Light availability and light demand of plants shape the arbuscular mycorrhizal fungal communities in their roots 

2021 ◽  
Author(s):  
Lena Neuenkamp ◽  
Martin Zobel ◽  
Kadri Koorem ◽  
Teele Jairus ◽  
John Davison ◽  
...  
Keyword(s):  
Climate Change ◽  
Woody Plant ◽  
Light Availability ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Fungal Communities ◽  
Mycorrhizal Symbiosis ◽  
Woody Plant Encroachment ◽  
Vegetation Shifts ◽  
Grassland Ecosystems

<p>Woody plant encroachment is influencing many open, grassy ecosystems across the globe, such as savanna, tundra and temperate grassland ecosystems. Drivers of woody plant encroachment are local land use change and global climate change, with shifts in grazing and mowing regimes as important local drivers and elevated CO2 levels, higher temperature and altered precipitation amounts as global drivers. Encroachment of woody species into open, herbaceous ecosystems comes along with substantial shifts in soil conditions, a reduction light availability and ultimately vegetation shifts in the understorey towards species better adapted to the ambient conditions. While vegetation shifts in response to woody plant encroachment in grassy ecosystems have been frequently investigated, e.g. regarding altered plant composition and functional traits related to resource acquisition and dispersal, consequences for biotic interactions have been less studied.</p><p>The symbiosis of plant roots with mycorrhizal fungi is one of the most relevant biotic interaction for plants species, with over 90% of all plants forming mycorrhizal symbiosis and arbuscular mycorrhizal symbiosis as the most prominent mycorrhizal type among herbaceous species. Plants involved in the arbuscular mycorrhizal (AM) symbiosis trade photosynthetically derived carbon for fungal-provided soil nutrients. However, little is known about how plant light demand and ambient light conditions influence root-associating AM fungal communities, and thus their response to prominent climate change processes like shrub encroachment.</p><p>We conducted a manipulative field experiment to test whether plants’ shade tolerance influences their root AM fungal communities in open and shaded grassland sites. We found that light-dependent shifts in AM fungal community structure were similar for experimental bait plant roots and the surrounding soil. Yet, lower AM fungal beta and gamma diversity for shade-intolerant plants in shade likely reflected preferential carbon allocation to specific AM fungi due to the limited plant carbon available to support symbiotic fungi. We conclude that favourable environmental conditions, including optimal light availability, widen the plant biotic niche, i.e. selectivity for specific AM fungi is reduced, and compatibility with a larger number of AM fungal taxa is promoted. With respect to predicted stronger woody plant encroachment predicted under current climate change scenarios, these results indicate that we might be losing AM fungal diversity and the functions associated with these fungal taxa. This calls for continous investment into conservation efforts and management practices to counteract this trend and keep savanna, tundra and grassland ecosystems open. </p>

scholarly journals Arbuscular mycorrhizal symbiosis facilitates apricot seedling (Prunus sibirica L.) growth and photosynthesis in northwest China

2021 ◽  
Author(s):  
Yinli Bi ◽  
Linlin Xie ◽  
Zhigang Wang ◽  
Kun Wang ◽  
Wenwen Liu ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Northwest China ◽  
Shaanxi Province ◽  
Mycorrhizal Symbiosis ◽  
Seedling Physiology ◽  
Grassland Ecosystems ◽  
Time Period ◽  
Seedling Biomass ◽  
Experimental Treatments

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.

scholarly journals Extraction of short chain chitooligosaccharides from fungal biomass and their use as promoters of arbuscular mycorrhizal symbiosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Crosino ◽  
Elisa Moscato ◽  
Marco Blangetti ◽  
Gennaro Carotenuto ◽  
Federica Spina ◽  
...  
Keyword(s):  
Fungal Biomass ◽  
Large Scale ◽  
Low Cost ◽  
Trichoderma Viride ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Production Costs ◽  
Short Chain ◽  
Mycorrhizal Symbiosis ◽  
Major Interest

