from 38 farms. Prominent bands from the PCR-DGGE profiles of these samples were excised for sequence analysis. The total number of species recovered was low in comparison to other AMF community surveys of temperate climate locations. The majority of the sequences recovered were Glomus species. Scutellospora calospora, a previously undetected AM fungus in Saskatchewan was found. Though not without its drawbacks, this approach to community composition analysis of AMF was faster than conventional trap cultivation methods.     

Microbial degradation of several acetamide,acylanilide, carbamate,toluidine and urea pesticides

Soil enrichment was used to isolate soil microorganisms capable of degrading isopropyl carbanilate (propham), 3′,4′-dichloropropionanilide (propanil), 3′-chloro-2-methyl-p-valerotoluidide (solan), and methyl 3,4-dichlorocarbanilate (swep) in a muck and a silty clay loam. Degradation of the pesticides in enrichment solutions, and by pure cultures of effective microbial isolates was demonstrated by the production of the corresponding aniline, chloride ion liberation and disappearance of the parent compound. Degradation products were identified by gas-liquid and thin-layer chromatography.Organisms isolated include Pseudomonas striata Chester, Achromobacter sp., Aspergillus ustus (Bain) Thorn and Church, A. versicolor (Vuill. Tirabaschi), Fusarium oxysporum Schlecht, F. solani (Martius) Appel and Wollenweber, Penicillium chrysogenum Thorn, P. janthinellum Biourge, P. rugulosum Thorn and Trichoderma viride Pers. Each organism demonstrated a unique substrate specificity and was capable of degrading other aniline-based pesticides of the acetamide, acylanilide, carbamate, toluidine and urea classes.     

Diversity and phylogeny of rhizobial strains isolated from Lotus uliginosus grown in Uruguayan soils

Lotus uliginosus is generally nodulated by rhizobia of the genus Bradyrhizobium when used for improvement of Uruguayan pastures. The genetic diversity and phylogenetic relationships of 111 isolates from nodules of L. uliginosus collected from four fields with or without prior inoculation history were analyzed in this study. Genetic diversity estimated by ERIC-PCR revealed 75 different genomic fingerprints, and showed a relatively greater value compared with other methods and varied by soil type. 16S ribosomal RNA gene RFLP analysis revealed three different ribogroups, A, B and C, with 71 isolates in ribogroup A, three isolates in ribogroup B and only one in ribogroup C. Phylogenetic analyses based on 16S RNA gene sequences, ITS, as well as atpD, recA and glnII gene sequences indicated that ribogroup A strains were affiliated with B. japonicum bv. genistearum strains. The three isolates in ribogroup B did not clearly associate with any Bradyrhizobium species described previously and could represent a novel species within this genus. Unlike B. japonicum strains these isolates were able to nodulate and fix nitrogen with other Lotus species as well as with Spartium, a leguminous shrub. The unique isolate in ribogroup C clustered with Mesorhizobium and appeared genetically and phenotypically related to broad host-range Mesorhizobium sp. NZP2037. Our data suggest that Uruguayan soils contain native or naturalized bradyrhizobia that are able to nodulate L. uliginosus as efficiently as the commercial strain NZP2309 but could have adaptive advantages making them more suitable for inoculant purposes.     

Concomitant biocontrol of pepper Phytophthora blight by soil indigenous arbuscular mycorrhizal fungi via upfront film-mulching with reductive fertilizer and tobacco waste

Purpose

Both reductive disinfestation and germicide can suppress Phytophthora blight, while soil arbuscular mycorrhizal (AM) fungi also have biocontrol effects on soilborne diseases. However, the combined effects of reductive disinfestation and botanical germicide [e.g., tobacco (Nicotiana tabacum L.) waste] on pepper (Capsicum annuum L.) Phytophthora blight and soil AM fungi are at present unclear. The purposes of this work were to develop application strategy for dealing with pepper Phytophthora blight, and to explore the concomitant contribution from soil indigenous AM fungi.

Materials and methods

A field experiment with four treatments was carried out in a pepper continuous planting field, including normal film-mulching with common fertilizer (control), normal film-mulching with reductive fertilizer (RF), upfront film-mulching with reductive fertilizer (UM+RF), and upfront film-mulching with reductive fertilizer and tobacco waste (UM+RF+TW). Phytophthora blight severity index, root mycorrhizal colonization rate, and the biomass and nutrient (N, P, and K) concentrations of shoots, roots, and fruits of pepper were measured. Soil pH, organic C, mineral N, available P, available K, acid phosphatase activity, and AM fungal abundance were also tested. The Pearson correlation analysis was carried out among plant and soil parameters.

