Search Results (8)

The objective of the present study was to revise the recently described order Entrophosporales of the Glomeromycetes. The single family Entrophosporaceae had been divided into three genera, Entrophospora, Claroideoglomus and Albahypha, due to molecular phylogenetic or morphological analyses, but recently these three genera were combined within the type genus of the family, Entrophospora. Our new studies now suggest once more three genera, but Entrophospora and Claroideoglomus were not separated again. In the present study, we resurrected Albahypha with A. drummondii and A. furrazolae comb. nov. and established Alborhynchus gen. nov. with A. walkeri comb. nov. Morphologically, all glomoid morphs of the three genera have hyaline to white subtending hyphae with one spore wall continuous with the subtending hyphal wall. However, the genera can easily be differentiated from each other and from other glomoid species of the Glomeromycetes by the combination of the characteristics of the subtending hyphae, the staining reaction of the spore wall layers in Melzer’s reagent and phylogeny. In conclusion, the three AMF genera, currently recognized in the Entrophosporales, can unequivocally be identified by molecular phylogeny or by morphological characteristics of their spores and their subtending hyphae. An identification key distinguishes all AMF species currently attributed to Entrophosporales. Full article

Researchers are exploring plant-based protein sources to address both malnutrition and climate change. Desert truffles are rich in protein (i.e., $\approx$20%) and offer a cheaper and more environmentally friendly option. However, desert truffle cultivation is limited by environmental factors like rainfall and soil properties. This study was conducted to understand the soil conditions and microbiomes associated with desert truffles growing in parts of Saudi Arabia. Based on yield, the truffle fields were categorized into high-yield ($\approx$50 kg/ha annually) and low-yield ($\approx$2 kg/ha annually) truffle farms. Truffle yield differences were not significantly influenced by most soil physicochemical variables except for total nitrogen (negatively correlated). However, low soil nitrogen alone did not explain yield disparities, as wild truffle fields with low nitrogen also produced fewer truffles. In contrast, truffle yield showed a strong positive correlation with calcium carbonate content. We hypothesized that the unmeasured irrigation schedule was most likely behind the truffle yield differences especially during fruiting season. Furthermore, the high-yield farms had lower bacteria richness and diversity than the low-yield farms. Environmentally important bacteria genera such as Geodermatophilus and Rubrobacter were found in both farms, although more were found in the low-yield one, whereas more Streptomyces were found in the high-yield farm. In addition, fungal alpha diversity was higher in the high-yield farm with the dominance of Sordariomycetes, Dothideomycetes, Eurotiomycetes, and Glomeromycetes. Full article

Based on molecular phylogenetic analyses, and also considering morphological characters, four new families are separated from the family Glomeraceae within the order Glomerales and the class Glomeromycetes. The revised family Glomeraceae comprises only four genera: the type genus Glomus, Complexispora, Sclerocarpum and Simiglomus. Septoglomeraceae fam. nov. comprises, besides Septoglomus, Funneliformis, Funneliglomus, Blaszkowskia and Viscospora. Sclerocystaceae fam. nov. is represented by the type genus Sclerocystis but also by Halonatospora, Oehlia, Parvocarpum, Rhizoglomus and Silvaspora. Kamienskiaceae fam. nov. encompasses Kamienskia, Microkamienskia and Epigeocarpum. Finally, Dominikiaceae fam. nov. includes the genera Dominikia, Macrodominikia gen. nov., Microdominikia, Nanoglomus and Orientoglomus. The genera Oehlia and Halonatospora form two other clades well separated from Silvaspora, Sclerocystis and Rhizoglomus and might represent two further families within Glomerales. This deeper separation is, in our opinion, fully supported by molecular phylogeny, but in view of the low numbers of taxa, the separation is not yet proposed at this stage of research progress. Full article

