Fungus Glomus Deserticola Research Articles

Healthy Response from Chromium Survived Pteridophytic Plant-Ampelopteris prolifera with the Interaction of Mycorrhizal Fungus-Glomus deserticola

Interaction between arbuscular mycorrhizal fungus Glomus deserticola and pteridophytic member Ampelopteris prolifera was found abundant on entire growth level based on elemental composition and gaseous exchange as a potential remediation system for phytoextraction of chromium. Inoculated A. prolifera (AM) and non-inoculated A. prolifera (Non-AM) were supplied with two Cr species: 12 mmol of trivalent cation (Cr+3) [Cr(III)] and 0.1 mmol of divalent dichromate anion (Cr2O7 −2) [Cr(VI)]. Both Cr species were found to be depressed in overall growth and inefficient stomatal conductance (gs) and net photosynthesis (NP). Mycorrhizal association was found to be natural scavenger of Cr toxicity as indicated by greater growth in plants exposed to Cr species, and increased gas exchange of Cr(III) treated plants. Though, chromium reduction resulted lower level of nitrogen (N), phosphorus (P), and potassium (K) but interestingly elevated the level of aluminum (Al), iron (Fe), and zinc (Zn) uptake in many folds which is the significance of sustainable growth of plant.

Effects of inoculation with stress-adapted arbuscular mycorrhizal fungus Glomus deserticola on growth of Solanum melogena L. and Sorghum sudanese Staph. seedlings under salinity and heavy metal stress conditions

The beneficial effects of a Glomus deserticola strain isolated from the rhizosphere of grasses (belonging to Poaceae family) growing along the industrial waste from a distillery were investigated under stress conditions. The study was conducted to assess the efficacy of the arbuscular mycorrhizal (AM) fungal ecotype in salinity and heavy metal (HM) tolerance of eggplant (Solanum melongena L.) in soils amended with various stress levels of NaCl, zinc and cadmium. Mycorrhizal (M) seedlings produced a significantly (p < 0.05) greater growth response and were more tolerant to salt and HM stresses than nonmycorrhizal (NM) seedlings in all treatments. The HM contents in the plant tissues were significantly higher in M than NM eggplants. Furthermore, when the efficacy was compared with other AM isolates in HM-polluted soils with Sudan grass (Sorghum sudanese Staph.) as a test plant, the AM ecotype responded best to these soils, as evident from the significantly greater growth response and its aggressiveness in colonizing roots in all soil types tested. These results suggest that this G. deserticola ecotype can be used as an effective tool to alleviate the adverse effects of excessive salinity and HM toxicity on plant growth. Finally, the isolate may have potential in the bioremediation of polluted soils.

Improving growth, flower yield, and water relations of snapdragon (Antirhinum majus L.) plants grown under well-watered and water-stress conditions using arbuscular mycorrhizal fungi

The influence of arbuscular mycorrhizal (AM) fungus Glomus deserticola (Trappe and John) on plant growth, nutrition, flower yield, water relations, chlorophyll (Chl) contents and water-use efficiency (WUE) of snapdragon (Antirhinum majus cv. butterfly) plants were studied in potted culture under well-watered (WW) and water-stress (WS) conditions. The imposed water stress condition significantly reduced all growth parameters, nutrient contents, flower yield, water relations, and Chl pigment content and increased the electrolyte leakage of the plants comparing to those of nonstressed plants. Regardless of the WS level, the mycorrhizal snapdragon plants had significantly higher shoot and root dry mass (DM), WUE, flower yield, nutrient (P, N, K, Mg, and Ca) and Chl contents than those nonmycorrhizal plants grown both under WW or WS conditions. Under WS conditions, the AM colonization had greatly improved the leaf water potential (Ψw), leaf relative water content (RWC) and reduced the leaf electrolyte leakage (EL) of the plants. Although the WS conditions had markedly increased the proline content of the leaves, this increase was significantly higher in nonmycorrhizal than in mycorrhizal plants. This suggests that AM colonization enhances the host plant WS tolerance. Values of benefit and potential dry matter for AM-root associations were highest when plants were stressed and reduced under WW conditions. As a result, the snapdragon plants showed a high degree of dependency on AM fungi which improve plant growth, flower yield, water relations particularly under WS conditions, and these improvements were increased as WS level had increased. This study confirms that AM colonization can mitigate the deleterious effect of water stress on growth and flower yield of the snapdragon ornamental plant.

