Arbuscular mycorrhizal fungi

In this study, we examined the use of the 15N natural abundance method to quantify the percentage N derived from fixation of atmospheric N2 in honeybush (Cyclopia spp.) shrubs and trees in the fynbos, South Africa. Non-fixing shrubs and trees of similar phenology to the Cyclopia species were chosen as reference plants. These reference plants were selected to cover a range of mycorrhizal associations (ericoid mycorrhizal, arbuscular mycorrhizal and non-mycorrhizal). Isotopic analysis revealed a wide range of foliar δ15N values for the reference plants, including many very negative values. The marked differences in δ15N values were defined by the mycorrhizal status of the reference plant species, with the ericoid and arbuscular mycorrhizal plants showing lower foliar δ15N values relative to their non-mycorrhizal counterparts. In contrast, the δ15N values of the N2-fixing Cyclopia species were uniformly clustered around zero, from −0.11‰ to −1.43‰. These findings are consistent with the observation that mycorrhizal fungi discriminate against the heavier 15N isotope during transfer of N from the fungus to the host plant, leaving the latter depleted in 15N (i.e. with a more negative δ15N value). However, a major assumption of the 15N natural abundance method for estimating N2 fixation is that both legume and reference plant should have the same level of fractionation associated with N uptake. But, because mycorrhizal associations may strongly affect the level of fractionation during N uptake and transfer, the test legume should belong to the same mycorrhizal group as the chosen reference plant species. As shown in this study, if the mycorrhizal status of the legume and the reference plant differs, or cannot be assessed, then the 15N natural abundance technique cannot be used to quantitatively estimate N2 fixation.

We studied seasonal variation in population attributes of arbuscular mycorrhizal (AM) fungi over 2 years in four sites of temperate grasslands of the Argentinean Flooding Pampas. The sites represent a wide range of soil conditions, hydrologic gradients, and floristic composition. Lotus glaber, a perennial herbaceous legume naturalised in the Flooding Pampas, was dominant at the four plant community sites. Its roots were highly colonised by AM fungi. Temporal variations in spore density, spore type, AM root colonisation, floristic composition and soil chemical characteristics occurred in each site and were different among sites. The duration of flooding had no effect on spore density but depressed AM root colonisation. Eleven different types of spores were recognized and four were identified. Two species dominated at the four sites: Glomus fasciculatum and Glomus intraradices. Spore density was highest in summer (dry season) and lowest in winter (wet season) with intermediate values in autumn and spring. Colonisation of L. glaber roots was highest in summer or spring and lowest in winter or autumn. The relative density of G. fasciculatum and G. intraradices versus Glomus sp. and Acaulospora sp. had distinctive seasonal peaks. These seasonal peaks occurred at all four sites, suggesting differences among AM fungus species with respect to the seasonality of sporulation. Spore density and AM root colonisation when measured at any one time were poorly related to each other. However, spore density was significantly correlated with root colonisation 3 months before, suggesting that high colonisation in one season precedes high sporulation in the next season.

Fungi share an ancient historical bond with humans which is completely fascinating.
The Strange History of Life
Humans have always been fascinated with life in all its forms, but thousands of years ago, we only classified life on Earth into two categories – plants and animals. We can thank Aristotle for that, and he further divided animals into those with and without blood, as well as those in the land, sea, and air. That rudimentary system remained in place until the 1600s. In the 18th century, Carolus Linnaeus divided life into the kingdoms of animals and plants, and then further began dividing those into different genera and species, which is why we have the two-part naming system in science (Homo sapiens, for example; Homo is the genus and sapiens is the species.

