Molecular biodiversity of arbuscular mycorrhizal fungi in trace metal-polluted soils

We assessed the indigenous arbuscular mycorrhizal fungi (AMF) community structure from the roots and associated soil of Plantago major (plantain) plants growing on sites polluted with trace metals (TM) and on unpolluted sites. Uncontaminated and TM-contaminated sites containing As, Cd, Cu, Pb, Sn and Zn were selected based on a survey of the TM concentration in soils of community gardens in the City of Montréal. Total genomic DNA was extracted directly from these samples. PCR followed by denaturing gradient gel electrophoresis (PCR-DGGE), augmented by cloning and sequencing, as well as direct sequencing techniques, was all used to investigate AMF community structure. We found a decreased diversity of native AMF (assessed by the number of AMF ribotypes) in soils and plant roots harvested from TM-polluted soils compared with unpolluted soils. We also found that community structure was modified by TM contamination. Various species of Glomus, Scutellospora aurigloba and S. calospora were the most abundant ribotypes detected in unpolluted soil; ribotypes of G. etunicatum, G. irregulare/G. intraradices and G. viscosum were found in both polluted and unpolluted soils, while ribotypes of G. mosseae and Glomus spp. (B9 and B13) were dominant in TM-polluted soils. The predominance of G. mosseae in metal-polluted sites suggests the tolerance of this species to TM stress, as well as its potential use for phytoremediation. These data are relevant for our understanding of how AMF microbial communities respond to natural environments that contain a broad variety of toxic inorganic compounds and will substantially expand our knowledge of AMF ecology and biodiversity.     

Differences in the species composition of arbuscular mycorrhizal fungi in spore, root and soil communities in a grassland ecosystem

Most studies on the species composition of arbuscular mycorrhizal fungi (AMF) have solely analysed mycorrhizal roots or AM spores collected from soil samples. However, the spore production rate and proportions of AMF mycelium in roots and soils have all been shown to vary substantially in a taxon-specific manner. Therefore, in the study presented here we used a molecular approach to analyse the species composition of AMF in spores, intra-radical and extra-radical mycelium in an intensively farmed meadow in central Germany. By polymerase chain reaction and sequencing of the ITS region members of seven different families and species groups within Glomeromycota were identified. The data revealed remarkable differences in the composition of AMF taxa both between the spores and the mycelia, and between the two types of mycelia. Glomus group Ab was dominant in roots and spores, in accordance with previous research. However, members of this group were rarely detected as extra-radical mycelium, in which Paraglomeraceae were dominant, although we found no evidence for the presence of Paraglomeraceae in roots or spores, even when a specific primer set was used. These results may be interpreted as a further indication that AMF are not necessarily obligate symbionts of plants.     

Diverse communities of arbuscular mycorrhizal fungi inhabit sites with very high altitude in Tibet Plateau

Diversity of arbuscular mycorrhizal fungi (AMF) is well studied in many ecosystems, but little is known about AMF in cold-dominated regions with very high altitude. Here, we examined AMF communities associated with two plant species in the Tibet Plateau. Roots and rhizosphere soils of Dracocephalum heterophyllum (pioneer species) and Astragalus polycladus (late-successional species) were sampled at five sites with altitude from 4500 to 4800 m a.s.l. A total of 21 AMF phylotypes were identified from roots and spores following cloning and sequencing of 18S rRNA gene, including eight new phylotypes and one new family-like clade. More AMF phylotypes colonized root samples of D. heterophyllum (5.4±0.49) than of A. polycladus (1.93±0.25). Vegetation coverage was the most important factor influencing AMF community composition in roots. Globally infrequent phylotype Glo-B2 in Glomus group B was the most dominant in roots, followed by globally frequent phylotype Glo-A2 related to Glomus fasciculatum/intraradices group. Our findings suggest that a diverse AMF flora is present in the Tibet Plateau, comprising both potentially habitat-selective and generalist fungi.     