The effects of the arbuscular mycorrhizal fungusGlomus deserticola on growth of tomato plants grown in the presence of olive mill residues modified by treatment with saprophytic fungi

Olive oil extraction generates large amounts of olive mill residues (DOR) which may be used as fertilizer. The influence of arbuscular mycorrhizal (AM) on the phytotoxicity of dry olive residue (DOR) transformed with saprophytic fungi was studied. Aqueous extraction of DOR gave an (ADOR) fraction and an exhausted (SDOR) fraction, both of which had less phytotoxicity for tomato than the original DOR. The saprophytic fungiTrametes versicolor andPycnoporus cinnabarinus further decreased the phytotoxicity of ADOR and SDOR on tomato. The decrease of phenols concentration and the differences in the level of laccase activity caused by these fungi suggest did not account fully for the reduced phytoxicity but the fact that the higher hydrolytic enzyme activity ofP. cinnabarinus, paralleled the decrease of phytotoxicity, indicates that these enzymes seem to be involved. The AM fungusGlomus deserticola increased or exacerbated the beneficial effect of SDOR incubated with saprophytic fungi, in terms of dry weight of tomato plants. The percentage of root length colonized byG. deserticola strongly decreased in presence of DOR, but the level of mycorrhization was higher in presence of ADOR or SDOR. Our results suggest that the combination of aqueous extraction and incubation with saprophytic fungi will open the way for the use of olive oil extraction residues as organic amendment in agricultural soils.

Interactions of Trametes versicolor, Coriolopsis rigida and the arbuscular mycorrhizal fungus Glomus deserticola on the copper tolerance of Eucalyptus globulus

The presence of high levels of Cu in soil decreases the shoot and root dry weights of Eucalyptus globulus. However, higher plant tolerance of Cu has been observed in the presence of the arbuscular mycorrhizal (AM) fungus Glomus deserticola. The hyphal length of G. deserticola was sensitive to low Cu concentrations, and the percentage of AM root colonisation and the metabolic activity of the AM fungus were also decreased by Cu. Therefore, a direct effect of Cu on the development of the AM fungus inside and outside the root cannot be ruled out. E. globulus colonised by G. deserticola had higher metal concentrations in the roots and shoots than do non-mycorrhizal plants; however, the absence of a higher root to shoot metal ratio in the mycorrhizal plants (1.70 ± 0.11) indicated that G. deserticola did not play a filtering/sequestering role against Cu. The saprobe fungi Coriolopsis rigida and Trametes versicolor were able to remove Cu ions from the asparagine–glucose growth media. However, plants inoculated with C. rigida and T. versicolor did not accumulate more Cu than non-inoculated controls, and the growth of the plant was not increased in the presence of these fungi. However, C. rigida increased the shoot dry weight, AM root length colonisation, and metabolic mycelial activity of plants colonised with G. deserticola in the presence of Cu; only this saprobe-AM fungus combination increased the tolerance of E. globulus to Cu. Inoculation with G. deserticola and C. rigida increased the E. globulus Cu uptake to levels reached by hyperaccumulative plants.

Contribution of the saprobic fungi Trametes versicolor and Trichoderma harzianum and the arbuscular mycorrhizal fungi Glomus deserticola and G. claroideum to arsenic tolerance of Eucalyptus globulus

The presence of high concentrations of arsenic (As) decreased the shoot and root dry weight, chlorophyll and P and Mg content of Eucalyptus globulus colonized with the arbuscular mycorrhizal (AM) fungi Glomus deserticola or G. claroideum, but these parameters were higher than in non-AM plants. As increased the percentage of AM length colonization and succinate dehydrogenase (SDH) activity in the root of E. globulus. Trichoderma harzianum, but not Trametes versicolor, increased the shoot and root dry weight, chlorophyll content, the percentage of AM root length colonization and SDH activity of E. globulus in presence of all As concentrations applied to soil when was inoculated together with G. claroideum. AM fungi increased shoot As and P concentration of E. globulus to higher level than the non-AM inoculated controls. The contribution of the AM and saprobe fungi to the translocation of As from root to shoot of E. globulus is discussed.

Pseudomonads and symbiotic micro-organisms as biocontrol agents against fungal disease caused by Pythium aphanidermatum

Experiments were undertaken to assess the antagonistic aptitude of Pseudomonas spp. alone or associated with mycorrhizal fungi on Pythium aphanidermaturm, the causal agent of seedlings damping-off and stem rot of cowpea (Vigna unguiculata L. Walp). Evaluation was made using selected strains of pseudomonad (Pseudomonas fluorescens, P. putida and Pseudomonas sp.) isolated from V. unguiculata andSolanum tuberosum rhizospheric soils collected in three agroecological zones of Cameroon. Cultures were conducted on agar plates and in liquid media to evaluate the antagonistic capacity of those strains against Pythium aphanidermaturm and to evaluate their biocontrol activity in protecting cowpea plants. The results showed a direct inhibition of the pathogenic fungus by these bacteria. P. fluorescens used alone against Pythium aphanidermaturm, provided a reduction of the disease index from 3.44 to 1.06. When the arbuscular mycorrhizal fungi Glomus deserticola is associated to P. fluorescens, the disease index dropped to 0.13, confirming the synergistic effect of those beneficial micro-organisms. Key words: antagonism, beneficial micro-organisms, biological control, Glomus deserticola, Pseudomonas spp., Pythium aphanidermaturm.