It wasn’t until the middle of the 19th century that single-celled organisms were finally given their due as a separate kingdom of life (Protista). Seventy years later, single-celled organisms were divided into eukaryotes and prokaryotes, so bacteria became the 4th kingdom of life. Although fungi had been recognized as a unique part of the animal kingdom, it was not separated into its own kingdom until 1969. This five-kingdom system remains the most widely accepted format for classifying life on Earth.
All classifications of life until recently, including the expansion from two kingdoms to five, were based on physical observations of how things looked, even under a microscope. This is how the closeness and relationships between species, genera, classes, orders and kingdoms were decided. Given that fact, it comes as no surprise that most people classified fungi as plants for so long. The similarity in appearance is pretty clear, like little red and white trees…

However, thanks to modern technology, the analysis of genetic relationships between species and organisms is now possible, and it shows something very interesting. By examining the genes of different species, both animal and fungi, the mutational changes can be observed, and genealogical relationships can be determined that go back millions of years.

As it turns out, animals and fungi share a common ancestor and branched away from plants at some point about 1.1 billion years ago. It was only later that animals and fungi separated on the genealogical tree of life, making mushrooms more closely related to humans than plants. Most likely, this common ancestor was a single-celled organism that had sperm-like characteristics (like an animal) and then a later developmental stage with a stronger cell wall (fungi).

Are mushrooms vegetables?
Simple answer? No, it’s not a vegetable. Mushrooms are fruiting bodies of macroscopic filamentous fungi. Earlier when mycology (the study of fungi) arose, it was a part of botany. This happened as fungi were considered to be primitive plants. The major difference between a plant (vegetable) and mushroom is how they acquire their food. In the case of plants, they possess chlorophyll and make their food via photosynthesis. Fungi, on the other hand, exist on decaying material in nature. Also the obvious structural differences, such as lack of leaves, roots, and seeds.So fungi now have their own kingdom on the basis of cellular organization.

However, this is the science side of things. Now let us take a look at the other side, the side of food! In terms of food and nutrition, mushrooms are often put in the category of vegetables. The reason for this lies in the nutritional value. Mushrooms and plants have similar nutritional attributes. The nutrients provided by mushroom are spread across various core food groups such as meat and grains. All this has made mushroom a valuable asset in the kitchen both for taste and nutrition.

The Connection Between Mushrooms and Men
Haven’t you ever noticed that eating a perfectly cooked portobello mushroom is closer to eating meat than a salad? Well, that isn’t exactly a scientific explanation of the connection, but this new revelation of our link to fungi does shed some light on the trouble we have with fungal infections in the body. It is notoriously difficult to treat fungal infections, rather than viral and bacterial pathogens, and this close genetic link may explain why.

Fungi and animals are both eukaryotes, with nuclei and other complex structures inside their cell membranes, whereas bacteria are much simpler – composed of just genetic material and a cell wall. Therefore, when we try to fight a bacterial infection, the body is able to easily differentiate and neutralize the threat. Unfortunately, with fungal infections, the body sometimes thinks that the infection is…. us. Drugs that are synthesized to fight the cells of fungal infections may also attack healthy human cells, as there is very little structural difference.

The aims of this studies were: (i) to examine the influence of heavy metal content (Zn, Cd, Pb, Fe, Cu) and other physico-chemical soil parameters on the level of root colonization of Molinia caerulea and (ii) to relate root colonisation parameters and soil variables to Molinia caerulea abundance in two contrasting habitats (grasslands and heavy metal contaminated sites). The sites differ significantly in terms of bio-available heavy metal contents, particularly Zn (34 times more than grasslands), soil texture, CaCO 3 , organic matter (LOI%), Mg and nitrate content. Principal Component Analysis showed the strong negative correlations between frequency of mycorrhization (F), arbuscular abundance (A%) and intensity of root cortex colonisation (M%) and concentration of bioavailable Zn and Cd. Moreover, no positive correlation between root colonization of Molinia and its abundance was found. The frequency of mycorrhization of root fragments (F%) was only slightly different between these two habitats, whereas the intensity of root cortex colonisation (M%) and relative arbuscular abundance (A%) were significantly lower (3 and 4 times respectively) on the post-industrial sites. The bioavailable Zn content in the substratum of post-industrial sites was strongly negatively correlated with species richness, Shannon diversity index and Evenness. In contrast, these relationships were not statistically significant in grasslands. Based on obtained results we could draw a model of possible relationships between root colonization of Molinia, HM content and Molinia abundance on grasslands and post-industrial sites. Bioavailable Zn content in the soil is a one of main factors influencing the Molinia community diversity. In the grasslands, lower amounts of bioavailable Zn, resulted in higher species richness (R) and species diversity (H) which in turn lead to higher root colonization. On the other hand, on the post-industrial sites, the elevated bioavailable Zn content strongly decreases the plant species richness (R) and species diversity (H) and this caused the decline in root colonization parameters. The low species richness on Zn-polluted sites allowed Molinia to reach higher abundance since the competition with other species is reduced.