Diversity and structure of AMF communities as affected by tillage in a temperate soil

Arbuscular mycorrhizal fungi (AMF) were studied in differently tilled soils from a long-term field experiment in Switzerland. Diversity and structure of AMF communities were surveyed either directly on spores isolated from the field soil or on spores isolated from trap cultures, planted with different host plants. Single-spore cultures were established from the AMF spores obtained from trap cultures. Identification of the AMF was made by observation of spore morphology and confirmed by sequencing of ITS rDNA. At least 17 recognised AMF species were identified in samples from field and/or trap cultures, belonging to five genera of AMF--Glomus, Gigaspora, Scutellospora, Acaulospora, and Entrophospora. Tillage had a significant influence on the sporulation of some species and non- Glomus AMF tended to be more abundant in the no-tilled soil. The community structure of AMF in the field soil was significantly affected by tillage treatment. However, no significant differences in AMF diversity were detected among different soil tillage treatments. AMF community composition in trap cultures was affected much more by the species of the trap plant than by the original tillage treatment of the field soil. The use of trap cultures for fungal diversity estimation in comparison with direct observation of field samples is discussed.     

The arbuscular mycorrhizal fungus Glomus geosporum in European saline,sodic and gypsum soils

Plants of saline and sodic soils of the Hungarian steppe and of gypsum rock in the German Harz mountains, thus soils of high ionic strength and electric conductivity, were examined for their colonization by arbuscular mycorrhizal fungi (AMF). Roots of several plants of the saline and sodic soils such as Artemisia maritima, Aster tripolium or Plantago maritima are strongly colonized and show typical AMF structures (arbuscules, vesicles) whereas others like the members of the Chenopodiaceae, Salicornia europaea, Suaeda maritima or Camphorosma annua, are not. The vegetation of the gypsum rock is totally different, but several plants are also strongly colonized there. The number of spores in samples from the saline and sodic soils examined is rather variable, but high on average, although with an apparent low species diversity. Spore numbers in the soil adjacent to the roots of plants often, but not always, correlate with the degree of AMF colonization of the plants. As in German salt marshes [Hildebrandt et al. (2001)], the dominant AMF in the Hungarian saline and sodic soils is Glomus geosporum. All these isolates provided nearly identical restriction fragment length polymorphism (RFLP) patterns of the internal transcribed spacer (ITS) region of spore DNA amplified by polymerase chain reaction (PCR). Cloning and sequencing of several PCR products of the ITS regions indicated that ecotypes of the G. geosporum/ Glomus caledonium clade might exist at the different habitats. A phylogenetic dendrogram constructed from the ITS or 5.8S rDNA sequences was nearly identical to the one published for 18S rDNA data (Schwarzott et al. 2001). It is tempting to speculate that specific ecotypes may be particularly adapted to the peculiar saline or sodic conditions in such soils. They could have an enormous potential in conferring salt resistance to plants.     

Cooccurring Gentiana verna and Gentiana acaulis and their neighboring plants in two Swiss upper montane meadows harbor distinct arbuscular mycorrhizal fungal communities

The community composition of arbuscular mycorrhizal fungi (AMF) was analyzed in roots of Gentiana verna, Gentiana acaulis, and accompanying plant species from two species-rich Swiss alpine meadows located in the same area. The aim of the study was to elucidate the impact of host preference or host specificity on the AMF community in the roots. The roots were analyzed by nested PCR, restriction fragment length polymorphism screening, and sequencing of ribosomal DNA small-subunit and internal transcribed spacer regions. The AMF sequences were analyzed phylogenetically and used to define monophyletic sequence types. The AMF community composition was strongly influenced by the host plant species, but compositions did not significantly differ between the two sites. Detailed analyses of the two cooccurring gentian species G. verna and G. acaulis, as well as of neighboring Trifolium spp., revealed that their AMF communities differed significantly. All three host plant taxa harbored AMF communities comprising multiple phylotypes from different fungal lineages. A frequent fungal phylotype from Glomus group B was almost exclusively found in Trifolium spp., suggesting some degree of host preference for this fungus in this habitat. In conclusion, the results indicate that within a relatively small area with similar soil and climatic conditions, the host plant species can have a major influence on the AMF communities within the roots. No evidence was found for a narrowing of the mycosymbiont spectrum in the two green gentians, in contrast to previous findings with their achlorophyllous relatives.     