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.

scholarly journals Target of rapamycin, PvTOR, is a key regulator of arbuscule development during mycorrhizal symbiosis in Phaseolus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manoj-Kumar Arthikala ◽  
Kalpana Nanjareddy ◽  
Lourdes Blanco ◽  
Xóchitl Alvarado-Affantranger ◽  
Miguel Lara
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Target Of Rapamycin ◽  
Mycorrhizal Symbiosis ◽  
Energy Status ◽  
Symbiotic Associations ◽  
Expression Of Genes ◽  
Fungal Symbiosis ◽  
Am Fungus ◽  
Am Symbiosis

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.

Integrating physiological, community, and evolutionary perspectives on the arbuscular mycorrhizal symbiosis

Botany ◽  
2014 ◽  
Vol 92 (4) ◽  
pp. 241-251 ◽  
Author(s):  
Ylva Lekberg ◽  
Roger T. Koide
Keyword(s):  
Evolutionary Biology ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Partner Choice ◽  
Mycorrhizal Symbiosis ◽  
Physiological Processes ◽  
Resource Transfers ◽  
Am Symbiosis ◽  
Controlled Environments ◽  
Natural Settings

Our knowledge of arbuscular mycorrhizal (AM) function is largely based on results from short-term studies in controlled environments. While these have provided many important insights into the potential effects of the symbiosis on the two symbionts and their communities, they may have also inadvertently led to faulty assumptions about the function of the symbiosis in natural settings. Here we highlight the consequences of failing to consider the AM symbiosis from the perspectives of community ecology and evolutionary biology. Also, we argue that by distinguishing between physiological and evolutionary viewpoints, we may be able to resolve controversies regarding the mutualistic vs. parasitic nature of the symbiosis. Further, while most AM research has emphasized resource transfers, primarily phosphate and carbohydrate, our perceptions of parasitism, cheating, bet-hedging, and partner choice would most likely change if we considered other services. Finally, to gain a fuller understanding of the role of the AM symbiosis in nature, we need to better integrate physiological processes of plants and their AM fungi with their naturally occurring temporal and spatial patterns. It is our hope that this article will generate some fruitful discussions and make a contribution toward this end.

scholarly journals Long-term Effects of Mixed Planting on Arbuscular Mycorrhizal Fungal Communities in the Roots and Soils of Juglans mandshurica Plantations

2020 ◽  
Author(s):  
Li Ji ◽  
Yan Zhang ◽  
Yuchun Yang ◽  
Lixue Yang ◽  
Na Yang ◽  
...  
Keyword(s):  
Fungal Community ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Soil Samples ◽  
Fungal Communities ◽  
Juglans Mandshurica ◽  
Mixed Plantations ◽  
Mixed Plantation ◽  
Unique Otus

Abstract Background: Establishing mixed plantations is an effective way to improve soil fertility and increase forest productivity. Arbuscular mycorrhizal (AM) fungi are obligate symbiotic fungi that can promote mineral nutrient absorption and regulate intraspecific and interspecific competition in plants. However, the effects of mixed plantations on the community structure and abundance of AM fungi are still unclear. Illumina MiSeq sequencing was used to investigate the AM fungal community in the roots and soils of pure and mixed plantations (Juglans mandshurica × Larix gmelinii). The objective of this study is to compare the differential responses of the root and rhizosphere soil AM fungal communities of Juglans mandshurica to long-term mixed plantation management.Results: Glomus and Paraglomus were the dominant genera in the root samples, accounting for more than 80% of the sequences. Compared with that in the pure plantation, the relative abundance of Glomus was higher in the mixed plantation. Glomus, Diversispora and Paraglomus accounted for more than 85% of the sequences in the soil samples. The relative abundances of Diversispora and an unidentified genus of Glomeromycetes were higher and lower in the pure plantation, respectively. The Root_P samples (the roots in the pure plantation) had the highest number of unique OTUs (operational taxonomic units), which belonged mainly to an unidentified genus of Glomeromycetes, Paraglomus, Glomus and Acaulospora. The number of unique OTUs detected in the soil was lower than that in the roots. In both the root and soil samples, the forest type did not have a significant effect on AM fungal diversity, but the Sobs value and the Shannon, Chao1 and Ace indices of AM fungi in the roots were significantly higher than those in the soil.Conclusions: Mixed forest management had little effect on the AM fungal community of Juglans mandshurica roots and significantly changed the community composition of the soil AM fungi, but not the diversity.

