Linking Soil Chemical Parameters and Arbuscular Mycorrhizal Fungal Communities in Qatar

Much of Qatar’s habitats are characterized by a hyper-arid climate, low rainfall and scarce soil nutrients; all of which combine to create a stress-induced environment for fungal development. Agricultural productivity and soil fertility in turn, are highly dependent on the diversity of soil microbiota. The soil environment is a heterogeneous habitat shaped by various components including soil chemical properties and habitat types i.e. wetlands, barren land and grasslands. Arbuscular mycorrhizal fungi (AMF) are one of the key components vital for ecological processes in stress-induced systems as the complex hyphae systems of AMF assemblages permit sufficient nutrient exchange in mycorrhiza symbionts. However, much of the diversity and community composition of AMF in Qatar are poorly studied. In this study, Illumina sequencing by MiSeq platform was used to identify and explore the diversity and composition of AMF communities. Our results revealed 127 virtual taxa (VTs) from eight AMF families, 87 of which were identified as species from Glomeraceae family; while indicator analysis showed that Glomeraceae species served as the indicator species in 15 sites with an indicator index value of 13.33 (indicator value > 0.25)

Linking Soil Chemical Parameters and Fungal Diversity in Qatar

Given the vast expanse of Qatar's dryland ecosystems, agricultural productivity and soil stability is highly dependent on the diversity of soil microbiota. The soil environment is a heterogeneous habitat shaped by various components like chemical (organic matter, salinity and nutrients) and biological (fungal diversity and vegetation) properties that form multitudes of different microhabitats. Soil microbial diversity changes along environmental gradients. It is hypothesized that a "stable" microhabitat is one that is inhabited by a large diversity of established microorganisms that are best adapted to the niche. Microorganisms like fungi serve as the underlying biological drivers for biochemical processes within the soil. The key objective of this study is to evaluate the fungal diversity and abundance present within the Qatari soil using molecular-based tools and evaluate potential relationships between the identified fungal communities with chemical properties of the habitat. We found that the composition of fungi and AMF varied between different habitats around Qatar. Despite the lack of significant differences in the measured soil chemical parameters between sampled sites, it is evident that AMF species are more abundant than compared to that of other fungal species in most of the study sites; thus, suggesting that other factors like land use may also be an essential component explaining the variation in fungal communities

Novel approach to study the diversity of soil microbial communities in Qatar

A broad diversity of microorganisms can be found in soil, where they are essential for nutrient cycling and energy transfer. Recent high-throughput sequencing methods have greatly advanced our knowledge about how soil, climate and vegetation variables structure the composition of microbial communities in many world regions. However, we are lacking information from several regions in the world, e.g. Middle-East. We have collected soil from 19 different habitat types for studying the diversity and composition of soil microbial communities (both fungi and bacteria) in Qatar and determining which edaphic parameters exert the strongest influences on these communities. Preliminary results indicate that in overall bacteria are more abundant in soil than fungi and few sites have notably higher abundance of these microbes. In addition, we have detected some soil patameters which tend to have reduced the overall fungal abundance and enhanced the presence of arbuscular mycorrhizal fungi and N-fixing bacteria. More detailed information on the diversity and composition of soil microbial communities is expected from the high-throughput sequenced data

Diversity of arbuscular mycorrhizal fungi and its chemical drivers across dryland habitats

Qatar is largely characterized by a hyper-arid climate and low soil fertility which create a stressful soil environment for arbuscular mycorrhizal (AM) fungi. In a study of AM fungal communities and their relationship with soil chemical characteristics, we used a high-throughput sequencing technique to explore AM fungal diversity and community composition in different habitats across Qatar. We identified a total of 79 AM fungal taxa, over 77% of which were species from the Glomeraceae family. The lowest AM fungal diversity was observed in saltmarsh and in one rawdha site, while the highest richness, effective number of species, and diversity were observed in rawdha and sabkha communities. NMDS and multiple regression analyses showed that AM fungi were negatively correlated with soil pH and TC, but positively correlated with K and NO3−. AM fungi also were positively correlated with Cd, with the latter suggesting that very low levels of heavy metals may not always be harmful to AM fungi. These findings provide baseline information on AM fungal assemblages and the chemical drivers of diversity across communities in Qatar. This work partly compensates for the current lack of broad-scale studies in the Arabian Peninsula by providing understanding of overall patterns of AM fungi and their drivers in the region.- NMDS - This work was supported by a grant from Qatar Petroleum to JMA (QUEX-CAS-QP-RD-18/19)

Temperature and pH define the realised niche space of arbuscular mycorrhizal fungi

The arbuscular mycorrhizal (AM) fungi are a globally distributed group of soil organisms that play critical roles in ecosystem function. However, the ecological niches of individual AM fungal taxa are poorly understood. We collected > 300 soil samples from natural ecosystems worldwide and modelled the realised niches of AM fungal virtual taxa (VT; approximately species-level phylogroups). We found that environmental and spatial variables jointly explained VT distribution worldwide, with temperature and pH being the most important abiotic drivers, and spatial effects generally occurring at local to regional scales. While dispersal limitation could explain some variation in VT distribution, VT relative abundance was almost exclusively driven by environmental variables. Several environmental and spatial effects on VT distribution and relative abundance were correlated with phylogeny, indicating that closely related VT exhibit similar niche optima and widths. Major clades within the Glomeraceae exhibited distinct niche optima, Acaulosporaceae generally had niche optima in low pH and low temperature conditions, and Gigasporaceae generally had niche optima in high precipitation conditions. Identification of the realised niche space occupied by individual and phylogenetic groups of soil microbial taxa provides a basis for building detailed hypotheses about how soil communities respond to gradients and manipulation in ecosystems worldwide