Results and discussion

RF tended to increase pepper fruit yield compared with control, and UM+RF tended to decrease Phytophthora blight severity in relative to RF, while UM+RF+TW tended to decrease blight severity and increase fruit yield compared with UM+RF, and had a significantly (P?<?0.05) lower blight severity and a significantly higher fruit yield in comparison with control. UM+RF+TW also significantly decreased soil pH, and significantly increased AM fungal population and colonization, as well as soil acid phosphatase activity and available P concentration. In addition, UM+RF+TW had a significantly higher fruit K accumulation ratio, which negatively correlated with blight severity and positively correlated with fruit yield. However, fruit K accumulation ratio positively correlated with fruit P accumulation ratio, which was greatly elevated by the enhanced mycorrhizal colonization.

Conclusions

The coalition of reductive disinfestation (upfront film-mulching with reductive fertilizer) and tobacco waste had the greatest suppression of pepper Phytophthora blight, and the highest fruit yield and AM fungal population. It suggests that combined application of reductive disinfestation and botanical germicide has superposition in inhibiting Phytophthora blight and increasing fruit yield, and there seems to be a concomitant biocontrol by soil indigenous AM fungi which could enhance P and K transfer from plant to fruit.

     

The uptake and translocation of phosphate by mycelial strands of pine mycorrhizas

Uptake and rapid translocation of ³²P-orthophosphate to Pinus radiata mycorrhizas from soil by mycelial strands of Rhizopogon luteolus was demonstrated. In greenhouse material, translocation occurred from soil for at least 12 mm and some 30–80 per cent of phosphate absorbed from 5 × 10^?6M as KH₂PO₄ was translocated. In the field, translocation occurred for 12 cm. Uptake by excised mycelial strands was metabolically mediated. Translocation occurred more rapidly when the untreated ends of strands were placed in an osmoticum: polarity in translocation was also observed. It was concluded that uptake and translocation by mycelial strands (as distinct from individual hyphae) provide an effective method for mycorrhizal exploitation of large inter-root soil volumes and assist the plants in competition for nutrients.Large differences occurred between strains of the same species in mycelial strand growth in soil. Mycelial strands of R. luteolus grew through the test soil at 1.3-2.9 mm/day and along P. radiata roots at 1.7 mm/day at 25°C day and 16°C night temperatures.     

The leaves of Pelargonium sidoides may substitute for its roots in the treatment of bacterial infections

Pelargonium sidoides (Geraniaceae) is a medicinal plant used for the treatment of various infections including tuberculosis and bronchitis. Traditionally, only the roots of the plant are used for medicinal formulations in the Eastern Cape. In addition to traditional uses, there is a great demand for the plant for export, therefore, the rate of its harvesting and the number of its collector has increased in recent years. This has led to a drastic drop in the population of the species in the wild. A method that could achieve the sustainable harvesting of P. sidoides would be to substitute its shoot for the roots in medicinal formulations. A comparative study of the antibacterial activities of the leaves and the roots of the plant was conducted on the materials collected from three different populations. Generally, both the shoot and the roots of P. sidoides have antimicrobial properties. There was no significant observable difference between the MIC of extracts from both parts. The choice of the root by the traditional healers over the leaves may be arbitrary or due to easy collection. The leaves of P. sidoides may, as well, substitute for its roots in medicinal formulations especially in the treatment of bacterial diseases like tuberculosis and bronchitis.     

Arbuscular mycorrhizal fungal spore-associated bacteria affect mycorrhizal colonization,plant growth and potato pathogens

Arbuscular mycorrhizal (AM) fungi and their bacterial associates are essential living components of the soil microbiota. From a total of 385 bacteria previously isolated from spores of AM fungi (AMB), 10 were selected based on ability to inhibit growth of plant pathogens. Effects of these isolates on AM fungal colonization, plant growth in potato (Solanum tuberosum L.) and inhibition of pathogens was investigated. AM fungal root colonization of potato was 7-fold higher in the presence of the Pseudomonas FWC70 isolate in a greenhouse and was 6–9-fold higher in the presence of the three isolates Pseudomonas FWC70, Stenotrophomonas FWC94 and Arthrobacter FWC110 in an outdoor pot experiment. Several growth traits of potato were stimulated by the Pseudomonas isolates FWC16, FWC30 and FWC70 and by the Stenotrophomonas isolate FWC14. All three Pseudomonas isolates showed inhibition against Erwinia carotovora, Phytophthora infestans and Verticillium dahliae but Stenotrophomonas isolates were variable. Protease(s), siderophores and indole acetic acid were produced by all isolates. Chitinase(s) were produced by all Stenotrophomonas and phosphate-solubilizing activity by all Pseudomonas isolates, the Stenotrophomonas FWC14 isolate and the Arthrobacter FWC110 isolate. We conclude that some AMB are multifunctional and production of extracellular enzymes and bioactive compounds are likely mechanisms for their multifunctional activities. Our results show that some AMB are likely to contribute to the often described ability of AM fungi to inhibit pathogens, acquire mineral nutrients and modify plant root growth.     