The forests of Bhadrachalam, Kothagudem and Paloncha of Khammam District in Andhra Pradesh, India during were surveyed 2007-2010 for micro-and macro-fungi colonizing litter, fruit, bark, humid soils, wood, dung and water, which revealed 131 species associated with diversified substrates of which 96 were micro-fungi and 35 being macro-fungi. Thirty four fungi were cultured, while the remaining could not be cultured. Sixty five species were found colonizing litter, whereas the rest were associated with other habitats of Bhadrachalam forest. Anamorphic fungi dominated the mycofloristics followed by Basidiomycotina. Mastigomycotina, Zygomycotina and Ascomycotina members.

The effect of four fungicides on alkaline phosphatase (ALP) activity in internal and external hyphae of an arbuscular mycorrhizal (AM) fungus was examined. Four-week-old plants were treated with an aqueous solution of the fungicides and then harvested 3 days later. Fungicides were applied at a low and a high level corresponding to 1 and 100 times the recommended field application dose. The

Rose-scented geranium (Pelargonium sp.) is a highly valued aromatic crop. Its growth is limited by soil salinity and sodicity stress. Arbuscular mycorrhizal (AM) fungus, phosphate-solubilizing bacteria (PSB), and P fertilizers may enhance the growth and secondary metabolism in geranium plants. In this context, a pot experiment was conducted to study the effects of PSB, AM fungi (Glomus intraradices), and P fertilizer on the yield, chemical composition of essential oil, and mineral element acquisition of geranium. The dry matter yield of shoot and essential oil yield, and mineral element (P, K, Ca, Mg, Na, Fe, Cu, and Zn) uptake in shoot tissues of geranium were significantly increased by the inoculation with AM fungi, co-inoculation with AM fungi and PSB, and P fertilization as compared to control. While the co-inoculation of geranium with AM fungi and PSB significantly enhanced the content of the monoterpenes such as citronellol, geraniol, geranial, and a sesquiterpene (10-epi-γ eudesmol), the P fertilization only enhanced the content of a sesquiterpene, 10-epi-γ eudesmol in the volatile oil. We conclude that the co-inoculation of PSB and AM fungi could be the best natural alternative to phosphate fertilizers to enhance the yield and quality of essential oil from geranium plants grown in sodic soils.

The paper presents the results of research on cacti such as Gymnocalycium baldianum, Gymnocalycium mihanovichii, Notocactus eugeniae and Notocactus leninghausii, aimed at improving plant growth and defense against the pathogenic fungus Fusarium sp., through the use of Gigaspora margarita inoculated in the growing medium. Objectives of the work were: i) use Gigaspora margarita to assess if the use of arbuscular mycorrhizae can lead to an increase in the growth rate of Notocactus and Gymnocalycium, plants generally slow in their growth cycle; ii) to evaluate if the use of mycorrhizae can lead to an extension of the duration of the flower, to promote pollination of bees; iii) to assess if the use of Gigaspora Margarita allows greater protection of the roots against the fungus Fusarium sp. which often affects the roots of these cacti. The two experimental groups in cultivation were: i) group without arbuscular michorriza, irrigated with water and substrate previously fertilized; group with Gigaspora Margarita, irrigated with water and substrate previously fertilized. All plants treated with Gigaspora margarita showed a significant increase in plant height and circumference, vegetative and root weight of the plants, number of new suckers, number of flowers and fruits and flower life. In addition, there was significant control of the fungus Fusarium sp. in plants in which Gigaspora margarita was inoculated into the substrate, in fact a reduced infection of the roots due to this pathogen was found. The application of mycorrhiza in the cultivation of plants can guarantee the possibility to obtain a higher quality product, a higher resistance to biotic stress, an increase in growth rate, very interesting aspects in the succulent and cactus plants sector.

