scholarly journals Exogenous arbuscular mycorrhizal fungi increase soil organic carbon and change microbial community in poplar rhizosphere

2019 ◽  
Vol 65 (No. 3) ◽  
pp. 152-158 ◽  
Author(s):  
Haoqiang Zhang ◽  
Ting Liu ◽  
Yuanyuan Wang ◽  
Ming Tang

Arbuscular mycorrhizal fungi (AMF) increase soil organic carbon (SOC) deposition via secretion of glomalin-related soil protein (GRSP) and modulation of plant carbon partition. Two exogenous AMF inocula (Rhizophagus irregularis and Glomus versiforme) were applied to the roots of Populus × canadensis seedlings grown in the unsterilized nursery soil. The diversity of fungal and bacterial communities was assessed by the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method, while the accumulation of GRSP and SOC content in 22.5 cm-deep soil was measured. The results indicated that two AMF additions increased root colonization frequency as well as poplar biomass, especially root biomass accumulation. Two AMF applications improved the easily extractable-GRSP, total-GRSP, and SOC accumulation in the rhizosphere of poplar seedlings, limited the fungal community, and exerted no influence on the bacterial community. The effect of G. versiforme on GRSP and SOC accumulation was higher than that of R. irregularis. The AMF introduced GRSP, and SOC accumulation was highly correlated the limited fungal species richness.

2004 ◽  
Vol 70 (3) ◽  
pp. 1413-1424 ◽  
Author(s):  
Francisco A. de Souza ◽  
George A. Kowalchuk ◽  
Paula Leeflang ◽  
Johannes A. van Veen ◽  
Eric Smit

ABSTRACT Despite the importance of arbuscular mycorrhizal fungi in the majority of terrestrial ecosystems, their ecology, genetics, and evolution are poorly understood, partly due to difficulties associated with detecting and identifying species. We explored the inter- and intraspecies variations of the 18S rRNA genes of the genus Gigaspora to assess the use of this marker for the discrimination of Gigaspora isolates and of Gigasporaceae populations from environmental samples. Screening of 48 Gigaspora isolates by PCR-denaturing gradient gel electrophoresis (DGGE) revealed that the V3-V4 region of the 18S rRNA gene contained insufficient variation to discriminate between different Gigaspora species. In contrast, the patterns of 18S ribosomal DNA (rDNA) heterogeneity within the V9 region of this marker could be used for reliable identification of all recognized species within this genus. PCR-DGGE patterns provided insight into some putative misidentifications and could be used to differentiate geographic isolates of G. albida, G. gigantea, and G. margarita but not G. rosea. Two major clusters were apparent based upon PCR-DGGE ribotype patterns, one containing G. albida, G. candida, G. ramisporophora, and G. rosea and the other containing G. decipiens and G. margarita. Dissection of the DGGE patterns by cloning, DGGE screening, and sequencing confirmed these groupings and revealed that some ribotypes were shared across species boundaries. Of the 48 isolates examined, only two displayed any spore-to-spore variation, and these exceptions may be indicative of coisolation of more than one species or subspecies within these cultures. Two Brazilian agricultural soils were also analyzed with a Gigasporaceae-specific nested PCR approach, revealing a dominance of G. margarita within this family.


2012 ◽  
Vol 14 (4) ◽  
pp. 692-699 ◽  
Author(s):  
M.C. Arango ◽  
M.F. Ruscitti ◽  
M.G. Ronco ◽  
J. Beltrano

This study evaluated the effects of inoculation with the arbuscular mycorrhizal fungi Glomus mosseae, Glomus intraradices A4 and Glomus intraradices B1 and two phosphorus levels (10 and 40 mg kg-1) on root colonization, plant growth, nutrient uptake and essential oil content in Mentha piperita L. The experiment was carried out in a greenhouse, in 4x2 factorial arrangement, in completely randomized design. At sixty days after transplanting, the mycorrhizal plants had significantly higher fresh matter, dry matter and leaf area compared to non-mycorrhizal plants. The inoculation increased P, K and Ca levels in the shoot which were higher under 40 mg P kg-1 of soil. Plants grown with 40 mg P kg-1 soil increased the essential oil yield per plant by about 40-50% compared to those cultivated with 10 mg P kg-1, regardless of the mycorrhizal treatment. Among the studied fungal species, inoculation with G. intraradices A4 and a high level of P significantly increased plant growth and essential oil yield, compared to the other studied mycorrhizal fungal species. In conclusion, inoculation of arbuscular mycorrhizal fungi into peppermint plants is a feasible alternative to increase the essential oil production and reduce the use of fertilizers required to obtain economic production of peppermint under phosphorus-deficient soil condition.