Resistance in natural populations of three wild Lactuca species from Israel to highly virulent Californian isolates of Bremia lactucae

Seedlings of 213 accessions representing 9, 14, and 10 Israeli natural populations of the wild Lactuca serriola, L. saligna, and L. aculeata, respectively, were initially screened for their resistance to a pathotype CAVIII isolate of Bremia lactucae. All 60 L. serriola accessions were susceptible while all 83 accessions of L. saligna were resistant. Out of the 69 L. aculeata accessions, 36 (52.2 %) were resistant. From those resistant accessions, 56 L. saligna and 23 L. aculeata accessions were then tested at the seedling stage for their reaction against five highly virulent isolates originating from California and representing the two current major pathotypes and a novel type of B. lactucae; true leaves of adult plants were also tested with two out of these five isolates. Our study supports previous observations that L. saligna is highly resistant to B. lactucae. However, our results provide additional evidence that L. saligna may not be an absolutely non-host plant for B. lactucae at least at a seedling stage, which is in agreement with other recent data for this species. Sixteen (69.6 %) out of the 23 L. aculeata accessions expressed resistance against all isolates tested, even in seedling stage as well as in true leaves of adult plants. This study is probably the first report of detailed screening of resistance to some B. lactucae isolates in natural populations of L. aculeata. These patterns of resistance reactions show that L. aculeata, a species within the primary lettuce gene pool, should be considered as an attractive source of germplasm for resistance breeding of cultivated lettuce (L. sativa).     

Continuous culture of mixed sediment bacteria in the presence of mercury

Continuous culture methods were used to isolate bacteria from sediment from Lake Ontario. These mixed cultures were grown in chemostats at different dilution rates and the glucose concentration in the culture vessel, the optical density, the biomass of cells, and the number and types of bacteria present were monitored for at least 80 generations. Two bacterial types, bothPseudomonas spp., were present at all dilution rates in significant quantities. The mixed cultures exhibited a reciprocal relationship between dilution rate and biomass (and number of bacteria). When Hg was added to the growth medium at a concentration of 5 mg 1^?1, the bacteria tolerated that concentration at a dilution rate of 0.117 h^?1 substantial changes in the population were noted at a concentration of 10 mg 1^?1 Hg. One of the isolates from the mixed culture would not grow at 5 or 10 mg 1^?1 of Hg in continuous culture at a dilution rate of 0.066 h^?1. In the mixed continuous culture the same isolate showed only minimal response to a Hg concentration of 10 mg 1^?1.     

Isolation and identification of oxamyl-degrading bacteria from UK agricultural soils

Bacteria capable of utilising oxamyl as the sole carbon source were isolated from seven different agricultural soils that had previously demonstrated enhanced oxamyl degradation in a soil incubation study. Partial sequencing and alignment of the 16S rRNA gene showed little diversity amongst isolates, with 26 of the 27 isolates demonstrating similarity to the genus Aminobacter. The most common species isolated was Aminobacter aminovorans, while a number of the isolates demonstrated an equal degree of similarity to the species Aminobacter niigataensis and Chelatobacter heintzii. One isolate was identified as Mesorhizobium sp. This is the first time that organisms involved in the degradation of oxamyl have been isolated and identified.     

Forms of phosphorus in bacteria and fungi isolated from two Australian soils

To understand the origin of organic and condensed forms of phosphorus (P) in soils, detailed information about P forms in microorganisms is required. We isolated 7 bacteria and 8 fungi from two Australian soils and analyzed the P forms in their pure cultures by extraction with NaOH-EDTA followed by ³¹P solution nuclear magnetic (NMR) spectroscopy. The bacteria belonged to the actinobacteria and the fungi to the ascomycota, as determined by rDNA sequencing. The proportions of broad forms of P were significantly different between the bacterial and fungal isolates (analysis of similarities, p = 0.001). Ortho-, pyro- and polyphosphate were present in higher proportions in fungi, while monoester and diester P were present in higher proportions in bacteria. Spectral deconvolution of the monoester region revealed 15 distinct resonances. The three major ones, which were identified by spiking experiments as glycerol 1-phosphate, glycerol 2-phosphate and adenosine-5′-monophosphate (AMP), comprised 56–74% of P in the monoester region. Ordination by principal component analysis and testing for treatment effects using analysis of similarities showed significant separation of P distribution in the monoester region between bacterial and fungal isolates (p = 0.007). However, neither group of microorganisms had a specific single P form which might be considered characteristic. As such, it may be difficult to distinguish soil P from bacterial or fungal origins, with the possible exception of a predominantly fungal origin of pyro- and polyphosphate. The identification of three major resonances in the monoester region of microorganisms is important, since the same resonances are found in ³¹P NMR spectra of soil extracts.