Arbuscular Mycorrhizal Fungus Glomus Fasciculatum Research Articles

Management of chromium(VI)-contaminated soils through synergistic application of vermicompost, chromate reducing rhizobacteria and Arbuscular mycorrhizal fungi (AMF) reduced plant toxicity and improved yield attributes in Ocimum basilicum L.

An integrated approach involving vermicompost, chromate reducing bacteria and AMF was tested to manage the toxic impacts of Cr(VI) on Ocimum basilicum as a model plant. Pot experiments were conducted on O. basilicum plants in an artificially Cr(VI)-contaminated soil in two phases of experiment as bioinoculants experiment and vermicompost experiment. In the first phase of the bioinoculants experiment the series of gradient concentrations of Cr(VI) (0, 25, 50 and 100 mg kg–1 in soil) were evaluated with previously isolated four efficient Cr(VI)-reducing rhizo-bacterial strains (Bacillus Cereus strain SUCR 44, BC; Microbacterium sp. strain SUCR 140, MB; Bacillus thuringiensis strain SUCR186, BT; and Bacillus subtilis strain SUCR188; BS) along with Arbuscular Mycorrhizal Fungus—Glomus fasciculatum (GF) in alone and in co-inoculation form. In the second experiment (vermicompost) the best performing strain (MB) was tested alone or in combination with GF along with different doses of vermicompost. It was observed that vermicompost by itself could be useful in decreasing the bioavailable Cr(VI), uptake of Cr besides improving the nutritional status of plants. The vermicompost also played an important and indirect role and improved herb yield by supporting the multiplication of MB (Microbacterium sp.), an efficient chromate reducing rhizobacteria, that further decreased the bioavailable and toxic form of Cr and improved population and colonization of GF too. The translocation of Cr(VI) was averted through improved colonization of GF, also prevented higher accumulation of Cr in aerial parts (leafy herb) of O. basilicum.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00203-022-03230-z.

Glomus fasciculatum in defense responses to fusarial wilt of Coleus forskohlii

The activities of enzymes responsible for disease resistance in Coleus forskohlii, pre-inoculation with an arbuscular mycorrhizal fungus, Glomus fasciculatum, and/or infection with a pathogenic strain of Fusarium oxysporum, and the biological control effect of G. fasciculatum on fusarial wilt in Coleus forskohlii were investigated. The experiment was carried out with four treatments, viz. plants pre-inoculated with G. fasciculatum, plants pre-inoculated with G. fasciculatum followed by infection with F. oxysporum, plants infected with F. oxysporum, and plants without any of the two microorganisms. Mycorrhization (%) was reduced in pathogen-challenged plants. In G. fasciculatum- and F. oxysporum- treated plants, an increase in phenolic content was observed on the 20th day while the maximum increase in phenylalanine ammonia-lyase activity was observed on the 15th day after challenge inoculation with F. oxysporum compared with that of other treatments. In G. fasciculatum- and F. oxysporum-treated plants, an increase in peroxidase and polyphenol oxidase activity was observed on the 15th day after pathogen challenge compared with that of other treatments. The observation revealed that the arbuscular mycorrhizal fungus Glomus fasciculatum systemically induced resistance against wilt disease of Coleus forskohlii via production of phenolics, the defence enzymes phenylalanine ammonia-lyase and polyphenol oxidase, and pathogenesis-related proteins, and peroxidase in response to Fusarium oxysporum infection. G. fasciculatum reduced the disease severity and promoted plant growth significantly (P<0.05) in single-treated and in combination with F. oxysporum-treated plants compared with control plants. The results suggested that G. fasciculatum is a potentially effective protection agent against F. oxysporum.

“Changes in antioxidant activity in Gmelina arborea (Verbenaceae) inoculated with Glomus fasciculatum under drought stress”

Gmelina arborea Roxb. seedlings were inoculated with arbuscular mycorrhizal fungi Glomus fasciculatum in a drought stress experiment. Irrigation was withheld after 30 days of AM inoculation and drought period were started. Control plants (non-AM and AM plants) were irrigated. Gmelina inoculated with Glomus fasciculatum grown under drought stress showed a significant increase in various morphological parameters like shoot and root length, fresh and dry weight as compared to non-AM inoculated Gmelina plants. Besides this, antioxidant activities (superoxide dismutase, guiacol peroxidase and catalase) were found to protect plants from drought stress. The relevance of the activities of these enzymes to drought stress indicates that AM inoculated Gmelina plants are found to be tolerant compared to non-AM inoculated Gmelina plants, which led us to conclude that AM treated Gmelina plants are sturdier and adaptive to stress conditions. These findings also suggest that association improves plant–water relations and contributes to drought tolerance in forest trees.

Effect of root exudates of mycorrhizal tomato plants on microconidia germination of Fusarium oxysporum f. sp. lycopersici

The effect of root exudates from mycorrhizal and non-mycorrhizal tomato plants on microconidia germination of the tomato pathogen Fusarium oxysporum f. sp. lycopersici was tested. Microconidia germination was enhanced in the presence of root exudates from mycorrhizal tomato plants. Tomato plants were colonised by the arbuscular mycorrhizal fungus Glomus fasciculatum, indicating that alterations of the exudation pattern depended on the degree of root AM colonisation. Testing the exudates from plants with a high and a low P level revealed that the alterations of the root exudates from mycorrhizal plants, resulting in a changed effect on microconidia germination, are not due to an improved P status of mycorrhizal plants.