scholarly journals Differential Response of Mycorrhizal Plants to Tomato bushy stunt virus and Tomato mosaic virus Infection

2020 ◽  
Vol 8 (12) ◽  
pp. 2038
Author(s):  
Neda Khoshkhatti ◽  
Omid Eini ◽  
Davoud Koolivand ◽  
Antreas Pogiatzis ◽  
John N. Klironomos ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Tomato Bushy Stunt Virus ◽  
Uninfected Control ◽  
Tomato Mosaic Virus ◽  
Mycorrhizal Symbiosis ◽  
Pr Genes ◽  
Tomato Plants ◽  
Virus Accumulation

Tomato bushy stunt virus (TBSV) and Tomato mosaic virus (ToMV) are important economic pathogens in tomato fields. Rhizoglomus irregulare is a species of arbuscular mycorrhizal (AM) fungus that provides nutrients to host plants. To understand the effect of R. irregulare on the infection by TBSV/ToMV in tomato plants, in a completely randomized design, five treatments, including uninfected control plants without AM fungi (C), uninfected control plants with AM fungi (M) TBSV/ToMV-infected plants without AM fungi (V), TBSV/ToMV-infected plants before mycorrhiza (VM) inoculation, and inoculated plants with mycorrhiza before TBSV/ToMV infection (MV), were studied. Factors including viral RNA accumulation and expression of Pathogenesis Related proteins (PR) coding genes including PR1, PR2, and PR3 in the young leaves were measured. For TBSV, a lower level of virus accumulation and a higher expression of PR genes in MV plants were observed compared to V and VM plants. In contrast, for ToMV, a higher level of virus accumulation and a lower expression of PR genes in MV plants were observed as compared to V and VM plants. These results indicated that mycorrhizal symbiosis reduces or increases the viral accumulation possibly via the regulation of PR genes in tomato plants.

scholarly journals Arbuscular Mycorrhizal Symbiosis Affects Plant Immunity to Viral Infection and Accumulation

Viruses ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 534 ◽  
Author(s):  
Zhipeng Hao ◽  
Wei Xie ◽  
Baodong Chen
Keyword(s):  
Viral Infection ◽  
Plant Immunity ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Plant Viruses ◽  
Limiting Factors ◽  
Systemic Resistance ◽  
Mycorrhizal Symbiosis ◽  
Complex Nature ◽  
Terrestrial Plants

Arbuscular mycorrhizal (AM) fungi, as root symbionts of most terrestrial plants, improve plant growth and fitness. In addition to the improved plant nutritional status, the physiological changes that trigger metabolic changes in the root via AM fungi can also increase the host ability to overcome biotic and abiotic stresses. Plant viruses are one of the important limiting factors for the commercial cultivation of various crops. The effect of AM fungi on viral infection is variable, and considerable attention is focused on shoot virus infection. This review provides an overview of the potential of AM fungi as bioprotection agents against viral diseases and emphasizes the complex nature of plant–fungus–virus interactions. Several mechanisms, including modulated plant tolerance, manipulation of induced systemic resistance (ISR), and altered vector pressure are involved in such interactions. We propose that using “omics” tools will provide detailed insights into the complex mechanisms underlying mycorrhizal-mediated plant immunity.

