Diversity characteristics of arbuscular mycorrhizal fungi communities in the soil along successional altitudes of Helan Mountain, arid, and semi-arid regions of China

Interaction between arbuscular mycorrhizal fungi and dark septate endophytes in the root systems of Populus euphratica and Haloxylon ammodendron under different drought conditions in Xinjiang, China

Background and Aims

Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) are known to enhance the tolerance of host plants to biotic and abiotic stresses, but the mechanism of their interaction under natural conditions has not been extensively studied.

Methods

We analyzed the endophytic fungal diversity and colonization characteristics in the typical desert plants Populus euphratica and Haloxylon ammodendron and the relationship between them and environmental factors.

Results

Except for DSE in the roots of H. ammodendron, the colonization rates of AMF and DSE were significantly positively correlated with drought severity. The abundance of AMF and DSE under medium and mild drought conditions was greater than that under severe drought conditions. The root colonization rate and abundance of AMF were lower than those of DSE under the same drought conditions. The species diversity and abundance of AMF and DSE in P. euphratica were greater than those in H. ammodendron. AMF were more susceptible to soil factors such as soil water content, soil nitrogen and phosphorus content, and urease, whereas DSE were more affected by pH.

Conclusion

Drought stress has different effects on AMF and DSE in the roots of P. euphratica and H. ammodendron. DSE have a greater advantage in extremely arid environments. This study demonstrates the interaction between AMF and DSE with the host plants P. euphratica and H. ammodendron as well as their effects on the adaptation of host plants to the desert environment, which can provide a basis for strengthening desert vegetation management.

Elevation Determines Fungal Diversity, and Land Use Governs Community Composition: A Dual Perspective from Gaoligong Mountains

Soil fungi are closely tied to their surrounding environment. While numerous studies have reported the effects of land-use practices or elevations on soil fungi, our understanding of how their community structure and diversity vary with elevation across different land-use practices remains limited. In the present study, by collecting soil samples from four different land uses in the Gaoligong Mountain area, namely shrublands (SLs), coffee plantations (CPs), cornfields (CFs), and citrus orchards (COs), and combining them with the changes in altitude gradients (low: 900 m, medium: 1200 m, high: 1500 m), high-throughput sequencing technology was used to analyze the composition and diversity of soil fungal communities based on the collected soil samples. The results showed that the interaction between land-use types and elevation significantly influenced the structure and diversity of fungal communities, although their relative importance in shaping fungal diversity or community structure varied. Specifically, elevation posed a stronger effect on fungal community alpha-diversity and functional guilds, whereas land-use types had a greater influence over fungal community composition. Our study reveals the individual and combined effects of land-use practices and elevation on the structure and diversity of soil fungal communities in the Gaoligong Mountain region, enhancing our understanding of the distribution patterns and driving mechanisms of soil fungal communities in this biodiversity-rich region.

Diversity Patterns of Plant Communities along an Elevational Gradient in Arid and Semi-Arid Mountain Ecosystems in China

Quantitative classification and ordination are instrumental in improving our understanding of plant community patterns and facilitating effective conservation efforts in national mountain ecosystems worldwide. However, there has been a lack of relevant research focused on arid and semi-arid mountain ecosystems. This study aims to address this gap by investigating the Ningxia Helan Mountain National Nature Reserve (located in Northwest China). We conducted a comprehensive study on the patterns of plant communities and their association with environmental factors across a broad elevation range from 1200 m a.s.l. to 2600 m a.s.l. Our findings revealed the presence of 121 angiosperm species across 41 families, with vegetation classified into six distinct groups through two-way indicator species analysis (TWINSPAN) along the elevational gradient. Notably, the communities of Ulmus, Prunus, and Stipa in the middle elevation range exhibited the highest Shannon-Wiener (SW) and Simpson (SN) diversity indices, and these indices followed a single-peak pattern with increasing elevation. Canonical correspondence analysis (CCA) further revealed six distinct yet interrelated plant communities, revealing elevation (ELE) and the biological aridity index (BK) as the most influential environmental factors influencing plant communities' distribution. This understanding is critically important for biodiversity conservation and the management of ecosystems in arid and semi-arid mountain ecosystems.

