scholarly journals The role of local environment and geographical distance in determining community composition of arbuscular mycorrhizal fungi at the landscape scale

2012 ◽  
Vol 7 (3) ◽  
pp. 498-508 ◽  
Author(s):  
Christina Hazard ◽  
Paul Gosling ◽  
Christopher J van der Gast ◽  
Derek T Mitchell ◽  
Fiona M Doohan ◽  
...  
2021 ◽  
Author(s):  
Maede Faghihinia ◽  
Yi Zou ◽  
Yongfei Bai ◽  
Martin Dudáš ◽  
Rob Marrs ◽  
...  

Abstract Arbuscular mycorrhizal fungi (AMF) are the predominant type of mycorrhizal fungi in roots and rhizosphere soil of grass species worldwide. Grasslands are currently experiencing increasing grazing pressure, but it is not yet clear how grazing intensity and host plant grazing preference by large herbivores interact with soil- and root-associated AMF communities. Here, we tested whether the diversity and community composition of AMF in the roots and rhizosphere soil of two dominant perennial grasses grazed differently by livestock change in response to grazing intensity. We conducted a study in a long-term field experiment in which seven levels of field-manipulated grazing intensities were maintained for 13 years in a typical steppe grassland in northern China. We extracted DNA from the roots and rhizosphere soil of two dominant grasses, Leymus chinense (Trin.) Tzvel. and Stipa grandis P. Smirn, with contrasting grazing preference by sheep. AMF DNA from root and soil samples were then subjected to molecular analysis. Our results showed that AMF α-diversity (richness) at the virtual taxa (VT) level varied as a function of grazing intensity. Different VTs showed completely different responses along the gradient, one increasing, one decreasing and others showing no response. Glomeraceae was the most abundant AMF family along the grazing gradient, which fits well with the theory of disturbance tolerance of this group. In addition, sheep grazing preference for host plants did not explain a considerable variation in AMF α-diversity. However, the two grass species exhibited different community composition in their roots and rhizosphere soils. Roots exhibited a lower α-diversity and higher β-diversity within the AMF community than soils. Overall, our results suggest that long-term grazing intensity might have changed the abundance of functionally-diverse AMF taxa in favor of those with disturbance-tolerant traits. We suggest our results would be useful in informing the choice of mycorrhizal fungi indicator variables when assessing the impacts of grassland management choices on grassland ecosystem functioning.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Abeer Hashem ◽  
E. F. Abd_Allah ◽  
A. A. Alqarawi ◽  
A. A. Al-Huqail ◽  
M. A. Shah

The role of soil microbiota in plant stress management, though speculated a lot, is still far from being completely understood. We conducted a greenhouse experiment to examine synergistic impact of plant growth promoting rhizobacterium,Bacillus subtilis(BERA 71), and arbuscular mycorrhizal fungi (AMF) (Claroideoglomus etunicatum;Rhizophagus intraradices; andFunneliformis mosseae) to induce acquired systemic resistance in Talh tree (Acacia gerrardiiBenth.) against adverse impact of salt stress. Compared to the control, the BERA 71 treatment significantly enhanced root colonization intensity by AMF, in both presence and absence of salt. We also found positive synergistic interaction betweenB.subtilisand AMFvis-a-visimprovement in the nutritional value in terms of increase in total lipids, phenols, and fiber content. The AMF and BERA 71 inoculated plants showed increased content of osmoprotectants such as glycine, betaine, and proline, though lipid peroxidation was reduced probably as a mechanism of salt tolerance. Furthermore, the application of bioinoculants to Talh tree turned out to be potentially beneficial in ameliorating the deleterious impact of salinity on plant metabolism, probably by modulating the osmoregulatory system (glycine betaine, proline, and phenols) and antioxidant enzymes system (SOD, CAT, POD, GR, APX, DHAR, MDAHR, and GSNOR).


2020 ◽  
Vol 110 (5) ◽  
pp. 999-1009 ◽  
Author(s):  
Golam Jalal Ahammed ◽  
Qi Mao ◽  
Yaru Yan ◽  
Meijuan Wu ◽  
Yaqi Wang ◽  
...  

Melatonin is a multifunctional molecule that confers tolerance to a number of biotic and abiotic stresses in plants. However, the role of melatonin in plant response to Fusarium oxysporum and the interaction with arbuscular mycorrhizal fungi (AMF) remain unclear. Here we show that exogenous melatonin application promoted the AMF colonization rate in cucumber roots, which potentially suppressed Fusarium wilt as evidenced by a decreased disease index and an increased control effect. Leaf gas exchange analysis revealed that Fusarium inoculation significantly decreased the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentrations (Ci), and transpiration rate (Tr). Intriguingly, either melatonin application or AMF inoculation significantly increased the Pn, Gs, Tr, and dry biomass, and their combined treatment showed a more profound effect under Fusarium stress. Further analysis showed that Fusarium induced oxidative stress as evidenced by increased lipid peroxidation and electrolyte leakage. Conversely, either melatonin or AMF drastically attenuated the levels of malondialdehyde, H2O2, and electrolyte leakage in Fusarium-inoculated plants, and their combined treatment caused a further decrease. Fusarium inoculation decreased the activity and transcripts of superoxide dismutase and ascorbate peroxidase, and the content of glutathione and proline. Besides, the activity and transcripts of peroxidase and catalase, the content of phenols and flavonoids increased after Fusarium infection. Importantly, melatonin and/or AMF significantly increased those parameters with the greatest effect with their combined treatment under Fusarium stress. Our results suggest that a positive collaboration between melatonin and AMF enhances resistance to Fusarium wilt in cucumber plants.


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