Thiols of Cu-treated maize plants inoculated with the arbuscular-mycorrhizal fungus Glomus intraradices

Mycorrhizal colonization of roots, fresh weight, content of cysteine, γ-glutamylcysteine (γEC). glutathione (GSH), thiol groups in Cu-binding peptides (CuBP), and the uptake of Cu were measured in roots and shoots of maize ( Zea mays L., cv. Honeycomb F-1) grown in quartz sand, with Cu at 0, 4.5, 9, 15 and 30 μg g⁻¹ added with or without inoculum of the arbuscular-mycorrhizal fungus (AMF) Glomus intraradices . In control plants (no Cu added) AMF significantly reduced shoot growth, but did not affect root growth. At an external Cu supply of 9 μg (g quartz sand)⁻¹ or higher, both mycorrhizal colonization and growth of roots and shoots of mycorrhizal and non-mycorrhizal plants were significantly reduced.
With up to 9 μg Cu g⁻¹, mycorrhizal colonization increased the content of cysteine, γEC and GSH in the roots. However, the amount of thiols in CuBPs was not increased by mycorrhizal colonization in Cu-treated plants and no differences in Cu uptake were detected between non-mycorrhizal and mycorrhizal plants. A CuBP-complex with a relative molecular mass of 7300 and a SH:Cu ratio of 1.77:1 was separated on a Sephadex G-50 column from both non-inoculated and inoculated roots of Cu-treated plants. HPLC chromatography of the CuBPs of both non-inoculated and inoculated roots resulted in a similar peak pattern, indicating that no additional CuBPs were formed by the fungus. In conclusion, our results do not support the idea that AMF protects maize from Cu-toxicity.     

Arbuscular mycorrhizal fungal propagules in a salt marsh

The tolerance of indigenous arbuscular mycorrhizal fungi (AMF) to stressful soil conditions and the relative contribution of spores of these fungi to plant colonization were examined in a Portuguese salt marsh. Glomus geosporum is dominant in this salt marsh. Using tetrazolium as a vital stain, a high proportion of field-collected spores were found to be metabolically active at all sampling dates. Spore germination tests showed that salt marsh spores were not affected by increasing levels of salinity, in contrast to two non-marsh spore isolates, and had a significantly higher ability to germinate under increased levels of salinity (20) than in the absence of or at low salinity (10). Germination of salt marsh spores was not affected by soil water levels above field capacity, in contrast to one of the two non-marsh spore isolates. For the evaluation of infectivity, a bioassay was established with undisturbed soil cores (containing all types of AM fungal propagules) and soil cores containing only spores as AM fungal propagules. Different types of propagules were able to initiate and to expand the root colonization of a native plant species, but spores were slower than mycelium and/or root fragments in colonizing host roots. The AM fungal adaptation shown by this study may explain the maintenance of AMF in salt marshes.     

云南西双版纳野生与栽培绞股蓝根内丛枝菌根真菌的分子多样性

采用巢式-PCR、DNA克隆测序技术,对西双版纳地区野生与栽培绞股蓝根内丛枝菌根真菌(AMF)进行群落结构多样性研究.试验共获得551个含有丛枝菌根真菌18S rDNA 片段的克隆子,经限制性片段长度多态性分析,得到100个RFLP类型,将其划分为20个序列类型,分属于7个科.将20个序列类型的相关序列与GeneBank数据库进行比对,有5个可以鉴定到种,分别为Glomus viscosum、Claroideoglomus etunicatum、Racocetra tropicana、Acaulospora spinosa、Acaulospora mellea.与 MaarjAM数据库中序列进行比对,12个可鉴定为虚拟分类分子种,其中7个未在孢子形态学鉴定方法中获得.西双版纳地区野生与栽培绞股蓝根内丛枝菌根真菌群落组成差异极显著.野生绞股蓝根内Glo₂、Amb₁、Para₁为优势类群,而栽培绞股蓝根内Glo₃、Glo₈、Glo₁₀、Div₁为优势类群.Claroideoglomeraceae和Ambisporaceae仅在野生样本中出现,而Diversisporaceae仅在栽培样品中出现.     

都江堰地区丛枝菌根真菌多样性与生态研究

 调查了都江堰地区3个不同生境样地（般若寺、馒头山、龙池）中85种优势及常见植物的丛枝菌根真菌侵染率,其中78种植物（91.8%）被丛枝菌根真菌侵染。同时对其中58种植物根围土壤中丛枝菌根真菌的多样性进行分析,共分离到5属47种丛枝菌根真菌,其中球囊霉属（Glomus）35种,无梗囊霉属（Acaulospora）7种,原囊霉属（Archaeospora）1种,内养囊霉属（Entrophospora）2种,巨孢囊霉属（Gigaspora）2种。无梗囊霉属和球囊霉属是3个样地共有的优势属。光壁无梗囊霉（Acaulospora laevis）是龙池的优势种,而地表球囊霉（Glomus versiforme）是般若寺和馒头山的优势种。丛枝菌根真菌的孢子密度和种的丰度显著受到海拔相关因子影响,同时丛枝菌根真菌的种类组成也受较大影响。乔木砍伐没有显著影响丛枝菌根真菌的孢子密度和种的丰度,同时对种类组成影响也较小。根围土壤中丛枝菌根真菌的孢子密度与根系侵染率之间没有显著相关性（R2=0.024 8）。     

