Soil moisture—a regulator of arbuscular mycorrhizal fungal community assembly and symbiotic phosphorus uptake (original) (raw)
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In modern agriculture, reducing fertilizers are the main objectives. Maize plant is an effective host of mycorrhiza in infertile conditions. In order to study effects of arbuscular mycorrhizal fungi (AMF) on phosphorus concentration (PC) and root colonization (RC) in maize (Zea mays L.), two field experiments were conducted in 2011 and 2012 (June 7 th ). The experiments were carried out split-plot factorial design based on randomized complete block design with three replications. Irrigation as the main plot was exerted in three levels; based on 70, 50 and 30% field capacity respectively. Mycorrhizal biofertilizer as the sub plot was applied in two levels; control and mycorrhizal biofertilizer application (100 kg ha -1 ). Phosphorus fertilizer as the sub plot was applied in three levels; 0, 75 and 150 kg ha -1 triple superphosphate respectively. The results of combined analysis showed that different irrigation treatments have significantly affected PC. The measured traits as affected by different irrigation regimes were decreased by increasing drought stress. Different P fertilizer levels and mycorrhizal biofertilizer have significantly affected PC and RC. Leaf P concentration and root colonization were increased and decreased by increasing P application respectively. AM plants have increased about 12% P concentration to their leaves compared with non-mycorrhizal.
2021
Studies have shown arbuscular mycorrhizal fungi (AMF) enhance phosphorus (P) uptake and drought tolerance in maize (Zea mays L.) grown in semiarid soils. However, little is known regarding the contribution of AMF to maize treated with different levels of phosphorus and grown in different soil moisture levels. This study was conducted to determine the effects of AMF (Glomus fasciculatum) inoculation on growth and P uptake of maize treated with different levels of soil P and soil moisture. Different P levels (0, 50, and 100 kg P ha-1) were applied on maize grown in soils with and without mycorrhizal fungi, and at different moisture levels producing -0.05, -0.4, -0.8, and -1.5 MPa of drought stress. Increasing P rates significantly (p < 0.05) reduced mycorrhizal colonization. Mycorrhizal colonization was higher under moderate than under lower soil moisture levels. Drought stress × soil P content × AMF inoculation interaction had significant (p < 0.05) effect on maize shoot and ro...
Indian Journal of Microbiology
The presence of arbuscular mycorrhizas in fens has received little attention, but because fen plants are often phosphorus limited, the plant-fungus interaction could be an important factor in plant competition for phosphorus. In this field study, we determined mycorrhizal colonization rates for 18 fen plant species. Also in the field, we examined the effect of four different forms of phosphorus on the percentage colonization for one fen plant species, Solidago patula. We found that in a species-rich, phosphorus-poor wetland both mycorrhizal and nonmycorrhizal species were common. Nine of ten dicotyledonous species examined formed arbuscular mycorrhizas, while all monocotyledonous species were at most very weakly mycorrhizal. A morphological explanation for this pattern is that the monocots in our study have more extensive aerenchyma, especially in coarse roots. Therefore, monocots are able to transport oxygen to their roots more effectively than dicots. In the organic wetland soil, additional oxygen in the rhizosphere promotes phosphorus mineralization and availability. Two of the monocot species (Typha latifolia and Carex lasiocarpa), which have been described previously as mycorrhizal in other wetland types, are surprisingly nonmycorrhizal in our phosphorus-poor study site, suggesting that a mycorrhizal association would not offer improved phosphorus nutrition to these species. In contrast, our field phosphorus addition decreased mycorrhizal colonization in S. patula, suggesting that one benefit to S. patula of the mycorrhizas is phosphorus uptake.
Mycorrhiza, 2015
Field studies have revealed the impact of changing water regimes on the structure of arbuscular mycorrhizal fungal (AMF) communities, but it is not known what happens to the abundance of individual AMF species within the community when the water conditions in the rhizosphere change. The behavior of four AMF species isolated from the Arabian desert (Diversispora aurantia, Diversispora omaniana, Septoglomus africanum, and an undescribed Paraglomus species) was investigated when assembled in microcosms containing Sorghum bicolor as host plant, and treated with various water regimes. Furthermore, the impact of invasion of these assemblages by Rhizophagus irregularis, an AMF species widely used in commercial inocula, was studied. The abundance of each AMF species in sorghum roots was measured by determining the transcript numbers of their large ribosomal subunit (rLSU) by real-time PCR, using cDNA and species-specific primers. Plant biomass and length of AMF extraradical hyphae were also...
