1
|
Netherway T, Bahram M. Melanized root-associated fungi: key players in plant-soil systems. Trends Microbiol 2024:S0966-842X(24)00169-0. [PMID: 38987052 DOI: 10.1016/j.tim.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/03/2024] [Accepted: 06/21/2024] [Indexed: 07/12/2024]
Abstract
Melanized root-associated fungi are a group of fungi that produce melanized structures and form root associations, including different mycorrhizal and endophytic symbioses with plants. They are pervasive across terrestrial ecosystems and play an important role in the prevailing soil carbon (C) and nutrient cycling syndromes through direct and indirect mechanisms, where they may strongly modulate plant-microbe interactions and structure root and soil microbiomes. Furthermore, melanized root-associated fungi can confer on plants an enhanced ability to tolerate abiotic and biotic stressors such as drought, extreme temperatures, heavy metals, and pathogen attacks. We propose that melanized root-associated fungi are a cohesive and ecologically relevant grouping that can be an indicator of plant-soil system functioning, and considering them will advance research on plant-soil interactions.
Collapse
Affiliation(s)
- Tarquin Netherway
- Department of Ecology, Swedish University of Agricultural Sciences, Ulls väg 16, 756 51 Uppsala, Sweden.
| | - Mohammad Bahram
- Department of Ecology, Swedish University of Agricultural Sciences, Ulls väg 16, 756 51 Uppsala, Sweden; Department of Agroecology, Aarhus University, Slagelse, Denmark; Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia
| |
Collapse
|
2
|
Are dark septate endophytes an ancestral ecological state in the evolutionary history of the order Chaetothyriales? Arch Microbiol 2023; 205:55. [PMID: 36607426 DOI: 10.1007/s00203-023-03401-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/31/2022] [Accepted: 01/01/2023] [Indexed: 01/07/2023]
Abstract
Dark septate endophytes (DSE) are pigmented fungi that colonize plant roots. They represent a morpho-functional status composed of many species belonging to the phylum Ascomycota, distributed in different orders. The order Chaetothyriales has representatives with diverse lifestyles, among which the rock-inhabiting one has been proposed to be the ancestral ecological character state. However, all taxa have the phenotypic characteristic of being highly melanized. This trait has been considered relevant in most Chaetothyriales because it allows them to tolerate extreme or toxic environmental conditions. In the present study, aiming to reconstruct the evolutionary history of this order, we analyzed the contribution of the DSE habit to the diversification of the Chaetothyriales. We also report the distribution of the DSE habit among the main families and/or clades within the order. Our results suggest that DSE had a key position in the evolution of the order Chaetothyriales, both as an ancestral ecological character and as a character from which other specialized forms such as Domatium probably derived.
Collapse
|
3
|
Malicka M, Magurno F, Piotrowska-Seget Z. Plant association with dark septate endophytes: When the going gets tough (and stressful), the tough fungi get going. CHEMOSPHERE 2022; 302:134830. [PMID: 35525444 DOI: 10.1016/j.chemosphere.2022.134830] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/26/2022] [Accepted: 04/29/2022] [Indexed: 06/14/2023]
Abstract
Dark septate endophytes (DSEs) comprise a diverse and ubiquitous group of fungal generalists with broad habitat niches that robustly colonize the roots of plants in stressful environments. DSEs possess adaptation strategies that determine their high tolerance to heavy metal (HM) contamination, drought, and salinity. Most DSEs developed efficient melanin-dependent and melanin-independent mechanisms of HM detoxification and osmoprotection, including intracellular immobilization and extracellular efflux of HMs and excess ions, and the scavenging of reactive oxygen species. DSEs form mutualistic relationship with plants according to the hypothesis of "habitat-adapted associations", supporting the survival of their hosts under stressful conditions. As saprophytes, DSEs mineralize a complex soil substrate improving plants' nutrition and physiological parameters. They can protect the host plant from HMs by limiting HM accumulation in plant tissues and causing their sequestration in root cell walls as insoluble compounds, preventing further HM translocation to shoots. The presence of DSE in drought-affected plants can substantially ameliorate the physiology and architecture of root systems, improving their hydraulic properties. Plant growth-promoting features, supported by the versatility and easy culturing of DSEs, determine their high potential to enhance phytoremediation and revegetation projects for HM-contaminated, saline, and desertic lands reclamation.