Pseudomonads and symbiotic micro-organisms as biocontrol agents against fungal disease caused by

Experiments were undertaken to assess the antagonistic aptitude of Pseudomonas spp. alone or associated with mycorrhizal fungi on Pythium aphanidermaturm, the causal agent of seedlings dampingoff and stem rot of cowpea (Vigna unguiculata L. Walp). Evaluation was made using selected strains of pseudomonad (Pseudomonas fluorescens, P. putida and Pseudomonas sp.) isolated from V. unguiculata and Solanum tuberosum rhizospheric soils collected in three agroecological zones of Cameroon. Cultures were conducted on agar plates and in liquid media to evaluate the antagonistic capacity of those strains against Pythium aphanidermaturm and to evaluate their biocontrol activity in protecting cowpea plants. The results showed a direct inhibition of the pathogenic fungus by these bacteria. P. fluorescens used alone against Pythium aphanidermaturm, provided a reduction of the disease index from 3.44 to 1.06. When the arbuscular mycorrhizal fungi Glomus deserticola is associated to P. fluorescens, the disease index dropped to 0.13, confirming the synergistic effect of those beneficial micro-organisms.

Variations in water status, gas exchange, and growth in Rosmarinus officinalis plants infected with Glomus deserticola under drought conditions

The influence of the arbuscular mycorrhizal fungus Glomus deserticola on the water relations, gas exchange parameters, and vegetative growth of Rosmarinus officinalis plants under water stress was studied. Plants were grown with and without the mycorrhizal fungus under glasshouse conditions and subjected to water stress by withholding irrigation water for 14 days. Along the experimental period, a significant effect of the fungus on the plant growth was observed, and under water stress, mycorrhizal plants showed an increase in aerial and root biomass compared to non-mycorrhizal plants. The decrease in the soil water potential generated a decrease in leaf water potential (psi(l)) and stem water potential (psi(x)) of mycorrhizal and non-mycorrhizal plants, with this decrease being lower in mycorrhizal water-stressed plants. Mycorrhization also had positive effects on the root hydraulic conductivity (Lp) of water stressed plants. Furthermore, mycorrhizal-stressed plants showed a more important decrease in osmotic potential at full turgor (psi(os)) than did non-mycorrhizal-stressed plants, indicating the capacity of osmotic adjustment. Mycorrhizal infection also improved photosynthetic activity (Pn) and stomatal conductance (g(s)) in plants under water stress compared to the non-mycorrhizal-stressed plants. A similar behaviour was observed in the photochemical efficiency of PSII (Fv/Fm) with this parameter being lower in non-mycorrhizal plants than in mycorrhizal plants under water stress conditions. In the same way, under water restriction, mycorrhizal plants showed higher values of chlorophyll content than did non-mycorrhizal plants. Thus, the results obtained indicated that the mycorrhizal symbiosis had a beneficial effect on the water status and growth of Rosmarinus officinalis plants under water-stress conditions.

Soil Amendment with Different Peatmosses Affects Mycorrhizae of Onion

Formation of arbuscular mycorrhizae (AM) has been inhibited in soilless potting mixes that usually contain some proportion of peat moss. The cause of the inhibition has been thought to be high fertilizer P content in the media that suppresses spread of the fungal symbiont in the root tissue. However, there has also been some suggestion that the peats themselves may contribute to the inhibition. That possibility was explored in this study. A sandy-loam soil, in which mycorrhizae consistently enhance plant growth under P-limiting conditions, was amended with six different peats. Onions (Allium cepa 'White Lisbon'), as an indicator host, were grown in the mixes under P-limiting conditions, and were inoculated or not with the AM fungi Glomus deserticola or Gigaspora rosea. Plant growth response to inoculation with AM fungi (AMF) varied with the type of peat and AMF isolate. Inoculated plants generally had the highest root biomass when grown in soil amended with peat. Root colonization by the two fungal symbionts was also affected differently by different peat amendments. Root colonization by Glomus deserticola and Gigaspora rosea was inhibited by at least half of the peat types. However, the types of peat inhibitory to Gigaspora rosea colonization were not the same as those inhibitory to Glomus deserticola colonization. These results indicate that different peat amendments can suppress or enhance mycorrhiza formation on onion roots and resultant growth benefit under P-limiting conditions, depending on the mycorrhizal fungus used.

