scholarly journals Colonization by arbuscular mycorrhizal and fine endophytic fungi in herbaceous vegetation in the Canadian High Arctic

2004 ◽  
Vol 82 (11) ◽  
pp. 1547-1556 ◽  
Author(s):  
Pål Axel Olsson ◽  
Bente Eriksen ◽  
Anders Dahlberg

The occurrence of arbuscular mycorrhizal (AM) fungi was surveyed along a latitudinal gradient in Arctic Canada including Banks Island (73°N), Devon Island (74°N), Ellesmere Island (76°N), and the Magnetic North Pole at Ellef Ringnes Island (78°N). At Banks Island, AM fungi were present and colonized at a high intensity in all specimens of Potentilla hookeriana Lehm. – Potentilla pulchella R.Br., Arnica angustifolia Vahl, and Erigeron uniflorus L. ssp. eriocephalus (Vahl ex Hornen.) Cronq. sampled. The soil collected under these plants showed a high inoculum potential when tested at greenhouse conditions using Plantago lanceolata L. as a bait plant. Occasional occurrence of AM fungi was recorded in Festuca hyperborea Holmen ex Frederiksen, Trisetum spicatum (L.) Richt., and Potentilla hookeriana – Potentilla pulchella at Devon Island. Despite the fact that potential AM plants are present, no AM was found at the two most northern sites, Ellesmere Island and Ellef Ringnes Island. There seems to be climatic or dispersal limitations to AM colonization at these northern sites. Fine endophytic fungi, formerly named Glomus tenue (Grenall) I.R. Hall, were recorded at all four sites, but most frequently at Banks Island. We thereby provide further evidence that fine endophytes are more frequent in harsh climatic conditions than AM fungi. There was a relatively high proportion of nonmycorrhizal plant species at all sites, and this proportion increased towards the north.Key words: arctic, arbuscular mycorrhiza, fine endophytes, dark septate fungi.

HortScience ◽  
2002 ◽  
Vol 37 (5) ◽  
pp. 778-782 ◽  
Author(s):  
W.E. Klingeman ◽  
R.M. Augé ◽  
P.C. Flanagan

Mycorrhizal symbiosis, a natural association between roots and certain soil fungi, can improve growth and increase stress resistance of many nursery crops. Field soils of four middle Tennessee and two eastern Tennessee nurseries were surveyed for their mycorrhizal inoculum potential (MIP), phosphorus (P) and potassium (K) concentrations, and soil pH. Arbuscular mycorrhizal (AM) fungi, which colonized seedlings of a Sorghum bicolor trap-crop, were recovered from all soils. Tissue samples were taken from young roots of three economically important tree species grown in nursery field soils: red maple (Acer rubrum L. `October Glory'), flowering dogwood (Cornus florida L. `Cherokee Princess'), and Kwanzan cherry (Prunus serrulata Lindl. `Kwanzan'). AM fungi, regardless of soil type, soil pH, or P or K concentration, had colonized young roots of all three species. Unless interested in establishing exotic mycorrhizae, ornamental nursery producers in Tennessee do not need to supplement field soils with these beneficial fungi.


2000 ◽  
Vol 16 (4) ◽  
pp. 603-622 ◽  
Author(s):  
W. Zangaro ◽  
V. L. R. Bononi ◽  
S. B. Trufen

Seedlings from 43 native woody species belonging to different successional groups from the Tibagi River Basin, Paraná State, South Brazil were studied to obtain information on the importance of colonization by native arbuscular mycorrhizal (AM) fungi. The experiment was carried out in a greenhouse for 15 to 45 wk, with soil-mix treatments and four successional groups. The mycorrhizal dependency was 90, 48, 12 and 14% of the pioneer, early secondary, late secondary and climax species, respectively. The content of P, Ca and K was 20, 17 and 23 times greater, respectively, in the leaves of the pioneer species than in the other successional groups. The colonization by AM fungi in field was studied in seedlings of 36 native woody species collected in the interior of the forest of the Mata dos Godoy State Park, and in open area at the beginning of arboreal succession. The mycorrhizal colonization in the field was 55.5, 26.9, 6.1 and 2.2% for the pioneer, early secondary, late secondary and climax species, respectively. To assess the mycorrhizal inoculum potential, rhizosphere soil was collected in the interior of the forest and a gap in the same forest and in a cleared area abandoned for natural regeneration. The inoculum potentials and the spore number in the area at the beginning of succession were 5.6 and 53.4 times greater than in the interior of the forest. The results show that the initial growth of the woody species which take part in the initial phases of succession may be more dependent on the AM fungi, in soils poor in minerals, while those that make up the final succession phases may be less dependent. The potential of the AM fungi inoculum decreases throughout the successional process and there is a relation between the inoculum potential found in the field and the occurrence for the different habitats of the species of adult plants belonging to different successional groups.