Collapse
Affiliation(s)
- Monika Malicka
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28 Street, 40-032 Katowice, Poland.
| | - Franco Magurno
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28 Street, 40-032 Katowice, Poland
| | - Zofia Piotrowska-Seget
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Jagiellońska 28 Street, 40-032 Katowice, Poland
| |
Collapse
|
4
|
Improved Tolerance of Artemisia ordosica to Drought Stress via Dark Septate Endophyte (DSE) Symbiosis. J Fungi (Basel) 2022; 8:jof8070730. [PMID: 35887485 PMCID: PMC9320036 DOI: 10.3390/jof8070730] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/14/2022] Open
Abstract
Dark septate endophytes (DSEs) usually colonize plant roots, especially in stress environments. However, their relationship with plants ranges from beneficial to harmful and has remained largely uncharacterized. In the present study, 14 DSE species grouped into 11 genera were isolated from the roots of a desert plant, Artemisia ordosica, which is widely distributed in northwest China. Three dominant DSE species—Paraphoma chrysanthemicola (Pc), Alternaria chartarum (Ac), and Acrocalymma vagum (Av)—were selected and tested for their resistance to drought in vitro. Furthermore, we characterized the responses of A. ordosica under drought conditions in relation to the presence of these DSEs following inoculation. The results showed that all three strains grew well under in vitro drought stress, and the biomass of Ac and Av was significantly higher than that of the unstressed control. The effects of DSE inoculation on the growth of A. ordosica under drought stress varied according to the different DSE species but were generally beneficial. Under drought stress, Av and Pc promoted plant growth, antioxidant enzyme activity, and root development of the hosts. The Ac strain conferred obvious positive effects on the antioxidant enzyme activity of the hosts. In general, Av and Pc demonstrated better application potential for improving the drought resistance of A. ordosica.
Collapse
|
5
|
Abstract
The findings on the strategies employed by endophytic microbes have provided salient information to the researchers on the need to maximally explore them as bio-input in agricultural biotechnology. Biotic and abiotic factors are known to influence microbial recruitments from external plant environments into plant tissues. Endophytic microbes exhibit mutualism or antagonism association with host plants. The beneficial types contribute to plant growth and soil health, directly or indirectly. Strategies to enhance the use of endophytic microbes are desirable in modern agriculture, such that these microbes can be applied individually or combined as bioinoculants with bioprospecting in crop breeding systems. Scant information is available on the strategies for shaping the endophytic microbiome; hence, the need to unravel microbial strategies for yield enhancement and pathogen suppressiveness have become imperative. Therefore, this review focuses on the endophytic microbiome, mechanisms, factors influencing endophyte recruitment, and strategies for possible exploration as bioinoculants.
Collapse
|
6
|
Terlizzi NL, Rodríguez MA, Iannone LJ, Lanari E, Novas MV. Epichloë endophyte affects the root colonization pattern of belowground symbionts in a wild grass. FUNGAL ECOL 2022. [DOI: 10.1016/j.funeco.2022.101143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
7
|
Cui Q, He T, Zhang A, Quan X, Feng Y, Chen X, He Y. Effects of soil salinity characteristics on three habitats in inland salt marshes. JOURNAL OF PLANT RESEARCH 2021; 134:1037-1046. [PMID: 34268610 DOI: 10.1007/s10265-021-01328-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Understanding the effect of soil salinity on the diversity and species distribution of plant communities in inland salt marsh ecosystems could provide solutions for the management of regional saline soils and the protection of salt marsh wetland vegetation. A field experiment in succulent halophyte, Carex, and gramineous grass habitats in Ordos, Inner Mongolia (northwest China) was conducted to study the diversity and composition of plants in different saline habitats in inland salt marsh ecosystems. Results showed that plant diversity and species richness in the Carex habitat were significantly higher than the succulent halophyte habitat and the gramineous grass habitat (P < 0.05). Further, species abundance was higher in the succulent halophyte habitat and the Carex habitat than the gramineous grass habitat. Similar results were obtained when considering the abundance of constructive species. No significant differences in the abundance of dominant species and companion species between the gramineous grass habitat and the Carex habitat were found. We concluded that species abundance, species richness, species distribution, and plant diversity together explained the response of plant communities in different habitats to soil salinity, especially Na+ and SO42-. This highlights the importance of soil salinity for the maintenance of plant diversity and structural composition in inland salt marsh ecosystems.