Mycorrhizal fungi influence competition in a wheat-ryegrass association treated with the herbicide diclofop

Vesicular-arbuscular mycorrhizal (VAM) fungi interconnect the root systems of adjacent plants, and mediate the transfer of nutrients between them. The objective of this study was to determine if the VAM fungus Glomus deserticola Trappe, Bloss and Menge enhanced such a transfer in a crop-weed association when one associated plant was selectively weakened by an herbicide. Wheat ( Triticum aestivum L.) or perennial ryegrass ( Lolium perenne L.) plants were grown with or without VAM fungi either in monocultures, or together as an intercrop for 7 weeks, when the herbicide diclofop was applied as a soil drench at dose rates of 0%, 10%, 50%, 100% and 1000% of the field recommendation (0.9 kg ha −1). Seed yield at harvest (13 weeks) was significantly greater for the + VAM than for the − VAM intercropped wheat plants at all dose rates. When grown in monoculture, wheat yield was greater in the − VAM plants. Shoot growth of intercropped + VAM wheat was enhanced, while that of ryegrass was inhibited. In monoculture, the plant dry masses of both − VAM wheat and ryegrass were greater than those of the + VAM plants, while in intercrop the + VAM wheat plants fared better. The data showed that (1) the herbicide inhibited root colonization by G. deserticola in wheat but not in ryegrass, and (2) when grown together, wheat growth and yield were enhanced and ryegrass growth was inhibited in + VAM herbicide-treated associations. We interpret the findings as a change in interplant source-sink relations upon treatment with diclofop: ryegrass roots became sources of nutrients to the tolerant wheat roots (stronger sinks), and the transfer process was enhanced by the VAM mycelium common to both.

Hyphal contribution to water uptake in mycorrhizal plants as affected by the fungal species and water status

Vesicular‐arbuscular mycorrhizae may increase resistance of plants to drought by a number of mechanisms, such as increased root hydraulic conductivity, stomatal regulation, hyphal water uptake and osmotic adjustment. However, a substantial contribution of vesicular‐arbuscular mycorrhizal (VAM) hyphae to water uptake has not been demonstrated unequivocally. The objective of this investigation was to examine the contribution of hyphae from two VAM fungi to water uptake and transport by the host plant. Lettuce (Lactuca sativa L.) plants were grown in a container divided by a screen into two compartments. One was occupied by roots, the other only by VAM hyphae, which the screen permitted to pass. Roots were colonized by the VAM fungi Glomus deserticola or Glomus fasciculatum, or were left uninoculated but P‐supplemented. Water was supplied to the hyphal compartment at a distance of 10 cm from the screen (root). CO2 exchange rate, water‐use efficiency, transpiration, stomatal conductance and photosynthetic phosphorus‐use efficiency of VAM or P‐amended control plants were evaluated at three levels of water application in the hyphal compartment. Results indicate that much of the water was taken up by the hyphae in VAM plants. VAM plants, which had access to the hyphal compartment, had higher water and nutrient contents. G. deserticola functioned efficiently under water limitation and mycelium from G. fasciculatum‐colonized plants was very sensitive to water in the medium. This discrepancy in VAM behaviour reflects the various abilities of each fungus according to soil water levels. Different abilities of specific mycelia were also expressed in terms of nutritional and leaf gas‐exchange parameters. G. fasciculatum caused a significant increase in net photosynthesis and rate of water use efficiency compared to G. deserticola and P‐fertilized plants. In contrast, the G. deserticola treatment was the most efficient affecting N, P and K nutrition, leaf conductance and transpiration. Since no differences in the intra‐ and extra‐radical hyphal extension of the two endophytes were found, the results demonstrate that mycorrhizal hyphae can take up water and that there are considerable variations in both the behaviour of these two VAM fungi and in the mechanisms involved in their effects on plant water relations.