A field experiment was conducted to study the effects of inoculation with the arbuscular mycorrhizal fungus Glomus caledonium and/or Rhizobium meliloti on phytoremediation of an agricultural soil contaminated with weathered PCBs by alfalfa grown for 180 days. Planting alfalfa (P), alfalfa inoculated with G. caledonium (P+AM), alfalfa inoculated with R. meliloti (P+R), and alfalfa co-inoculated with R. meliloti and G. caledonium (P+AM+R) decreased significantly initial soil PCB concentrations by 8.1, 12.0, 33.8, and 43.5%, respectively. Inoculation with R. meliloti and/or G. caledonium (P+AM+R) increased the yield of alfalfa, and the accumulation of PCBs in the shoots. Soil microbial counts and the carbon utilization ability of the soil microbial community increased when alfalfa was inoculated with R. meliloti and/or G. caledonium. Results of this field study suggest that synergistic interactions between AMF and Rhizobium may have great potential to enhance phytoremediation by alfalfa of an agricultural soil contaminated with weathered PCBs.

Singh AK, Jamaluddin (2011) Status and diversity of arbuscular mycorrhizal fungi and its role in natural regeneration on limestone mined spoils. Biodiversitas 12: 107-111. Limestone mined spoils are devoid of adequate population of beneficial microbial flora. Arbuscular mycorrhizal fungi (AMF) are very important constituent of plant- soil-microbe system. In mined spoils the population of AMF is greatly reduced and hence the spoils become very inhospitable for establishment of vegetation. In the present investigation, status of AMF population and its effect on natural regeneration process is studied. It is well known fact that the arbuscular mycorrhizalfungi play very important role in establishment of vegetation in degraded lands. Plantation of seedlings inoculated with arbuscular mycorrhizal fungi provide favorable soil conditions for naturally growing vegetation in the mined overburden spoils. Physico-chemical properties of soil are converted suitable for planted species and thus ...

Field experiment was conducted from December to April 2013 at the Botanical Nursery, University
of  Ibadan,  Nigeria.  The  aim  of  this  study  was  to  investigate  the  interactive  effects  of  arbuscular
mycorrhizal  fungus  (Glomus  mosseae),spent  mushroom  compost  (Pleurotus  pulmonarius)  and
poultry  manure    on  drought  tolerance  and  leaf  curl  resistance  of  okra  (Abelmoschus  esculentus)
genotypes; NG/TO/02/12/156, NG/OA/03/12/157, NG/OA/05/12/159, IJ-OND Okr 1 and IJ-OND
Okr2.  The  treatments  were  laid  out  factorially  in  a  complete  randomized  design  with  three
replications. The result shows that the  effect of replicating  okra accessions and the interactions of
replicate x treatment  were  non- significant (P>0.01) for all  yield traits, drought tolerance and leaf
curl resistance. 
On the other hand, the bio-inoculants treatment was highly resistant to viral leaf curl  and drought,
while  the  effects  of  replicate  and  interactions  of  replicate  x  treatment  were  not  significant.  The
resistance ability to drought effect in second replicate was significantly different from the first and
third replicates which are not significantly different from each other, but the drought tolerance at 2
and 4 WAP  were significantly higher than at 6 WAP. There  was no significant  effect of replicate
and different growth stages on leaf curl infection. The combination of  G. mosseae, P. pulmonarius
and Poultry  manure treated plants for drought tolerance and leaf curl resistance  were significantly
higher  than  the  other  treatments  including  the  control,  while  the  combination  of    P.  pulmonarius
and Poultry manure was the most resistant to leaf curl infection. Therefore, AMF treated plants and
their interactions with other bio-inoculants influenced the drought tolerance and leaf curl resistance
compared to untreated plants.