Collapse
Affiliation(s)
- Qiao Cui
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China
| | - Tonghui He
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China.
| | - Anning Zhang
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China
| | - Xiaosai Quan
- College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, 750021, China
| | - Yanqiong Feng
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China
| | - Xiangquan Chen
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China
| | - Yushi He
- Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwestern China of Ministry of Education, Ningxia University, Yinchuan, 750021, China
| |
Collapse
|
8
|
Zuo Y, Li X, Yang J, Liu J, Zhao L, He X. Fungal Endophytic Community and Diversity Associated with Desert Shrubs Driven by Plant Identity and Organ Differentiation in Extremely Arid Desert Ecosystem. J Fungi (Basel) 2021; 7:jof7070578. [PMID: 34356957 PMCID: PMC8306007 DOI: 10.3390/jof7070578] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 12/23/2022] Open
Abstract
Despite desert ecosystem being crucial to our understanding of natural geography, species evolution and global climate change, there is limited information on the dynamics of their composition and the diversity of endophytic fungi communities driven by plant identity and organ differentiation. Here, an extensive investigation of endophytic fungal microbiome in root, stem, and leaf organs associated with five xerophyte shrubs in an extremely arid desert, Northwest China, were examined. The fungal community dominated by Dothideomycetes and Pleosporales. Shrub species strongly drive the niche-based processes of endophytic fungi across the root, stem and leaf compartments. The diversity and composition of endophytic fungi in stem showed higher variability among plant species than leaf and root. The fungal communities in root libraries were more diverse and exhibited a remarkable differentiation of community composition. We further demonstrated the significant host preferences and tissue specificity of desert endophytic fungi, and unique specific taxa were also observed. The co-occurrence network revealed the coexistence of fungal endophytes in arid desert, and the root fungal network harbored the highest interspecies connectivity. Members of Pleosporales were the most common keystone species in the root fungal network. This is the first report of mycobiota in both plant species and organ differentiation in an extremely arid desert ecosystem.
Collapse
Affiliation(s)
| | | | | | | | | | - Xueli He
- Correspondence: ; Tel.: +86-31-2507-9364
| |
Collapse
|
9
|
He C, Wang W, Hou J, Li X. Dark Septate Endophytes Isolated From Wild Licorice Roots Grown in the Desert Regions of Northwest China Enhance the Growth of Host Plants Under Water Deficit Stress. Front Microbiol 2021; 12:522449. [PMID: 34248857 PMCID: PMC8260703 DOI: 10.3389/fmicb.2021.522449] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/20/2021] [Indexed: 11/13/2022] Open
Abstract
This study aimed to explore dark septate endophytes (DSE) that may improve the cultivation of medicinal plants in arid ecosystems. We isolated and identified eight DSE species (Acremonium nepalense, Acrocalymma vagum, Alternaria chartarum, Alternaria chlamydospora, Alternaria longissima, Darksidea alpha, Paraphoma chrysanthemicola, and Preussia terricola) colonizing the roots of wild licorice (Glycyrrhiza uralensis) in the desert areas of northwest China. Moreover, we investigated the osmotic stress tolerance of the DSE using pure culture, along with the performance of licorice plants inoculated with the DSE under drought stress in a growth chamber, respectively. Here, five species were first reported in desert habitats. The osmotic-stress tolerance of DSE species was highly variable, A. chlamydospora and P. terricola increased the total biomass and root biomass of the host plant. All DSE except A. vagum and P. chrysanthemicola increased the glycyrrhizic acid content; all DSE except A. chartarum increased the glycyrrhizin content under drought stress. DSE × watering regimen improved the glycyrrhizic acid content, soil organic matter, and available nitrogen. Structural equation model analysis showed that DSE × watering regimen positively affected soil organic matter, and total biomass, root length, glycyrrhizic acid, and glycyrrhizin (Shapotou site); and positively affected soil organic matter, available phosphorus, and glycyrrhizin (Minqin site); and positively affected the root length (Anxi site). DSE from the Shapotou site accounted for 8.0, 13.0, and 11.3% of the variations in total biomass, root biomass, and active ingredient content; DSE from the Minqin site accounted for 6.6 and 8.3% of the variations in total biomass and root biomass; DSE from the Anxi site accounted for 4.2 and 10.7% of the variations in total biomass and root biomass. DSE × watering regimen displayed a general synergistic effect on plant growth and active ingredient contents. These findings suggested that the DSE-plant interactions were affected by both DSE species and DSE originating habitats. As A. chlamydospora and P. terricola positively affected the total biomass, root biomass, and active ingredient content of host plants under drought stress, they may have important uses as promoters for the cultivation of licorice in dryland agriculture.