龙脑香科植物AM真菌的初步研究

对我国云南和海南龙脑香科植物的天然原始林和人工林AM真菌资源进行了调查,对从46处龙脑香林采回的19种龙脑香科树种的根系和根际土壤样品,分别进行显微观察和分离AM真菌的孢子,发现在所调查的19个树种中,所有树种的根系都有不同程度的AM真菌的侵染,高者可达50%,平均为21%,其中在大多数根样中发现有泡囊生成;对土壤样品的分析,分离到大量的孢子,其孢子密度从7~132个/20ml土样不等,平均为58个。对所分离到的孢子进行鉴定,发现无梗囊霉属和球囊霉属的孢子占大多数,其频度和相对多度分别为33.25和46.89;18.04和30.80。研究结果表明,龙脑香科不仅仅能够形成外生菌根,而且也能象大多数热带林木一样能够广泛的形成丛枝菌根。     

Arbuscular fungi and mycorrhizae (Glomales) of the Hel Peninsula,Poland

In the years 1985–1989, the occurrence of arbuscular fungi and mycorrhizae on the Hel Peninsula (Poland) was investigated with the help of 45 soil and root samples collected under 20 plant species of eight families. Except for Zea mays, the other plant species were from uncultivated sites. All soil samples contained spores of arbuscular fungi, of which about 45% were of the genus Glomus. Acaulospora spp. preferred members of the Cupressaceae. Spores of Gigaspora occurred rarely and only in two plant families. Glomus spp. were most frequently associated with plants of the Rosaceae, and species of Scutellospora were found at markedly higher frequencies among roots of plants of the Gramineae and Cupressaceae. A total of 29 spore-forming species and Glomus tenue (a fungus recognizable by its distinctive infections) were found. The most frequently recovered fungus, Glomus tenue, was present in roots of 56.8% of examined plants. Of the spore-forming fungi, the most frequently isolated spores were those of Scutellospora dipurpurascens, then Glomus constrictum, Acaulospora 61, and Glomus microcarpum. The overall spore density in examined samples averaged 99.8 in 100 g dry soil in the range 1 to 547, and was highest in a sample taken from around roots of Festuca arundinacea. The dominant fungi forming spores in sampled soils were Glomus constrictum, Glomus microcarpum, and Scutellospora dipurpurascens. The average species density was 3.9 in 100 g dry soil in the range 1 to 10, and was highest in Corynephorus canescens, Rosa canina, and Thuja occidentalis. Levels of colonization by arbuscular fungi ranged from 0.0 to94.0% (mean 23.3%) of the root length and were highest in Festuca arundinaceae and Zea mays.     

Host preferences of arbuscular mycorrhizal fungi colonizing annual herbaceous plant species in semiarid mediterranean prairies

In this study, we have analyzed and compared the diversities of the arbuscular mycorrhizal fungi (AMF) colonizing the roots of five annual herbaceous species (Hieracium vulgare, Stipa capensis, Anagallis arvensis, Carduus tenuiflorus, and Avena barbata) and a perennial herbaceous species (Brachypodium retusum). Our goal was to determine the differences in the communities of the AMF among these six plant species belonging to different families, using B. retusum as a reference. The AMF small-subunit rRNA genes (SSU) were subjected to nested PCR, cloning, sequencing, and phylogenetic analysis. Thirty-six AMF phylotypes, belonging to Glomus group A, Glomus group B, Diversispora, Paraglomus, and Ambispora, were identified. Five sequence groups identified in this study clustered to known glomalean species or isolates: group Glomus G27 to Glomus intraradices, group Glomus G19 to Glomus iranicum, group Glomus G10 to Glomus mosseae, group Glomus G1 to Glomus lamellosum/etunicatum/luteum, and group Ambispora 1 to Ambispora fennica. The six plant species studied hosted different AMF communities. A certain trend of AMF specificity was observed when grouping plant species by taxonomic families, highlighting the importance of protecting and even promoting the native annual vegetation in order to maintain the biodiversity and productivity of these extreme ecosystems.     