2014 ◽  
Vol 37 (1-2) ◽  
pp. 39-62 ◽  
Author(s):  
Janusz Błaszkowski ◽  
Iwona Adamska ◽  
Beata Czerniawska

The occurrence of arbuscular mycorrhizal fungi (AMF) of the, phylum <i>Glomeromycota</i> associated with plants of maritime sand dunes of the Vistula Bar localed in north-eastern Poland was investigated. The presence of AMF was revealed based on spores isolated from field-collected root-rhizosphere soil mixtures and two-cycle pot trap cultures established with parts of these mixtures. The mixtures came from under five species in four plant families. Spores of AMF occurred in 54.8% of the field samples and belonged to eight species. Additionally, culturing of root-soil mixtures in trap cultures revealed nine species and three undescribed morphotypes carlier not found in the field samples. Considering the number of records of species and morphotypes in the field samples and trap cultures, the fungal species most frequently occurring in dunes of the Vistula Bar is <i>Scutellospora dipurpurescens</i>, followed by <i>Archaeospora trappei, Glomus laccatum</i>, and <i>Scu. armeniaca</i>. The overall average spore abundance in the field samples is low (4.48, range O-3l in 100g dry soil). The ovcrall average species richness determined based on spores from both the field and trap cultures was 2 l and ranged from 0 lo 7 in 100g dry soil. The plant harbouring the highest number of species of AMF was <i>Festuca rubra</i>. Of the maritime dune sites of Poland examined to date, the species composition of AMF of the Vistula Bar is most similar to that of the Słowiński National Park. When the comparisons included 15 maritime dune areas located outside Poland, the highest similarity occurred in the Vistula Bar/Canada comparison.


2001 ◽  
Vol 79 (10) ◽  
pp. 1161-1166 ◽  
Author(s):  
John N Klironomos ◽  
Miranda M Hart ◽  
Jane E Gurney ◽  
Peter Moutoglis

Arbuscular mycorrhizal fungal communities in northern temperate ecosystems must function during extremes in environmental conditions. However, it is not known if arbuscular mycorrhizal fungi that co-exist in soil communities have similar tolerances to stresses such as drought and freezing. The phenology of arbuscular mycorrhizal fungi was determined over one year in a community in southern Ontario, Canada. Five fungal species from the same community were then used to inoculate five plant species, in all possible combinations, and were subjected to either a freezing treatment or a drought treatment after which new seedlings were transplanted into the treated pots. The percent colonization of roots of each plant species was measured as the difference in mean colonization from the control. Freezing reduced percent colonization in almost every case, whereas drought resulted in both increased and decreased percent colonization. Fungal species responded differently to the treatments, and there was a pronounced plant × fungus effect. These results support the hypothesis that distinct functional groups of arbuscular mycorrhizal fungi exist, and these may determine plant community structure.Key words: arbuscular mycorrhizal fungi, freezing, drying, functional diversity.


2005 ◽  
Vol 71 (11) ◽  
pp. 6673-6679 ◽  
Author(s):  
David Roesti ◽  
Kurt Ineichen ◽  
Olivier Braissant ◽  
Dirk Redecker ◽  
Andres Wiemken ◽  
...  

ABSTRACT Spores of the arbuscular mycorrhizal fungi (AMF) Glomus geosporum and Glomus constrictum were harvested from single-spore-derived pot cultures with either Plantago lanceolata or Hieracium pilosella as host plants. PCR-denaturing gradient gel electrophoresis analysis revealed that the bacterial communities associated with the spores depended more on AMF than host plant identity. The composition of the bacterial populations linked to the spores could be predominantly influenced by a specific spore wall composition or AMF exudate rather than by specific root exudates. The majority of the bacterial sequences that were common to both G. geosporum and G. constrictum spores were affiliated with taxonomic groups known to degrade biopolymers (Cellvibrio, Chondromyces, Flexibacter, Lysobacter, and Pseudomonas). Scanning electron microscopy of G. geosporum spores revealed that these bacteria are possibly feeding on the outer hyaline spore layer. The process of maturation and eventual germination of AMF spores might then benefit from the activity of the surface microorganisms degrading the outer hyaline wall layer.


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