Is there symbiosis between a green algae of the genus Chara L. (Characeae) and Arbuscular Mycorrhizal Fungi (Glomeromycota)?
AMF diversity; ancestral soil fungi; lotic ecosystems; macroalgae; stoneworts.
The evolutionary history of plants suggests that green algae gave rise to vascular plants, whose radiation through terrestrial ecosystems occurred together with symbiotic fungi recognized for forming arbuscular mycorrhiza (AM). However, AM symbiosis in early divergent lineages of green algae such Charophyta has not been investigated. Therefore, we investigate the presence of colonization by AMF in populations of Chara from five Brazilian lotic environments. Additionally, we investigated the AMF species inhabiting the rhizosphere of Chara and the influence of edaphic properties on AMF occurrence. Twenty-five AMF species were detected in the rhizosphere of Chara sp., mainly from the Acaulosporaceae (11) and Glomeraceae (8) families. The rivers showed low AMF species richness with Rio do Gozo (16), followed by Una (8), Pratinha (2), Cuitegí (2) and Pandeiros (1), respectively. Nonetheless, none of the rhizoid fragments of Chara sp. obtained from tropical lotic environments showed colonization by AMF. Despite the occurrence of AMF species in rhizospheric sediments there is no mycorrhizal colonization in Chara sp. under the field conditions analyzed.