Ecology and diversity of arbuscular mycorrhizal fungi (AMF) in rice (Oryza sativa L.) in South India: an ecological analysis of factors influencing AMF in rice fields

AIMS

This study examined the diversity of arbuscular mycorrhizal fungi (AMF), mean spore density (MSD), and root colonization in relation to factors such as agroclimatic zones, rice varieties and soil types in paddy fields of South India. The aim was to understand how these factors influence AMF association in rice, facilitating their effective use as a biological tool in paddy cultivation.

METHODS AND RESULTS

AMF were identified through light microscopy of spores, while MSD and percentage-root-length colonization (PRLC) were measured using standard methods. Correlation and principal component analyses were performed to explore the interrelationships between AMF characteristics and various environmental, soil, and plant variables. Sixteen AMF species were identified across 29 rice varieties from three agroclimatic zones, 6 soil orders, and 18 soil series over 2 seasons. Notably, 70% of chemicalized rice fields lacked AMF spores, and only 50% exhibited root colonization. This study offers new insights into the role of AMF in rice cultivation.

CONCLUSION

The AMF diversity and root colonization in relation to environmental variables underscore their significant impact on AMF in particular crop fields.

Effects of gravel on the water infiltration process and hydraulic parameters of stony soil in the eastern foothills of Helan Mountain, China

The investigation into the impact of gravel on water infiltration process and hydraulic parameters in stony soil could offer a theoretical basis to enhance water availability in rocky mountain area. A one-dimensional vertical infiltration experiment was used in this study. Six groups of gravel content of 0% (CK), 10% (W1), 20% (W2), 30% (W3), 40% (W4) and 50% (W5) were established to explore the changes in the wetting front, cumulative infiltration volume and infiltration rate. Then the accuracy of four infiltration models in simulating soil water infiltration processes was evaluated. Finally, Hydrus-1D was used to perform numerical inversion of the soil water content after infiltration. The findings revealed that: (1) When the infiltration time reached 300 min, the wetting front of the W1, W2, W3, W4 and W5 treatments was 11.00%, 17.00%, 32.25%, 38.75% and 54.50% lower than CK, the cumulative infiltration volume was 29.80%, 38.97%, 45.62%, 54.74% and 73.17% lower than CK, and the stable infiltration rate was 50.98%, 52.94%, 66.67%, 68.63% and 86.27% lower than CK. (2) The soil-water infiltration processes were accurately described by the Horton model, the coefficient of determination (R2) > 0.935. (3) The simulation results of Hydrus-1D showed that with the increase of gravel content, the values of the retention water content (θr), saturated water content (θs), shape coefficient (n) and saturated hydraulic conductivity (Ks) were decreased, the values of the reciprocal of air-entry (α) were increased. The value of R2 was more than 0.894, the root mean square error (RMSE) and mean absolute error (MAE) were less than 2%, which demonstrated that the Hydrus-1D model exhibited superior capability in simulating the changes of water content in stony soil in rocky mountain area. The findings of this study demonstrated that gravel could decrease the water infiltration process and affect the water availability. It could provide data support for the water movement process of stony soil and rational utilization of limited water resources in mountainous area.

Arbuscular Mycorrhizal Fungi Diversity in Sophora japonica Rhizosphere at Different Altitudes and Lithologies

Arbuscular mycorrhizal fungi play a key role in mediating soil-plant relationships within karst ecosystems. Sophora japonica, a medicinal plant with anti-inflammatory and antitumor properties, is widely cultivated in karst areas of Guangxi, China. We considered limestone, dolomite, and sandstone at altitudes ranging from 100 to 800 m and employed Illumina sequencing to evaluate AMF diversity and identify the factors driving S. japonica rhizosphere AMF community changes. We showed that the increase in altitude increased S. japonica AMF colonization and the Shannon index. The colonization of limestone plots was higher than that of other lithology. In total, 3,096,236 sequences and 5767 OTUs were identified in S. japonica rhizosphere soil. Among these, 270 OTUs were defined at the genus level and divided into 7 genera and 35 species. Moreover, available nitrogen, soil organic matter, and available calcium content had a coupling effect and positive influence on AMF colonization and Shannon and Chao1 indices. Conversely, available phosphorus, available potassium, and available magnesium negatively affected AMF Shannon and Chao1 indices. Lithology, altitude, pH, and available phosphorus are important factors that affect the dynamics of AMF in the S. japonica rhizosphere.

Diversity of Arbuscular Mycorrhizal Fungi in Distinct Ecosystems of the North Caucasus, a Temperate Biodiversity Hotspot

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.