Mycorrhiza and Repeated Drought Exposure Affect Drought Resistance and Extraradical Hyphae Development of Pepper Plants Independent of Plant Size and Nutrient Content

Summary Pepper ( Capsicum annuum L.) plants with and without VA-mycorrhiza (formed by the fungus Glomus deserticola Trappe, Bloss & Menge), VAM, and NVAM, respectively, were drought acclimated (DA) by four drought cycles or kept well watered (NDA). All plants were then subjected to an additional drought cycle. Similar shoot mass and leaf area were achieved in all treatments by giving more P fertilizer to NVAM than VAM plants. With few exceptions, leaf nutrient concentrations of 12 elements, including P, were either equal or higher in NVAM than VAM plants. During peak drought stress, plants with the combination of VAM-DA treatments had the greatest drought resistance, as indicated by the highest leaf water potential, turgor, relative water content and frequency of non-wilted plants. Some drought resistance, as indicated by intermediate frequency of wilting, occurred when VAM or DA were applied singly. Nutrition and plant size were not associated with this drought resistance. Extraradical hyphae development and soil aggregation of VAM plants were enhanced by drought acclimation, suggesting that these hyphae improved drought resistance by facilitating soil water uptake.

Short term effects of phosphorus and VA-mycorrhizal fungi on nutrition, growth and development of Capsicum annuum L.

Seedlings of Capsicum annuum L. cultivar ‘Early Bountiful’ were grown in containers of river sand inoculated or not with the VA-mycorrhizal (VAM) fungus Glomus deserticola (Trappe, Bloss & Menge). Long Ashton Nutrient Solution (LANS) were modified to supply P at 11, 22 or 44 μg ml −1. After 42 days, plants were evaluated for growth, development and leaf elemental content. Short term effects occurred with P and VAM treatment. Increasing P fertility enhanced fruit number, leaf area, shoot, fruit and root dry weight, and decreased leaf area ratio (LAR). VAM increased leaf area of plants fertilized with full strength LANS (44 μg ml −1 P). VAM generally increased leaf tissue B, but decreased Mo. Tissue K and N in VAM plants was not decreased, as it was in non-mycorrhizal plants with increasing P fertility. Increasing P fertility generally decreased tissue Cu and Zn and increased P levels. Mycorrhizal colonization (% root length) and spores recovered per unit of soil were greater with plants fertilized with 11 than 44 μg ml −1 P levels.

Effects of Va mycorrhizae on growth and mineral uptake of sorghum grown at varied levels of soil acidity

Abstract The effects of the vesicular‐arbuscular mycorrhizal (VAM) fungus Glomus deserticola (Trappe, Bloss, and Menge) on growth and mineral element uptake of sorghum [Sorghum bicolor (L.) Moench] were investigated in greenhouse experiments with acid Cecil sandy clay loam (clayey, kaolinitic, thermic, Typic Hapludults) at five pH values (4.1 to 5.8). Control experiments consisted of sterile VAM inocula. Dry matter yields and mineral element uptake were markedly depressed at pH 4.1, were relatively high at pH 4.5, and remained fairly constant from pH 4.5 to 5.8 in mycorrhizal plants. Dry matter yields, root lengths, and mineral element contents of nonmycorrhizal plants increased as soil pH increased, and these characteristics were similar to mycorrhizal plants only after the soil was above pH 5.0 to 5.5. Mycorrhizal plants had higher total and efficiency uptake of mineral elements (shoot element content/root dry matter ratio) than nonmycorrhizal plants. Available Al in acid soils may have been detrimental...

Osmotic Adjustment in Leaves of VA Mycorrhizal and Nonmycorrhizal Rose Plants in Response to Drought Stress

Osmotic adjustment in Rosa hybrida L. cv Samantha was characterized by the pressure-volume approach in drought-acclimated and unacclimated plants brought to the same level of drought strain, as assayed by stomatal closure. Plants were colonized by either of the vesicular-arbuscular mycorrhizal fungi Glomus deserticola Trappe, Bloss and Menge or G. intraradices Schenck and Smith, or were nonmycorrhizal. Both the acclimation and the mycorrhizal treatments decreased the osmotic potential (Psi(pi)) of leaves at full turgor and at the turgor loss point, with a corresponding increase in pressure potential at full turgor. Mycorrhizae enabled plants to maintain leaf turgor and conductance at greater tissue water deficits, and lower leaf and soil water potentials, when compared with nonmycorrhizal plants. As indicated by the Psi(pi) at the turgor loss point, the active Psi(pi) depression which attended mycorrhizal colonization alone was 0.4 to 0.6 megapascals, and mycorrhizal colonization and acclimation in concert 0.6 to 0.9 megapascals, relative to unacclimated controls without mycorrhizae. Colonization levels and sporulation were higher in plants subjected to acclimation. In unacclimated hosts, leaf water potential, water saturation deficit, and soil water potential at a particular level of drought strain were affected most by G. intraradices. G. deserticola had the greater effect after drought preconditioning.