Arbuscular mycorrhizal fungal succession in a long-lived perennial

Botany ◽  
2014 ◽  
Vol 92 (4) ◽  
pp. 313-320 ◽  
Author(s):  
Miranda M. Hart ◽  
Monika Gorzelak ◽  
Diane Ragone ◽  
Susan J. Murch
Keyword(s):  
High Throughput Sequencing ◽  
Selective Pressure ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Fungal Communities ◽  
Artocarpus Altilis ◽  
Host Identity ◽  
Arbuscular Mycorrhizal Fungal ◽  
Insight Into

It is difficult to understand why arbuscular mycorrhizal (AM) fungal communities change over time. The role of host identity confounds our understanding of successional changes in AM fungal communities because hosts exert strong selective pressure on their root-associated microbes. In this study we looked at the AM fungi associated with a long-lived perennial breadfruit (Artocarpus altilis (Parkinson) Fosberg) to see how AM communities change over the life span of a single, long-lived host. Using 454 high-throughput sequencing, we found evidence that older trees had more AM fungal taxa than younger trees and were associated with different AM fungal communities, but these differences were not apparent early in the life cycle. Older trees were dominated by species of Rhizophagus, whereas younger trees and genets were dominated by species of Glomus. Some taxa were only detected in older trees (e.g., Funneliformis) or genets (e.g., Racocetra and Scutellospora), indicating that certain AM fungal taxa may serve as “indicators” of the successional age of the fungal community. These results provide important information about a poorly studied system and give insight into how AM communities change over longer time scales.

scholarly journals Photosynthetic performance and stevioside concentration are improved by the arbuscular mycorrhizal symbiosis in Stevia rebaudiana under different phosphate concentrations

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10173
Author(s):  
Luis G. Sarmiento-López ◽  
Melina López-Meyer ◽  
Gabriela Sepúlveda-Jiménez ◽  
Luis Cárdenas ◽  
Mario Rodríguez-Monroy
Keyword(s):  
Stevia Rebaudiana ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
P Uptake ◽  
Photosynthetic Performance ◽  
Phosphate Concentration ◽  
Mycorrhizal Symbiosis ◽  
Steviol Glycosides ◽  
Rebaudioside A ◽  
Carotenoid Concentration

In plants, phosphorus (P) uptake occurs via arbuscular mycorrhizal (AM) symbiosis and through plant roots. The phosphate concentration is known to affect colonization by AM fungi, and the effect depends on the plant species. Stevia rebaudiana plants are valuable sources of sweetener compounds called steviol glycosides (SGs), and the principal components of SGs are stevioside and rebaudioside A. However, a detailed analysis describing the effect of the phosphate concentration on the colonization of AM fungi in the roots and the relationship of these factors to the accumulation of SGs and photochemical performance has not been performed; such an analysis was the aim of this study. The results indicated that low phosphate concentrations (20 and 200 µM KH2PO4) induced a high percentage of colonization by Rhizophagus irregularis in the roots of S. rebaudiana, while high phosphate concentrations (500 and 1,000 µM KH2PO4) reduced colonization. The morphology of the colonization structure is a typical Arum-type mycorrhiza, and a mycorrhiza-specific phosphate transporter was identified. Colonization with low phosphate concentrations improved plant growth, chlorophyll and carotenoid concentration, and photochemical performance. The transcription of the genes that encode kaurene oxidase and glucosyltransferase (UGT74G1) was upregulated in colonized plants at 200 µM KH2PO4, which was consistent with the observed patterns of stevioside accumulation. In contrast, at 200 µM KH2PO4, the transcription of UGT76G1 and the accumulation of rebaudioside A were higher in noncolonized plants than in colonized plants. These results indicate that a low phosphate concentration improves mycorrhizal colonization and modulates the stevioside and rebaudioside A concentration by regulating the transcription of the genes that encode kaurene oxidase and glucosyltransferases, which are involved in stevioside and rebaudioside A synthesis in S. rebaudiana.

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