Unravelling the community of arbuscular mycorrhizal fungi associated with endemic plants from a neotropical dry forest

Abstract

Arbuscular mycorrhizal fungi form symbiotic associations with 80% of all known plants, allowing the fungi to acquire plant-synthesized carbon, and confer an increased capacity for nutrient uptake by plants, improving tolerance to abiotic and biotic stresses. We aimed to characterize the mycorrhizal community associated with Neoglaziovia variegata (so-called `caroa`) and Tripogonella spicata (so-called resurrection plant) using high-throughput sequencing of the partial 18S rRNA gene. Both endemic plants to neotropical dry forests and shrubland ecosystems were sampled in the Caatinga biome, located in northeastern Brazil. Illumina MiSeq sequencing of 37 rhizosphere samples (19 for N. variegata and 18 for T. spicata) revealed a distinct mycorrhizal community between the studied plants. There is a lack of information regarding the mycorrhizal composition of these plants, as revealed by our systematic review. According to alpha diversity analyses, T. spicata showed the highest richness and diversity based on the Observed ASVs and Shannon index, respectively. The four most abundant genera (higher than 10%) found were Glomus, Gigaspora, Acaulospora, and Rhizophagus, with Glomus being the most abundant in both plants. Nonetheless, Gigaspora, Diversispora, and Ambispora were specific for N. variegata, whilst Rhizophagus, Paraglomus, and Archaeospora were only associated with T. spicata. Therefore, the arbuscular mycorrhizal fungi community showed a genus-specific niche, and hence they may be differentially assisting the plants in the harsh environment of the Caatinga biome.