Effect of arbuscular mycorrhizal fungi and Pseudomonas fluorescens on root-rot and wilt, growth and yield of Coleus forskohlii

Root-rot and wilt caused by Fusarium chlamydosporum affects the cultivation of Coleus forskohlii, a medicinal plant grown for its roots, which contain a pharmaceutically important compound called forskolin. In this study, management of this disease under low and high inoculum levels was assessed with four arbuscular mycorrhizal (AM) fungi and a strain of Pseudomonas fluorescens. The AM fungus Glomus fasciculatum and P. fluorescens were the most effective treatments that reduced the severity of root-rot and wilt of C. forskohlii by 56–65% and 61–66%, respectively, under lower and higher levels of pathogen F. chlamydosporum. G. fasciculatum increased the dry shoot and root weight by 108–241% and 92–204%, respectively, while in plants treated with P. fluorescens, an increase of 97–223% and 97–172% in dry shoot and root weight, respectively, was observed. Although P. fluorescens was effective, it gave higher root yields only under lower inoculum level of the pathogen. G. fasciculatum performed equally well under both lower and higher inoculum levels. Increase in yields with both the biocontrol agents was accompanied by increase in P uptake (230–303%) and in K uptake (270–335%). The forskolin content of the roots was significantly increased (14–21%) by G. fasciculatum, P. fluorescens or G. mosseae under lower inoculum level of pathogen.

Stimulatory effects of dual inoculation with phosphate solubilising microorganisms and arbuscular mycorrhizal fungus on chickpea

The stimulatory effect of rhizotrophic microorganisms on growth, yield and nutrient uptake of chickpea was determined in a pot experiment using sterilised soil deficient in available phosphorus (P). Plant vigour, yield and nutrient uptake were significantly enhanced following inoculation with Mesorhizobium ciceri and the phosphate solubilising bacterium Serratia (T1) or phosphate solubilising fungus Penicillium (WF6). Composite application of Mesorhizobium ciceri with Serratia and arbuscular mycorrhizal fungus Glomus fasciculatum had maximum positive effect on chickpea plants (0.68 and 2.21 g/plant at 50 and 90 days after sowing, respectively). Among all the treatments, the performance of M. ciceri with Serratia and G. fasciculatum and M. ciceri with Penicillium and G. fasciculatum was superior and increased the seed yield by 41 and 23%, respectively. The interactive effects were synergistically significant following inoculation of M. ciceri with Serratia and G. fasciculatum and Serratia with Penicillium and G. fasciculatum, which improved the photosynthetic pigment by 47 and 37%, respectively, relative to the control. Protein content in seeds varied between 18 and 24% in inoculated chickpea. Number of nodules formed per plant was higher at 90 days after sowing than 55 days after sowing. Phosphorus status of soil was improved by Serratia coinoculated with M. ciceri and G. fasciculatum but N content in general did not differ appreciably. At 90 days after sowing chickpea, there was an increase in (i) populations of phosphate solubilising microorganisms in some treatments, (ii) percentage root infection and (iii) spore density of the arbuscular mycorrhizal fungus in the soil.

GROWTH RESPONSE OF ACACIA PLANIFRONS W. et A. TO ARBUSCULAR MYCORRHIZAL FUNGI AND NITROGEN FIXING BACTERIA UNDER NURSERY CONDITIONS

ABSTRACT An experiment was conducted to determine the influence of arbuscular mycorrhizal (AM) fungi and Rhizobium sp. individually as well as in combinations, on the growth response of Acacia planifrons W. et A. seedlings in sterilized soil under greenhouse conditions. The native AM fungi Glomus fasciculatum (Thatcher) Gerd. & Trappe emend. Walker & Schenck & Smith emend. Koske and G. geosporum (Nicol & Gerd.) Walker were isolated from the rhizosphere of A. planifrons and multiplied in the roots of Zea mays (L.). The Rhizobium sp. was isolated from the root nodules of A. planifrons and cultured in yeast extract mannitol broth. These cultures were used to inoculate the seedlings of A. planifrons individually and in combinations. The results showed that co-inoculation of AM fungi and Rhizobium sp. increased the growth, biomass and nutrient uptake of A. planifrons more than single inoculations of AM fungi or Rhizobium sp. AM fungi and Rhizobium sp. inoculated seedlings had a higher accumulation of nitrogen (N), phosphorus (P) and potassium (K) than un-inoculated controls. The seedlings inoculated with triple root symbionts, G. fasciculatum + G. geosporum and Rhizobium sp. resulted in the maximum plant growth and nodular biomass production. Lower root to shoot ratios and increased seedling quality index were also obtained in these combinations.

