Volcanic deserts and primary succession - when and how do mycorrhizal fungi participate?

Biology, genetics, and ecology of the cosmopolitan ectomycorrhizal ascomycete Cenococcum geophilum

The ascomycete Cenococcum geophilum is a cosmopolitan and ecologically significant ectomycorrhizal (ECM) fungus that forms symbiotic associations with diverse host plants worldwide. As the only known ECM species within the large class Dothideomycetes, C. geophilum exhibits several characteristics that distinguish it from other ECM fungi. This fungus significantly contributes to ecosystem stability and development as an early colonizer of primary forest succession. The capacity of this symbiont to rapidly colonize disturbed or newly formed environments promotes the development of conditions that support the growth of other plant species, thus playing a crucial role in the ecological progression and restoration of ecosystems. Several C. geophilum isolates are known to enhance the drought resistance of host plants, a trait that is becoming increasingly important in the context of climate change and frequent drought events. In this review, we examined genetic studies that have assessed the phylogenetic structure of C. geophilum populations and identified the genes associated with adaptation to environmental stress and symbiosis. The high genetic diversity of C. geophilum is particularly noteworthy, considering its putative asexual reproductive mode. Population genomic analyses have suggested that C. geophilum is not a single species but rather a species complex comprising multiple cryptic lineages. This genetic variability may contribute to its adaptability and extensive distribution across habitats from circumpolar to tropical biomes. These lineages exhibit potential host preferences, suggesting a degree of specialization within the complex. The nuclear genome of C. geophilum has been sequenced, providing valuable insights into the symbiont genetic traits. Notably, this genome encodes a large set of repeated sequences and effector-like small secreted proteins. Transcriptomics has been used to identify candidate genes related to symbiosis and adaptation to environmental stress. Additionally, we briefly discuss how C. geophilum offers potential for sustainable forestry practices by improving resilience to stress.

Diversity, Distribution, and applications of arbuscular mycorrhizal fungi in the Arabian Peninsula

Investigations of arbuscular mycorrhizal fungi (AMF) received extreme interests among scientist including agronomists and environmental scientists. This interest is linked to advantages provided by AMF in enhancing the nutrients of their hosts via improving photosynthetic pigments and antioxidant production. Further, it also positively alters the production of plant hormones. AMF through its associations with plants obtain carbon while in exchange, provide nutrients. AMF have been reported to improve the growth of Tageteserecta, Zea mays, Panicum turgidum, Arachis hypogaea, Triticum aestivum and others. This review further documented the occurrence, diversity, distribution, and agricultural applications of AMF species reported in the Arabian Peninsula. Overall, we documented 20 genera and 61 species of Glomeromycota in the Arabian Peninsula representing 46.51 % of genera and 17.88 % of species of AMF known so far. Funneliformis mosseae has found to be the most widely distributed species followed by Claroideoglomus etuicatum. There are 35 research articles focused on Arabian Peninsula where the stress conditions like drought, salinity and pollutants are prevailed. Only one group studied the influence of AMF on disease resistance, while salinity, drought, and cadmium stresses were investigated in 18, 6, and 4 investigations, respectively. The genus Glomus was the focus of most studies. The conducted research in the Arabian Peninsula is not enough to understand AMF taxonomy and their functional role in plant growth. Expanding the scope of detection of AMF, especially in coastal areas is essential. Future studies on biodiversity of AMF are essential.