Collapse
Affiliation(s)
- Chao He
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Wenquan Wang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing, China
| | - Junling Hou
- School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing, China
| | - Xianen Li
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| |
Collapse
|
10
|
Soil nutrients differentially influence root colonisation patterns of AMF and DSE in Australian plant species. Symbiosis 2021. [DOI: 10.1007/s13199-021-00748-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
11
|
Zhou Z, Yu M, Ding G, Gao G, He Y, Wang G. Effects of Hedysarum leguminous plants on soil bacterial communities in the Mu Us Desert, northwest China. Ecol Evol 2020; 10:11423-11439. [PMID: 33144975 PMCID: PMC7593153 DOI: 10.1002/ece3.6779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 11/19/2022] Open
Abstract
This study assessed the influence of rhizocompartment types (i.e., root, rhizosphere soil, root-zone soil, and intershrub bulk soil) on the diversity of soil microbial communities under desert leguminous plant shrubs. Moreover, the influence and variations of soil physicochemical factors in interactions among leguminous plants, soil, and microbes were investigated. Both 16S rRNA high-throughput genome sequencing and conventional soil physicochemical index determination were used to characterize both the bacterial diversity and soil physicochemical properties in the rhizocompartments of two Hedysarum species (Hedysarum mongolicum and Hedysarum scoparium) in the Mu Us Desert of China. All nutrient indices (except total phosphorus and available phosphorus) in rhizosphere soil were uniformly higher than those in both root-zone soil and intershrub bulk soil (p < .05). The bacterial community diversity in the root, undershrub soil (i.e., rhizosphere and root zone), and intershrub bulk soil also showed significant differences (p < .05). The bacterial community in the root is mainly composed of Proteobacteria, Actinobacteria, Bacteroidetes, Tenericutes, and Chloroflexi, among which bacteria of the Proteobacteria genus are dominant. Root endophyte and rhizosphere soil microbiomes were mainly influenced by soil nutrients, while bacterial communities in root-zone soil and intershrub bulk soil were mainly influenced by soil pH and NH4 +-N. The rhizocompartment types of desert leguminous plants impose a significant influence on the diversity of soil microbial communities. According to these findings, nitrogen-fixing rhizobia can co-exist with nonsymbiotic endophytes in the roots of desert leguminous plants. Moreover, plants have a hierarchical filtering and enriching effect on beneficial microbes in soil via rhizocompartments. Soil physicochemical factors have a significant influence on both the structure and composition of microbial communities in various rhizocompartments, which is derived from the interactions among leguminous plants, soil, and microbes.
Collapse
Affiliation(s)
- Ziyuan Zhou
- Yanchi Research StationSchool of Soil and Water ConservationBeijing Forestry UniversityBeijingChina
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| | - Minghan Yu
- Yanchi Research StationSchool of Soil and Water ConservationBeijing Forestry UniversityBeijingChina
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| | - Guodong Ding
- Yanchi Research StationSchool of Soil and Water ConservationBeijing Forestry UniversityBeijingChina
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| | - Guanglei Gao
- Yanchi Research StationSchool of Soil and Water ConservationBeijing Forestry UniversityBeijingChina
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| | - Yingying He
- Yanchi Research StationSchool of Soil and Water ConservationBeijing Forestry UniversityBeijingChina
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| | - Genzhu Wang
- Key Laboratory of State Forestry Administration on Soil and Water ConservationBeijing Forestry UniversityBeijingChina
| |
Collapse
|
12
|
Dark Septate Endophytic Fungi Associated with Sugarcane Plants Cultivated in São Paulo, Brazil. DIVERSITY 2020. [DOI: 10.3390/d12090351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dark septate endophytes (DSEs) constitute a polyphyletic group within the Ascomycota, with global distribution and a wide range of host plant species. The present study evaluated the diversity of DSE in sugarcane roots of the varieties RB867515, RB966928, and RB92579, and four varieties of not commercialized energy cane. A total of 16 DSE strains were isolated, mostly from the varieties RB966928 and RB867515, with six and five isolates, respectively. Just one of the four energy cane varieties had fungi with DSE appearance. The analyses of the DNA sequences from the internal transcribed spacer (ITS) and the large subunit (LSU), in association with the micromorphology of the isolates, allowed the differentiation of the 16 isolates in at least five species, within the families Periconiaceae, Pleosporaceae, Lentitheciaceae, Vibrisseaceae, and Apiosporaceae and the orders Pleosporales, Helotiales, and Xylariales. The order Pleosporales represented 80% of the isolates, and the species Periconia macrospinosa, with six isolates, accounted for the highest isolation frequency. The results confirm the natural occurrence of the DSE symbiosis in sugarcane varieties and the generalist character of these fungi as some of the detected species have already been reported associated with other host plants, ecosystems, and regions of the world.