Molecular analysis of arbuscular mycorrhizal fungi colonising a semi-natural grassland along a fertilisation gradient

The community of arbuscular mycorrhizal fungi (AMF) colonizing the roots of Festuca pratensis and Achillea millefolium was characterized in a Swedish pasture at different times, along a gradient of fertilization. The small subunit ribosomal RNA gene was subjected to PCR and denaturing gradient gel electrophoresis (DGGE), sequencing and phylogenetic analysis. The sequences found in this study clustered in 10 discrete sequence groups, seven belonging to Glomus, two to Scutellospora and one to Diversispora. A negative correlation was observed between soil mineral nitrogen and the number of AMF sequence groups in the roots. The frequency of occurrence of AMF in roots decreased dramatically between June and September. No plant-host specificity could be detected.     

蒙古韭共生真菌及其菌根形态学的研究

本文对生长于内蒙古中西部草原和荒漠地区的蒙古韭Alliummongolicum进行了菌根侵染状态的调查研究。发现蒙古韭的根系有丛枝菌根真菌侵染,其菌根类型为疆南星型(Arum-type)。不同地区采集的蒙古韭菌根侵染率不同,由8.76%至36.12%,侵染率与真菌种的丰富度及孢子密度关系不显著。从7个样点的蒙古韭根际土壤中,分离到丛枝菌根真菌26种:无梗囊霉属5种、球囊霉属18种、内养囊霉属和盾巨孢囊霉属各1种,并有1个未知属种。由此可见,球囊霉和无梗囊霉2个属的种出现频度占绝对优势。除了聚生球囊霉Glomusfasciculatum在沙坡头出现最多外,其它样点中Acaulosporasp.1、缩球囊霉G.constrictum、透光球囊霉G.diaphanum和卷曲球囊霉G.convolutum都有较高的出现频度。尽管不同样地蒙古韭根际土壤中丛枝菌根真菌种的丰富度及孢子密度有差异,但样地之间的优势种有相似性。     

内蒙古中部地区马铃薯根际和根系丛枝菌根真菌类群的多样性

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungus,AMF)是菌根真菌中分布最广泛的一类真菌,能够与90%以上的植物形成菌根共生体,并通过调节宿主体内的代谢活动增强植物的抗逆性。【目的】揭示内蒙古马铃薯主产区土壤中AMF的结构与组成,解析马铃薯不同发育阶段以及连作对AMF类群的影响。【方法】以内蒙古中部地区大井村、徐麻夭村和红格尔图村采集的马铃薯根系及根际土为材料,通过PCR扩增建立18S rRNA基因文库,研究不同地点、不同马铃薯生育阶段以及连作对马铃薯根系内和根际土中的AMF类群组成和多样性的影响。【结果】大井村和红格尔图村马铃薯根际土中的AMF的类群多样性优于徐麻夭村,其中Glomus为大井村和红格尔图村马铃薯根际土样本中AMF的优势菌群,而徐麻夭村样本根际土中的优势类群为Diversispora。马铃薯根系中的AMF多样性的研究结果表明,3个供试地点根系内AMF类群的类型没有显著差异,但是AMF类群的比例却不同。大井村根系样本中AMF的优势菌为Diversispora,而Rhizophagus是红格尔图村和徐麻夭村根系样本中的优势AMF类群。同一供...     

Toxicity of diesel fuel to germination,growth and colonization of <Emphasis Type="Italic">Glomus intraradices</Emphasis> in soil and <Emphasis Type="Italic">in vitro</Emphasis> transformed carrot root cultures

Phytoremediation is the use of selected plants to decontaminate polluted environments. Arbuscular mycorrhizal fungi (AMF) may potentially be useful for phytoremediation, but it is not known how petroleum hydrocarbons influence AMF spore germination and hyphal growth. To address this question, germination of spores and germ tube growth of Glomus intraradices Schenck and Smith and Glomus aggregatum Schenck and Smith were assessed in soil contaminated with up to 3% (w/v) of F2 diesel oil or HAGO reference oil. Hyphal growth, colonization and progeny spore production were assessed in vitro using transformed root cultures of Daucus carota and G. intraradices spores in a F2 diesel contaminated medium. In addition, extraradical hyphal growth of G. intraradices colonizing Daucus carota in the presence of F2 diesel was studied. Neither F2 diesel nor HAGO reference oil affected spore germination or germ tube growth in soil. However, in the presence of plant roots, germ tube growth of G. intraradices was reduced and delayed in the presence of F2 diesel and root colonization was not detected. Hyphal growth of pre-colonized carrot roots by G. intraradices was reduced and delayed in F2 contaminated medium compared to controls. F2 diesel did not inhibit spore germination of these AMF species but did reduce colonization, germ tube and hyphal growth. These results suggest that AMF inoculum can be established in petroleum-contaminated sites. However, it may prove beneficial to plant pre-colonized plants to increase the probability of sufficient AMF colonization and growth. The likely mechanism(s) of petroleum toxicity in this plant-microbe system was discussed.     