Knowledge and conservation of diversity in symbiotic arbuscular mycorrhizal fungi is of crucial importance for their efficient use in environmental conservation and sustainable plant production systems. The recalcitrance of these microorganisms to pure culture, and the absence of information about plasmogamy, karyogamy or meiosis, means that information about the genetical bases of any variations in their population biology ecological specificity or symbiotic activity is generally lacking. A multidisciplinary approach is necessary to identify significant differences between populations, species or isolates. An overview is presented of some of the morphological, biological and molecular aspects of arbuscular mycorrhizal fungi that may contribute to defining and understanding biodiversity in this group of symbiotic microorganisms.

... labile P sources (Bolan, 1991 and Hernández et al., 2000), but other studies demonstrated that mycorrhizal plants obtained P from normally unavailable sources of Pi and Po (Bolan et al., 1987, Jayachandran et al., 1989, Jayachandran et al., 1992, Koide and Kabir, 2000 and ...

The effect of arbuscular mycorrhizal fungi (AMF) on industrial tomato (Lycopersicon esculentum Mill. cv. Isma F1) cultivated in NorthEastern Algeria was evaluated under greenhouse and field conditions in a vertisol soil intended for the cultivation of industrial tomato. In the greenhouse, a commercial AMF inoculum and native fungal isolates consisting of Funneliformis mosseae and Septoglomus constrictum, were added in sterilized or non-sterilized soil and tested for their effects on the growth of tomato. Inoculation with exotic AMF in the commercial inoculum or with native isolates had similar effects in increasing mycorrhizal root colonization rates and tomato growth. In the field, the commercial AMF inoculant was combined with three rates of chemical fertilizer used for the cultivation of industrial tomato (mono-ammonium phosphate, ammonium sulphate and NPK, applied at 0, 50 and 100% of the recommended dose). Introduced AMF significantly improved mycorrhizal root colonization levels, growth and yield as compared to the indigenous AMF alone. In addition, in the presence of the mycorrhizal inoculant, an application of 50% of recommended fertilizer dose provided the same yield as the full fertilizer dose without inoculation. Results clearly show that in this soil, plants needed both fertilization and AMF inoculation to achieve optimal growth and yield, and that the application of AMF can compensate for the reduction in chemical fertilizers, offering a more sustainable farming system that is respectful of the environment.

We developed a reliable, inexpensive, and simple method for staining arbuscular-mycorrhizal fungal colonizations in root tissues. Apart from applications in research, this nontoxic, high-quality staining method also could be of great utility in teaching exercises. After adequate clearing with KOH, an ink-vinegar solution successfully stained all fungal structures, rendering them clearly visible.

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 ...

The effect of arbuscular mycorrhizal fungi (AMF) on industrial tomato (Lycopersicon esculentum Mill. cv. Isma F1) cultivated in NorthEastern Algeria was evaluated under greenhouse and field conditions in a vertisol soil intended for the cultivation of industrial tomato. In the greenhouse, a commercial AMF inoculum and native fungal isolates consisting of Funneliformis mosseae and Septoglomus constrictum, were added in sterilized or non-sterilized soil and tested for their effects on the growth of tomato. Inoculation with exotic AMF in the commercial inoculum or with native isolates had similar effects in increasing mycorrhizal root colonization rates and tomato growth. In the field, the commercial AMF inoculant was combined with three rates of chemical fertilizer used for the cultivation of industrial tomato (mono-ammonium phosphate, ammonium sulphate and NPK, applied at 0, 50 and 100% of the recommended dose). Introduced AMF significantly improved mycorrhizal root colonization leve...