Frontiers in Plant Science, 2024
Arbuscular mycorrhizal fungi (AMF) are ancient and ecologically important symbionts that colonize plant roots. These symbionts assist in the uptake of water and nutrients, particularly phosphorus, from the soil. This important role has led to the development of AMF inoculants for use as biofertilizers in agriculture. Commercial mycorrhizal inoculants are increasingly popular to produce onion and carrot, but their specific effects on native mycorrhizal communities under field conditions are not known. Furthermore, adequate availability of nutrients in soils, specifically phosphorus, can reduce the diversity and abundance of AMF communities in the roots. The type of crop grown can also influence the composition of AMF communities colonizing the plant roots. This study aimed to investigate how AMF inoculants, soil phosphorus levels, and plant species influence the diversity of AMF communities that colonize the roots of onion and carrot plants. Field trials were conducted on high organic matter (muck) soil in the Holland Marsh, Ontario, Canada. The treatments included AMF-coated seeds (three to five propagules of Rhizophagus irregularis per seed) and non-treated onion and carrot seeds grown in soil with low (~46 ppm) and high (~78 ppm) phosphorus levels. The mycorrhizal communities colonizing the onion and carrot roots were identified by Illumina sequencing. Five genera, Diversispora, Claroideoglomus, Funneliformis, Rhizophagus, and Glomus, were identified in roots of both plant species. AMF communities colonizing carrot roots were more diverse and richer than those colonizing onion roots. Diversispora and Funneliformis had a 1.3-fold and 2.9-fold greater abundance, respectively, in onion roots compared to carrots. Claroideoglomus was 1.4-fold more abundant in carrot roots than in onions. Inoculation with R. irregularis increased the abundance and richness of Rhizophagus in AMF communities of onion roots but not in carrot roots. The soil phosphorus level had no effect on the richness and diversity of AMF in the roots of either crop. In summary, AMF inoculant and soil phosphorus levels influenced the composition of AMF communities colonizing the roots of onion and carrot plants, but the effects varied between plant species.
Correlation between arbuscular mycorrhiza in wheat and physicochemical characteristics of soil
Plant Pathology Science
Introduction: Arbuscular mycorrhizal fungi (AMF) in symbiosis with plant roots help to absorb more phosphorus, and increase the growth and development of plants. The aim of this study was to determine the correlation between population and diversity of AMF, and physicochemical characteristics of soil in wheat fields of Kohgiluyeh and Boyer-Ahmad province in southwestern Iran. Materials and Methods: Thirty wheat fields in this province, were visited near harvest time, and their rhizosphere and aerial organs were sampled. AMF spores were isolated by sieving the rhizosphere suspension in water and centrifuging in Sucrose solution. The spore population of these fungi was count. The percentage of root length colonization by these fungi was calculated in every sample. The morphological characteristics of the isolated spores were studied and the collected information was compared with the descriptions of AMF and the fungi present in each sample were identified. Texture, soil dispersion, soil and plant phosphorus content were determined and the correlation coefficient between AMF population and diversity with physical and chemical characteristics of soil and wheat plant were calculated. Results: Fifteen arbuscular mycorrhizal fungi belonging to nine genera: Acaulospora, Archaeospora, Entrophospora, Gigaspora, Claroideumglomus, Funeliformis, Rhizoglomus, Septoglomus and Scutellospora were identified. The diversity of these fungi in the samples was (2-)2.9(-5) and F. mosseae was dominant species with 90% relative frequency. The population of these fungi had a negative correlation with soil pH, but with soil soluble phosphorus and plant phosphorus content had a positive correlation. The diversity of these fungi had a positive correlation with soil soluble phosphorus. There was a positive correlation between the amount of sand in the soil and the root length colonization. Conclusion: AMF have a greater population and diversity in soils with light texture, less moisture along with low amounts of soluble phosphorus and organic matter. The positive correlation between the population of these fungi and plant phosphorus indicates their usefulness for the plant.