2012 ◽  
Vol 28 (5) ◽  
pp. 453-462 ◽  
Author(s):  
Waldemar Zangaro ◽  
Adrielly Pereira Ansanelo ◽  
Luis Eduardo Azevedo Marques Lescano ◽  
Ricardo de Almeida Alves ◽  
Artur Berbel Lírio Rondina ◽  
...  

Abstract:Little is known about the relationship involving arbuscular mycorrhizal (AM) fungi and functional groups of plants that characterize different phases of tropical succession. We appraised the AM infection intensity of root cortex and spore density in the soil in sites over tropical successional gradients (grassland, secondary forest and mature forest) for several years in Araucaria, Atlantic and Pantanal ecosystems in Brazil. The intensity of AM infection decreased with advancing successional stages in all ecosystems and it was around 60–80% in early stages of succession, 37–56% in secondary forests and 19–29% in mature forests. Similarly, the AM spore number also decreased with advancing succession and was the highest in early stages (73–123 g−1), intermediate in secondary forests (32–54 g−1) and lowest in the mature forests (10–23 g−1). To verify whether such reductions influenced the potential of AM inoculum in soil, seedlings of Heliocarpus popayanensis (Malvaceae) were grown as test plants in soils obtained from five grasslands, five young secondary forests, and five mature forests in the Atlantic ecosystem. The soil inocula from the grasslands and secondary forests were 7.6 and 5.7 times more effective in stimulating seedling growth than inocula from the mature forests, respectively. Our results show that plant species in grasslands and young secondary forests stimulate the multiplication of AM fungi, leading to a higher potential of the AM inoculum. In later-successional stages, plant investment in AM fungi decreases and the potential of the AM inoculum is also reduced.


2012 ◽  
Vol 71 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Thangavelu Muthukumar ◽  
Kandasamy Prabha

Fungal associations in gametophytes and young sporophytic roots of the fernNephrolepis exaltataInformation is limited on the presence of endophytic fungal associations in green gametophytes and young sporophytes of extant ferns. Nothing is known about their presence in Polypodiales, the largest order among extant ferns. We screened chlorophyllous gametophytes and young sporophytes ofNephrolepis exaltata(L.) Schott., (Lomariopsidaceae, Polypodiales) growing naturally on soil, brick and coir for the presence of fungal endophytes. Gametophytes and young sporophytes growing on different substrates were invariably colonized by septate endophytic fungi. Hyaline or brown, regularly septate, inter- or intracellular hyphae with moniliform cells or microsclerotia characterized septate endophytic fungi. However, only the roots of young sporophytes growing on soil and bricks harboured arbuscular mycorrhizal (AM) fungi. The AM morphology conformed to the intermediate type with intracellular hyphal coils, arbusculate coils and intercellular hyphae. No AM fungal spores could be retrieved from the soil on which gametophytes and young sporophytes were growing. The observations in this study support the idea that the septate fungal endophytes could confer an ecological advantage on colonized individuals, especially on nutrient deficient substrates.


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 583
Author(s):  
Reda E. Abdelhameed ◽  
Nagwa I. Abu-Elsaad ◽  
Arafat Abdel Hamed Abdel Latef ◽  
Rabab A. Metwally