Collapse
|
13
|
Colonization by dark septate endophytes improves the growth of Hedysarum scoparium under multiple inoculum levels. Symbiosis 2020. [DOI: 10.1007/s13199-020-00713-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
14
|
Preparation of Green Low Strength Mixture for Foundation Reinforcement Treatment by Using Fly Ash and Waste Coal Gangue. MATERIALS 2020; 13:ma13030664. [PMID: 32024299 PMCID: PMC7040594 DOI: 10.3390/ma13030664] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/20/2020] [Accepted: 01/29/2020] [Indexed: 11/17/2022]
Abstract
Effective foundation reinforcement treatment is essential for modern large and complex infrastructure, while it is significant for developing new green high-performance materials for foundation reinforcement. This study investigates a new green concrete by using high volume fly-ash and coal gangue aggregates, which is expected to apply for foundation treatment of modern infrastructure with high loading-bear ability. In this experiment, 12 mix proportions of fly ash coal gangue mixture (the material name, abbreviated FGM) were designed, and its mechanical properties and durability performance were investigated. The mechanical properties of FGM include compressive strength, dynamic elastic modulus, dynamic shear modulus, Poisson's ratio, and the stress-strain behaviors. The durability performance was evaluated by the parameters of acid resistance, which simulated an acid circumstance. After that, the environmental effects about carbon emission of this material were also investigated. Results show that the FGM with 84.6% wastes utilizing rate is a cost-effective material for foundation reinforcing treatment. Its compressive strength at 28 days and 60 days can reach more than 8 MPa and 10 MPa, respectively. After being immersed in the acid environment for 140 days, the mass loss (%) of the material could be under 3.5%. The greenness shows that the e-CO2 indices of FGM are lower than 20 kg/MPa·m3, and the e-energy indices are at below 150 MJ/MPa·m3. FGM has the advantages of acid resistance, waste recycling, and lower carbon emissions than the previous methods for foundation improvement.
Collapse
|
15
|
Knapp DG, Imrefi I, Boldpurev E, Csíkos S, Akhmetova G, Berek-Nagy PJ, Otgonsuren B, Kovács GM. Root-Colonizing Endophytic Fungi of the Dominant Grass Stipa krylovii From a Mongolian Steppe Grassland. Front Microbiol 2019; 10:2565. [PMID: 31781068 PMCID: PMC6861457 DOI: 10.3389/fmicb.2019.02565] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/23/2019] [Indexed: 11/25/2022] Open
Abstract
In several terrestrial ecosystems such as grasslands, plants live together with various root-colonizing dark septate endophytes (DSEs), fungi that are relatively frequent colonizers of healthy belowground tissues of plants in these environments. They are important members of the plant microbiota and may have various effects on plant survival under different stress conditions; however, their general functions in relation to plants and the greater ecosystem remain elusive. Although an increasing number of studies has been published focusing on DSEs in Asian grasslands, our knowledge is limited. Especially in Mongolia, where the steppe region represents a significant area, information is not available on these root colonizers. In this study, we aimed to characterize DSEs of a common dominant gramineous plant species, Stipa krylovii in a semiarid grassland of Mongolia. Root samples were collected in a natural steppe and were processed for isolation of fungal endophytes. For molecular identification of the isolates, the internal transcribed spacer (ITS) region of the nrDNA was obtained for all the isolates investigated; furthermore, the partial translation elongation factor 1-α (TEF) gene and large subunit (LSU) and small subunit (SSU) of rDNA were also amplified and sequenced in case of representative isolates. In vitro tests were used to examine the rough symbiotic nature of the fungi, and root colonization was visualized. A majority of the 135 isolates examined in detail was found to belong to several orders of Ascomycota (110 isolates) and some to Basidiomycota (25 isolates). A significant number of the isolates represented presumably novel taxa, and dominant similarities of the lineages have been found with relatively frequent and known grass root endophytes of semiarid areas in other geographic regions. These endophytes included Periconia macrospinosa, Microdochium bolley, and Darksidea, the genus of which comprised one fourth of the isolates. We found numerous lineages, which have been detected not only from Asian steppe ecosystems, but also from prairies in North America and sandy grasslands in Europe. Therefore, our results strengthen the hypothesized worldwide presence of a common and dominant core group of a DSE community in arid and semiarid grasslands.
Collapse
Affiliation(s)
- Dániel G. Knapp
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Ildikó Imrefi
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Enkhtuul Boldpurev
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Sándor Csíkos
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Galiya Akhmetova
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Péter János Berek-Nagy
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | | | - Gábor M. Kovács
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| |
Collapse
|