Background: Investigations that are focused on arbuscular mycorrhizal fungus (AMF) biodiversity is still limited. The analysis of the AMF taxa in the North Caucasus, a temperate biodiversity hotspot, used to be limited to the genus level. This study aimed to define the AMF biodiversity at the species level in the North Caucasus biotopes. Methods: The molecular genetic identification of fungi was carried out with ITS1 and ITS2 regions as barcodes via sequencing using Illumina MiSeq, the analysis of phylogenetic trees for individual genera, and searches for operational taxonomic units (OTUs) with identification at the species level. Sequences from MaarjAM and NCBI GenBank were used as references. Results: We analyzed >10 million reads in soil samples for three biotopes to estimate fungal biodiversity. Briefly, 50 AMF species belonging to 20 genera were registered. The total number of the AM fungus OTUs for the “Subalpine Meadow” biotope was 171/131, that for “Forest” was 117/60, and that for “River Valley” was 296/221 based on ITS1/ITS2 data. The total number of the AM fungus species (except for virtual taxa) for the “Subalpine Meadow” biotope was 24/19, that for “Forest” was 22/13, and that for “River Valley” was 28/24 based on ITS1/ITS2 data. Greater AMF diversity, as well as number of OTUs and species, in comparison with that of forest biotopes, characterized valley biotopes (disturbed ecosystems; grasslands). The correlation coefficient between “Percentage of annual plants” and “Glomeromycota total reads” r = 0.76 and 0.81 for ITS1 and ITS2, respectively, and the correlation coefficient between “Percentage of annual plants” and “OTUs number (for total species)” was r = 0.67 and 0.77 for ITS1 and ITS2, respectively. Conclusion: High AMF biodiversity for the river valley can be associated with a higher percentage of annual plants in these biotopes and the active development of restorative successional processes. Full article

Soil microorganisms are greatly affected by their microenvironment. To reveal the influence of different land use patterns on the composition and diversity of soil bacterial and fungal communities, this study analyzed microbial (bacteria and fungi) community composition and diversity under different land use patterns (vegetable land, wasteland, woodland, cultivated land) based on 16S rRNA, 18S rRNA, and high-throughput sequencing method in the Taojia River Basin. Spearman analysis and redundancy analysis (RDA) were used to explore the correlation between soil physicochemical properties and soil fungal and bacterial community composition, and a partial least squares path model (PLS-PM) was constructed to express the causal relationship between soil physicochemical properties and soil bacterial and fungal community diversity. The results showed that the soil bacterial species richness was highest in vegetable land and the lowest in the wasteland. Proteobacteria is the dominant phylum (20.69%–32.70%), and Actinobacteria is the dominant class (7.99%–16.95%). The species richness of fungi in woodland was the highest, while was the lowest in cultivated land. The dominant phylum of fungi in vegetable land, woodland, and cultivated land is Mucoromycota, 29.39%, 41.36%, and 22.67%, respectively. Ascomycota (42.16%) is the dominant phylum in wasteland. Sordariomyetes of Ascomycota is the dominant class in wasteland and cultivated land. Mortierellomycetes and Glomeromycetes of Mucoromycota are the dominant class in vegetable land and woodland. The results of the Spearman analysis revealed that the dominant groups in the bacterial and fungal communities had significant correlations with soil pH, clay, and sand (p < 0.01). The RDA results showed that soil clay, pH, and moisture were the key environmental factors affecting the diversity of soil microbial communities. Fungal diversity is more affected by different land use patterns than bacteria. These results provided a theoretical basis for the changes in soil microbial community composition and diversity in river basins. Full article