Important gaps in knowledge remain regarding the potential of nanoparticles (NPs) for plants, particularly the existence of helpful microorganisms, for instance, arbuscular mycorrhizal (AM) fungi present in the soil. Hence, more profound studies are required to distinguish the impact of NPs on plant growth inoculated with AM fungi and their role in NP uptake to develop smart nanotechnology implementations in crop improvement. Zinc ferrite (ZnFe2O4) NPs are prepared via the citrate technique and defined by X-ray diffraction (XRD) as well as transmission electron microscopy for several physical properties. The analysis of the XRD pattern confirmed the creation of a nanocrystalline structure with a crystallite size equal to 25.4 nm. The effects of ZnFe2O4 NP on AM fungi, growth and pigment content as well as nutrient uptake of pea (Pisum sativum) plants were assessed. ZnFe2O4 NP application caused a slight decrease in root colonization. However, its application showed an augmentation of 74.36% and 91.89% in AM pea plant shoots and roots’ fresh weights, respectively, compared to the control. Moreover, the synthesized ZnFe2O4 NP uptake by plant roots and their contents were enhanced by AM fungi. These findings suggest the safe use of ZnFe2O4 NPs in nano-agricultural applications for plant development with AM fungi.


Author(s):  
Yinli Bi ◽  
Linlin Xie ◽  
Zhigang Wang ◽  
Kun Wang ◽  
Wenwen Liu ◽  
...  

AbstractArbuscular mycorrhizal (AM) fungi can successfully enhance photosynthesis (Pn) and plants growth in agricultural or grassland ecosystems. However, how the symbionts affect species restoration in sunlight-intensive areas remains largely unexplored. Therefore, this study’s objective was to assess the effect of AM fungi on apricot seedling physiology, within a specific time period, in northwest China. In 2010, an experimental field was established in Shaanxi Province, northwest China. The experimental treatments included two AM fungi inoculation levels (0 or 100 g of AM fungal inoculum per seedling), three shade levels (1900, 1100, and 550 µmol m−2 s−1), and three ages (1, 3, and 5 years) of transplantation. We examined growth, Pn, and morphological indicators of apricot (Prunus sibirica L.) seedling performances in 2011, 2013, and 2015. The colonization rate in mycorrhizal seedlings with similar amounts of shade is higher than the corresponding controls. The mycorrhizal seedling biomass is significantly higher than the corresponding non-mycorrhizal seedling biomass. Generally, Pn, stomatal conductance (Gs), transpiration rate (Tr), and water use efficiency are also significantly higher in the mycorrhizal seedlings. Moreover, mycorrhizal seedlings with light shade (LS) have the highest Pn. WUE is increased in non-mycorrhizal seedlings because of the reduction in Tr, while Tr is increased in mycorrhizal seedlings with shade. There is a significant increase in the N, P, and K fractions detected in roots compared with shoots. This means that LS had apparent benefits for mycorrhizal seedlings. Our results also indicate that AM fungi, combined with LS, exert a positive effect on apricot behavior.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Crosino ◽  
Elisa Moscato ◽  
Marco Blangetti ◽  
Gennaro Carotenuto ◽  
Federica Spina ◽  
...  

AbstractShort chain chitooligosaccharides (COs) are chitin derivative molecules involved in plant-fungus signaling during arbuscular mycorrhizal (AM) interactions. In host plants, COs activate a symbiotic signalling pathway that regulates AM-related gene expression. Furthermore, exogenous CO application was shown to promote AM establishment, with a major interest for agricultural applications of AM fungi as biofertilizers. Currently, the main source of commercial COs is from the shrimp processing industry, but purification costs and environmental concerns limit the convenience of this approach. In an attempt to find a low cost and low impact alternative, this work aimed to isolate, characterize and test the bioactivity of COs from selected strains of phylogenetically distant filamentous fungi: Pleurotus ostreatus, Cunninghamella bertholletiae and Trichoderma viride. Our optimized protocol successfully isolated short chain COs from lyophilized fungal biomass. Fungal COs were more acetylated and displayed a higher biological activity compared to shrimp-derived COs, a feature that—alongside low production costs—opens promising perspectives for the large scale use of COs in agriculture.


2021 ◽  
Vol 9 (2) ◽  
pp. 229
Author(s):  
Martti Vasar ◽  
John Davison ◽  
Siim-Kaarel Sepp ◽  
Maarja Öpik ◽  
Mari Moora ◽  
...  

