Diversity and distribution of arbuscular mycorrhizal fungi along a land use gradient in Terceira Island (Azores)

Microorganism community structure: A characterisation of agrosystems from Madeira Archipelago

Microbial diversity profoundly influences soil ecosystem functions, making it vital to monitor community dynamics to comprehend its structure. Our study focused on six agrosystems in Madeira Archipelago, analysing bacteria, archaea, fungi and AMF through classical microbiology and molecular techniques. Despite distinct edaphoclimatic conditions and management practices, bacterial structures exhibited similarities, with Alphaproteobacteria at 18%-20%, Bacilli at 11%-18% and Clostridia at 9%-14%. The predominance of copiothrophic groups suggested that soil nutrient content was the driver of these communities. Regarding archaea, the communities changed among sites, and it was evident that agrosystems provided niches for methanogens. The Crenarchaeota varied between 15% and 29%, followed by two classes of Euryarchaeota, Methanomicrobia (17%-25%) and Methanococci (4%-32%). Fungal communities showed consistent composition at the class level but had differing diversity indices due to management practices and soil texture. Sordaryomycetes (21%-28%) and Agaricomycetes (15%-23%) were predominant. Conversely, AMF communities appeared to be also influenced by the agrosystem, with Glomus representing over 50% of the community in all agrosystems. These insights into microbial groups' susceptibilities to environmental conditions are crucial for maintaining healthy soil and predicting climate change effects on agrosystems' productivity, resilience and sustainability. Additionally, our findings enable the development of more robust prediction models for agricultural practices.

Impact of ecological stages on the soil microbiota and soil abiotic factors in tropical and subtropical Brazilian regions

Our aim was to test if ecological stages may influence the arbuscular mycorrhizal fungi (AMF), nematodes, and the soil chemical properties in agroforestry systems (AF), unassisted forest restoration (UFR), and natural ecosystem (Ne) located in the Brazilian Tropical and Subtropical regions. We collected soil samples to determine AMF, nematodes, soil pH, P, and soil organic carbon (SOC). AMF and nematode richness in the AF and Ne were similar in the tropical region. The redundancy analysis (RDA) indicated that the abundance of AMF and soil nematodes was mainly affected by soil pH, P, and SOC. Differences were associated with (1) ecological stages, as we found differences in AMF and nematode abundance as affected by habitat simplification, and (2) changes in soil pH, SOC, and P. Our work increases the understanding of the AMF and soil nematode community in the rhizosphere of AF and Ne in tropical and subtropical regions.

Molecular Diversity and Distribution of Arbuscular Mycorrhizal Fungi at Different Elevations in Mt. Taibai of Qinling Mountain

Arbuscular mycorrhizal fungi (AMFs) play a vital role in ecosystems, especially in ecosystem variability, diversity, and function. Understanding the AMF diversity, distribution, and their driver at different altitudinal gradients is a benefit for understanding the ecological function of AMF in mountain ecosystems. In this study, we explored the AMF molecular diversity and their distribution from 660 to 3,500 m a.s.l. in Mount Taibai of Qinling Mountains based on high-throughput sequencing technology. A total of 702 operational taxonomic units (OTUs) in 103 species of AMF are isolated from soil samples, which belong to 18 identified and 1 unidentified genus in 10 families. The fungi in the genus of Glomus is the most dominant, with the occurrence frequency of 100% and the relative abundance of 42.268% and 33.048% on the species and OTU level, respectively. The AMF colonization in root could be simulated by a cubic function with the change of altitudes with the peak and trough at a.s.l. 1,170 and 2,850 m, respectively. Further, AMF diversity indices including Sob, Shannon diversity, and Pielou evenness also showed the same cubic function change trends with increasing altitude at OTU and species levels. However, the average values of diversity indices at OTU level are always higher than these at the species level. Based on the OTU level, the highest and lowest values of Shannon and Pielou indices are observed at the altitudes of 1,400 and 2,800 m, respectively. The pattern of AMF community distribution in Mt. Taibai is driven by altitude with the characteristics of more abundance in the medium- to low-altitude than high-altitude areas. In general, abundant AMF molecular diversity and species exit in different elevations of Mt. Taibai, which indicate gradient changes with elevations.

The Response of Arbuscular Mycorrhizal Fungal Communities to the Soil Environment of Underground Mining Subsidence Area in Northwest China

Fully mechanized mining technology applied over a very large working face is typically utilized for coal exploitation in Northwest China and triggered two types of land subsidence above the goaf edge and center. However, the effects of mining subsidence on arbuscular mycorrhizal fungal (AMF) communities are still unknown. Here, we investigated the soil physicochemical properties and the response of AMF communities to the soil environment at the margin and center of the subsidence area of the same working face. Our results showed the soil water content, nutrient content and enzyme activity were significantly decreased with land desertification at the margin of the subsidence area but were less affected at the subsidence center. Utilizing high-throughput sequence analysis, six Glomeromycotan genera were detected. The relative abundance of Glomus and Ambispora at the margin of the subsidence area decreased, while Paraglomus and Diversispora increased. The total OTU richness was significantly correlated with moisture. Redundancy analysis showed the main environmental factors driving the changes in AMF community structure were available nitrogen, available potassium and available phosphorus. All these results indicated land cracks need to be repaired in time at subsidence edge to prevent the decline of soil fertility.