Cover crops (CCs) were found to improve soil health by increasing plant diversity and ground cover. They may also improve water supply for cash crops by reducing evaporation and increasing soil water storage capacity. However, their influence on plant-associated microbial communities, including symbiotic arbuscular mycorrhizal fungi (AMF), is less well understood. In a corn field trial, we studied the response of AMF to a four-species winter CC, relative to a no-CC control, as well as to two contrasting water supply levels (i.e., drought and irrigated). We measured AMF colonization of corn roots and used Illumina MiSeq sequencing to study the composition and diversity of soil AMF communities at two depths (i.e., 0–10 and 10–20 cm). In this trial, AMF colonization was high (61–97%), and soil AMF communities were represented by 249 amplicon sequence variants (ASVs) belonging to 5 genera and 33 virtual taxa. Glomus, followed by Claroideoglomus and Diversispora (class Glomeromycetes), were the dominant genera. Our results showed interacting effects between CC treatments and water supply levels for most of the measured variables. The percentage of AMF colonization, arbuscules, and vesicles tended to be lower in irrigated than drought sites, with significant differences detected only under no-CC. Similarly, soil AMF phylogenetic composition was affected by water supply only in the no-CC treatment. Changes in the abundance of individual virtual taxa also showed strong interacting effects between CCs, irrigation, and sometimes soil depth, although CC effects were clearer than irrigation effects. An exception to these interactions was soil AMF evenness, which was higher in CC than no-CC, and higher under drought than irrigation. Soil AMF richness was not affected by the applied treatments. Our results suggest that CCs can affect the structure of soil AMF communities and modulate their response to water availability levels, although soil heterogeneity could influence the final outcome. Full article

Cassava (Manihot esculenta Crantz) is mainly cultivated in marginal land in the south of China where seasonal drought stress occurs frequently and the soil becomes more compact year by year. The study aimed to explore the effect of Fenlong tillage (FLT) combined with nitrogen applications on cassava rhizosphere soil particle composition and fungal community diversity. Conventional tillage (CT) was set as the control. The results indicated that the contents of clay and silt of the cassava rhizosphere soil were influenced by the tillage method, nitrogen (N), and their interaction. There was no difference in the richness and diversity of rhizosphere soil fungal communities among all treatments in 2019, while the richness of FLT was lower than that of CT in 2020. FLT caused a stronger influence on the community structure of rhizosphere fungi than N applications in the first year. The differences in the community structure of all treatments were reduced by continuous cropping of cassava in the second year. The top 10 dominant rhizosphere fungi at the class level of cassava found in 2019 and 2020 were Sordariomycetes, Dothideomycetes, Eurotiomycetes, Agaricomycetes, Intramacronucleata, norank_p__Mucoromycota, unclassified_p__Ascomycota, unclassified_k__Fungi, Pezizomycetes, and Glomeromycetes, which had an important relationship with soil pH, activity of urease, available nitrogen, available phosphorus, organic matter, and clay. These results indicated that FLT created a better soil environment for cassava growth than CT, thus promoting the formation of more stable rhizosphere fungal community structures. Full article

Floods are frequent natural disasters and could have serious impacts on aquatic environments. Eukaryotic communities in artificial canals influenced by floods remain largely unexplored. This study investigated the spatiotemporal variabilities among eukaryotes in response to floods in the Grand Canal, China. Generally, 781,078 sequence reads were obtained from 18S rRNA gene sequencing, with 304,721 and 476,357 sequence reads detected before and after flooding, respectively. Sediment samples collected after the floods exhibited a higher degree of richness and biodiversity but lower evenness than those before the floods. The eukaryotic communities changed from Fungi-dominated before floods to Stramenopile-dominated after floods. The spatial turnover of various species was the main contributor to the longitudinal construction of eukaryotes both before the floods (β_SIM = 0.7054) and after the floods (β_SIM = 0.6858). Some eukaryotic groups responded strongly to floods and might pose unpredictable risks to human health and environmental health. For example, Pezizomycetes, Catenulida, Glomeromycetes, Ellipura, etc. disappeared after the floods. Conversely, Lepocinclis, Synurale, Hibberdiales, Acineta, Diptera, and Rhinosporidium were all frequently detected after the floods, but not prior to the floods. Functional analyses revealed amino acid metabolism, carbohydrate metabolism, translation, and energy metabolism as the main metabolic pathways, predicting great potential for these processes in the Grand Canal. Full article