Deserts cover a significant proportion of the Earth’s surface and continue to expand as a consequence of climate change. Mutualistic arbuscular mycorrhizal (AM) fungi are functionally important plant root symbionts, and may be particularly important in drought stressed systems such as deserts. Here we provide a first molecular characterization of the AM fungi occurring in several desert ecosystems worldwide. We sequenced AM fungal DNA from soil samples collected from deserts in six different regions of the globe using the primer pair WANDA-AML2 with Illumina MiSeq. We recorded altogether 50 AM fungal phylotypes. Glomeraceae was the most common family, while Claroideoglomeraceae, Diversisporaceae and Acaulosporaceae were represented with lower frequency and abundance. The most diverse site, with 35 virtual taxa (VT), was in the Israeli Negev desert. Sites representing harsh conditions yielded relatively few reads and low richness estimates, for example, a Saudi Arabian desert site where only three Diversispora VT were recorded. The AM fungal taxa recorded in the desert soils are mostly geographically and ecologically widespread. However, in four sites out of six, communities comprised more desert-affiliated taxa (according to the MaarjAM database) than expected at random. AM fungal VT present in samples were phylogenetically clustered compared with the global taxon pool, suggesting that nonrandom assembly processes, notably habitat filtering, may have shaped desert fungal assemblages.


2021 ◽  
Vol 22 (2) ◽  
pp. 711
Author(s):  
Irina V. Leppyanen ◽  
Olga A. Pavlova ◽  
Maria A. Vashurina ◽  
Andrey D. Bovin ◽  
Alexandra V. Dolgikh ◽  
...  

This study focused on the interactions of pea (Pisum sativum L.) plants with phytopathogenic and beneficial fungi. Here, we examined whether the lysin-motif (LysM) receptor-like kinase PsLYK9 is directly involved in the perception of long- and short-chain chitooligosaccharides (COs) released after hydrolysis of the cell walls of phytopathogenic fungi and identified in arbuscular mycorrhizal (AM) fungal exudates. The identification and analysis of pea mutants impaired in the lyk9 gene confirmed the involvement of PsLYK9 in symbiosis development with AM fungi. Additionally, PsLYK9 regulated the immune response and resistance to phytopathogenic fungi, suggesting its bifunctional role. The existence of co-receptors may provide explanations for the potential dual role of PsLYK9 in the regulation of interactions with pathogenic and AM fungi. Co-immunoprecipitation assay revealed that PsLYK9 and two proposed co-receptors, PsLYR4 and PsLYR3, can form complexes. Analysis of binding capacity showed that PsLYK9 and PsLYR4, synthesized as extracellular domains in insect cells, were able to bind the deacetylated (DA) oligomers CO5-DA–CO8-DA. Our results suggest that the receptor complex consisting of PsLYK9 and PsLYR4 can trigger a signal pathway that stimulates the immune response in peas. However, PsLYR3 seems not to be involved in the perception of CO4-5, as a possible co-receptor of PsLYK9.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoj-Kumar Arthikala ◽  
Kalpana Nanjareddy ◽  
Lourdes Blanco ◽  
Xóchitl Alvarado-Affantranger ◽  
Miguel Lara

AbstractTarget of rapamycin (TOR) is a conserved central growth regulator in eukaryotes that has a key role in maintaining cellular nutrient and energy status. Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts that assist the plant in increasing nutrient absorption from the rhizosphere. However, the role of legume TOR in AM fungal symbiosis development has not been investigated. In this study, we examined the function of legume TOR in the development and formation of AM fungal symbiosis. RNA-interference-mediated knockdown of TOR transcripts in common bean (Phaseolus vulgaris) hairy roots notably suppressed AM fungus-induced lateral root formation by altering the expression of root meristem regulatory genes, i.e., UPB1, RGFs, and sulfur assimilation and S-phase genes. Mycorrhized PvTOR-knockdown roots had significantly more extraradical hyphae and hyphopodia than the control (empty vector) roots. Strong promoter activity of PvTOR was observed at the site of hyphal penetration and colonization. Colonization along the root length was affected in mycorrhized PvTOR-knockdown roots and the arbuscules were stunted. Furthermore, the expression of genes induced by AM symbiosis such as SWEET1, VPY, VAMP713, and STR was repressed under mycorrhized conditions in PvTOR-knockdown roots. Based on these observations, we conclude that PvTOR is a key player in regulating arbuscule development during AM symbiosis in P. vulgaris. These results provide insight into legume TOR as a potential regulatory factor influencing the symbiotic associations of P. vulgaris and other legumes.


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