Plant and Soil, 2011
To investigate whether arbuscular mycorrhizal fungi (AMF)abundant in a phosphatepolluted but nitrogen-poor field siteimprove plant N nutrition, we carried out a two-factorial experiment, including N fertilization and fungicide treatment. Percentage of root length colonized (% RLC) by AMF and tissue element concentrations were determined for four resident plant species. Furthermore, soil nutrient levels and N effects on aboveground biomass of individual species were measured. Nitrogen fertilization lowered % RLC by AMF of Artemisia vulgaris L., Poa compressa L., but not of Bromus japonicus Thunb. Thistogether with positive N addition effects on N status, N:P-ratio and aboveground biomass of most speciessuggested that plants are mycorrhizal because of N deficiency. Fungicide treatment, which reduced % RLC in all species, resulted in lower N concentrations in A. vulgaris and P. hieracioides, a higher N concentration in P. compressa, and did not consistently affect N status of B. japonicus. Evidently, AMF had an influence on the N nutrition of plants in this P-rich soil; howeverpotentially due to differences in their mycorrhizal responsivenessnot all species seemed to benefit from a mycorrhiza-mediated N uptake and accordingly, N distribution.
Interaction between root growth allocation and mycorrhizal fungi in soil with patchy P distribution
Plant and Soil, 2013
Aims and Background Many plants preferentially grow roots into P-enriched soil patches, but little is known about how the presence of arbuscular mycorrhizal fungi (AMF) affects this response. Methods Lotus japonicus (L.) was grown in a low-P soil with (a) no additional P, (b) homogeneous P (28 mg pot −1 ), (c) low heterogeneous P (9.3 mg pot −1 ), and (d) high heterogeneous P (28 mg pot −1 ). Each P treatment was combined with one of three mycorrhiza treatments: no mycorrhizae, Glomus intraradices, indigenous AMF. Real-time PCR was used to assess the abundance of G. intraradices and the indigeneous AMF G. mosseae and G. claroideum. Results Mycorrhization and P fertilization strongly increased plant growth. Homogeneous P supply enhanced growth in both mycorrhizal treatments, while heterogeneous P fertilization increased biomass production only in treatments with indigenous AMF inoculation. Preferential root allocation into P-enriched soil was significant only in absence of AMF. The abundance of AMF species was similar in P-enriched and unfertilized soil patches.
In Vivo Modulation of Arbuscular Mycorrhizal Symbiosis and Soil Quality by Fungal P Solubilizers
Microbial Ecology, 2019
Phosphorus (P) is an essential nutrient with low bioavailability in soils for plant growth. The use of P solubilization fungi (PSF) has arisen as an eco-friendly strategy to increase this nutrient's bioavailability. The effect of PSF inoculation and its combination with P-transporting organisms (arbuscular mycorrhizal fungi, AMF) on plant growth has been previously studied. However, these studies did not evaluate the combined effect of PSF and AMF inoculation on plant growth, symbiosis, and soil quality. Therefore, the aim of this study is to assess the impact of PSF on the AMF-wheat symbiosis establishment and efficiency, considering the effect on plant growth and soil quality. We performed a greenhouse experiment with wheat under different treatments (+/−AMF: Rhizophagus irregularis; +/−PSF strains: Talaromyces flavus, T. helicus L7B, T. helicus N24, and T. diversus) and measured plant growth, AMF root colonization, symbiotic efficiency, and soil quality indicators. No interaction between PSF and R. irregularis was found in wheat growth, showcasing that their combination is not better than single inoculation. T. helicus strains did not interfere with the AMF-wheat symbiosis establishment, while T. diversus and T. flavus decreased it. The symbiotic efficiency was increased by T. flavus and T. helicus N24, and unchanged with T. helicus L7B and T. diversus inoculation. The soil quality indicators were higher with microbial co-inoculation, particularly the alkaline phosphatases parameter, showing the beneficial role of fungi in soil. This work highlights the importance of microbial interactions in the rhizosphere for crop sustainability and soil quality improvement, assessing the effects of PSF on AMF-wheat symbiosis.
2016
In most tropical soils, phosphorus is deficient and high costs of phosphorus fertilizer made it difficult for smallholder farmers to use it when needed. Arbuscular mycorrhizal fungi is known to improve particularly P in P deficient soils. However, response of plant species to mycorrhizal fungi inoculation and application of different rates of P varies. Therefore, this study was conducted to investigate the effect of phosphorus (P) concentrations on arbuscular mycorrhizal fungi (AMF) colonization and growth of two perennial crops (Catha edulis and Ensete ventricosum) and four multipurpose agroforestry trees (Cordia africana, Croton macrostachyus, Erythrina brucei and Millettia ferruginea). The experiment was conducted in a glasshouse. The treatment consisted of 0, 0.005, 0.01, 0.02, 0.05, and 0.1 mg P/g substrate and three species of AMF. The experiment was laid out in CRD design in a factorial arrangement. The results showed that plant growth parameters (shoot length and dry weight)...