EFFECT OF DUAL INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI AND BACTERIA ON GROWTH AND MINERAL NUTRITION OF STRAWBERRY

ABSTRACT Micropropagated plants of Fragaria x ananassa (cv. Senga sengana) were post-vitro inoculated in two experiments with the arbuscular mycorrhizal fungi Glomus fasciculatum, Glomus etunicatum and or Glomus claroideum and with bacterial isolates obtained from plant rhizosphere, from mycorrhizal mycelium and from root-free substrate. In the first experiment, the inoculation with the bacterial isolate M30 (from mycorrhizal mycelium) and with arbuscular mycorrhizal fungi G. fasciculatum and G. etunicatum significantly increased the plant growth. Bacteria frequently stimulated development of mycorrhiza, particularly the growth and dehydrogenase activity of extraradical mycorrhizal mycelium. In the second experiment, the isolate-specific effects of bacteria and mycorrhizal fungi were found at different doses of phosphorus (P) and nitrogen (N). The interaction between nutritional regime, bacteria and the fungi may be a determining factor of mycorrhizal symbiosis efficiency as regards possible benefits in stimulation of plant growth.

FIELD RESPONSE OF GARLIC INOCULATED WITH ARBUSCULAR MYCORRHIZAL FUNGI TO PHOSPHORUS FERTILIZATION

Several studies have demonstrated improved growth of plants infected with arbuscular mycorrhizal fungi (AMF) compared to non-AMF plants. The growth responses of garlic (Allium sativum" L.) to an AMF in soil fertilized with different levels of phosphorus (P) were studied under field conditions. Garlic cloves were planted in furrows after treatment with different P levels (0, 20, 40, and 60 Kg P ha−1), and with or without the AMF Glomus fasciculatum. Roots were sampled at three growth stages to quantify AMF. AMF colonization occurred at all samplings and the root colonization by AMF increased gradually with time, peaking at mid-bulb filling stage in the AMF-inoculated treatments. The AMF-inoculated plants had higher fresh bulb yield and mean bulb weight than uninoculated plants regardless of P level. This increase in yield and mean bulb weight was associated with a significant increase in the bulb P total accumulation of AMF inoculated plants. The enhancement in fresh bulb yield and mean bulb weight due to AMF-inoculation was highest in plots fertilized with 20 Kg P ha−1, whereas the AMF inoculation had no significant effect on these characters at higher P levels (40 and 60 Kg P ha−1). The AMF inoculant had no effect on bulb P concentration in plots fertilized with 60 Kg P ha−1, but increased the P total accumulation of garlic plants at all P levels. Results of this study indicate that garlic was dependent on mycorrhizae and responded to an AMF inoculant in soils containing intermediate levels of P. Therefore, AMF inoculants should be introduced into soil to ensure satisfactory garlic yields and reduced P fertilization.

Importance of root length in mycorrhizal colonization of welsh onion

Sixteen cultivars of Welsh onion (Allium fistulosum L.) with different root lengths were evaluated for phosphorus (P) uptake and response to arbuscular mycorrhizal inoculation. Allium fistulosum were grown with or without (control) arbuscular mycorrhizal fungus Glomus fasciculatum. Mycorrhizal colonization, root length, shoot dry weight and shoot P concentration were determined 82 d after sowing. All cultivars were highly colonized with G. fasciculatum. Shoot P uptake and shoot dry weight were different among cultivars and increased by the mycorrhizal colonization. Cultivars with short roots were more responsive to the mycorrhizal colonization than those with long roots. This suggests that root length should be considered in mycorrhizal‐plant symbiosis.

Dynamics of arbuscule development and degeneration in onion, bean, and tomato with reference to vesicular–arbuscular mycorrhizae in grasses

A quantitative light and electron microscopic study of developing and degenerating arbuscules of the vesicular–arbuscular mycorrhizal fungus Glomus fasciculatum in onion, bean, and tomato was carried out to estimate three parameters during the colonization cycle and to compare these parameters with those in maize, oats, and wheat. The parameters are (i) Vv(a,c) the fraction of the host cell volume (c) occupied by the arbuscule (a); (ii) VV(cy,c) the fraction of the host cell volume occupied by host cytoplasm (cy); and (iii) SV(p,c) the ratio of the surface area of the host protoplast (p) to the volume of the whole host cell. Uninfected cortical cells contained 3.4% cytoplasm in onion, 3.1% in bean, and 3.5% in tomato. In cells with mature arbuscules, cytoplasm increased to 9.9% in onion, 14.2% in bean, and 13.6% in tomato. Cells with mature arbuscules contained 11.4% fungus in onion, 20.3% in bean, and 20.5% in tomato. The initial SV(p,c) in onion was 0.10 μm2/μm3 and in bean and tomato 0.11 μm2/μm3. This increased to 0.37 μm2/μm3 in onion, 0.82 μm2/μm3 in bean, and 0.54 μm2/μm3 in tomato by the time arbuscules were mature. Development of the arbuscule was estimated to take 2.5 days and occupied 33% of the total cycle time. The variation seen across host species can be used as an indicator of fungal and (or) host control for each parameter. Arbuscular parameters of onion were compared with those obtained by other authors.