Species Richness of Arbuscular Mycorrhizal Fungi in Heterogenous Saline Environments

Sabkha (inland and coastal—saline beds or saline lands) are widespread in Saudi Arabia and are distinguished by their hypersaline nature. These hypersaline habitats are commonly covered by halophytic vegetation. Moreover, Arbuscular mycorrhizal fungi (AMF) are an essential component of these habitats and exhibit a unique adaptation and contribute significantly to ecosystem variability, diversity, and function. Additionally, AMF from saline habitats are an essential component for the successful rehabilitation of salinity-affected areas. Despite their importance, little is known about the distribution and abundance of AMF along inland and coastal sabkhat of Saudi Arabia. Therefore, the main objective of this study was to investigate the abundance and diversity of AMF in the coastal and inland sabkhat of Saudi Arabia. Five soil samples, each from five randomly selected spots (considering the presence of dominant and co-dominant halophytic species), were collected from every location and were used to assess the AMF abundance and diversity. The study indicated that the highest number of AMF spores was recorded from Jouf, averaging ≈ 346 spores 100 g−1 dry soil, and the lowest from Uqair, averaging ≈ 96 spores 100 g−1 dry soil. A total of 25 AMF species were identified, belonging to eight identified genera viz., Acaulospora, Diversispora, Gigaspora, Scutellospora, Claroideoglomus, Funneliformis, Glomus, and Rhizophagus and five families. Of the total identified species, 52% belonged to the family Glomeraceae. Moreover, the highest number of species was isolated from the sabkha in Qasab. Additionally, Glomeraceae was abundant in all the studied locations with the highest relative abundance in Uqair (48.34%). AMF species Claroideoglomus etunicatum, Funneliformis mosseae, Glomus ambisporum, and Rhizophagus intraradices were the most frequently isolated species from all the Sabkha locations with isolation frequency (IF) ≥ 60%, and Claroideoglomus etunicatum (Ivi ≥ 50%) was the dominant species in all the studied locations. Furthermore, data on the Shannon–Wiener diversity index showed that the highest AMF species diversity was in Qaseem and Qasab habitats. The highest Pielou’s evenness index was recorded in Jouf. Moreover, the soil parameters that positively affected the diversity of identified species included Clay%, Silt%, HCO31−, OM, MC, N, and P, while some soil parameters such as EC, Na+, SO42−, and Sand% had a significant negative correlation with the isolated AMF species. This study revealed that AMF can adapt and survive the harshest environments, such as hypersaline sabkhas, and thus can prove to be a vital component in the potential restoration of salinity-inflicted/degraded ecosystems.