Evidence of differences between the communities of arbuscular mycorrhizal fungi colonizing galls and roots of Prunus persica infected by the root-knot nematode Meloidogyne incognita

Arbuscular mycorrhizal fungi (AMF) play important roles as plant protection agents, reducing or suppressing nematode colonization. However, it has never been investigated whether the galls produced in roots by nematode infection are colonized by AMF. This study tested whether galls produced by Meloidogyne incognita infection in Prunus persica roots are colonized by AMF. We also determined the changes in AMF composition and biodiversity mediated by infection with this root-knot nematode. DNA from galls and roots of plants infected by M. incognita and from roots of noninfected plants was extracted, amplified, cloned, and sequenced using AMF-specific primers. Phylogenetic analysis using the small-subunit (SSU) ribosomal DNA (rDNA) data set revealed 22 different AMF sequence types (17 Glomus sequence types, 3 Paraglomus sequence types, 1 Scutellospora sequence type, and 1 Acaulospora sequence type). The highest AMF diversity was found in uninfected roots, followed by infected roots and galls. This study indicates that the galls produced in P. persica roots due to infection with M. incognita were colonized extensively by a community of AMF, belonging to the families Paraglomeraceae and Glomeraceae, that was different from the community detected in roots. Although the function of the AMF in the galls is still unknown, we hypothesize that they act as protection agents against opportunistic pathogens.     

Assessment of Natural Mycorrhizal Potential in a Desertified Semiarid Ecosystem

A survey of the natural mycorrhizal potential has been carried out in a representative area of a desertified semiarid ecosystem in the southeast of Spain. Many indigenous plants from the field site were mycorrhizal, including the dominant Anthyllis cytisoides, which had high levels of colonization by arbuscular mycorrhizal fungi (AMF). Low numbers of AMF spores were present in the soil, although a range of species, including Scutellospora calospora, Glomus coronatum, Glomus constrictum, and several Acaulospora species, was represented. Soil infectivities, as determined by a soil dilution method, were similar for most plants tested but were significantly lower for Anthyllis cytisoides. Nevertheless, when a less disruptive method to determine soil infectivity was used, the importance of the mycelial network in maintaining the infectivity of soil under perennial shrubs, such as Anthyllis cytisoides, was highlighted. Seasonal variations in the mycorrhizal infectivity showed that it was higher towards the end of the summer period than in midwinter. In screening trials in a greenhouse, the indigenous AMF did not significantly improve the growth of plants compared with that of noninoculated controls. Augmentation of the soil with an inoculum of Glomus intraradices resulted in improved growth of Anthyllis cytisoides in both sterile and nonsterile conditions, in contrast to results obtained following inoculation with Glomus mosseae or another Glomus sp. Our findings suggest that the indigenous inoculum levels of AMF are inadequate to support an extensive revegetation program in the absence of an additional mycorrhizal inoculum.     

Occurrence of arbuscular mycorrhizal fungi in saline soils of the Tabriz Plain of Iran in relation to some physical and chemical properties of soil

The abundance and distribution of arbuscular mycorrhizal fungi (AMF) were evaluated in the Tabriz Plain, where soil salinity levels range from 7.3 to 92.0 dS/m. Soil and root samples were collected from the rhizosphere of several glycophytes (Allium cepa L., Medicago sativa L., Triticum aestivum L. and Hordeum vulgare L.) and halophytes (Salicornia sp. and Salsola sp.) and were analysed for spore number in soil, root colonization with AMF and some physical and chemical soil properties. The number of AMF spores was not correlated significantly with soil salinity but suffered adverse effects from the accumulation of some anions and cations. Cluster analysis of correlation matrices showed that root colonization, soil pH, sand and clay percent, and soil-available P, rather than soil salinity and ion concentrations, were closely related with spore number. The percentage of root length colonized in glycophytes significantly decreased with increasing soil salinity. Barley roots showed 5% mycorrhizal colonization in high soil salinity (~20 dS/m). Halophyte roots were not mycorrhizal but more spores were found in rhizosphere than in non-rhizosphere soil.