Morphometric Characterization of Endomycorrhizal Fungi (Glomeraceae and Acaulosporaceae) from the Bouaflé and Niellé Areas in Côte d'Ivoire

Abstract

Mycorrhizal symbioses, which are widespread in various terrestrial ecosystems, constitute a very important research topic for many biologists. Arbuscular mycorrhizal fungi (AMF), belonging to the phylum Glomeromycota, take their name from their characteristic structures: arbuscules. Spores represent the main structures allowing the morphological identification and characterization of AMF. The spores directly extracted from soil samples were identified under an optical microscope. The diversity of AMF in maize rhizospheres in Bouaflé and Niellé areas was highlighted. Thus, 12 genera of AMF divided into 8 families have been identified. Spores of two families of endomycorrhizae (Glomeraceae and Acaulosporaceae) have been described. The spores of the Glomeraceae family represented by 4 genera <i>Glomus</i>, <i>Funneliformis</i>, <i>Septoglomus</i> and <i>Rhizophagus</i> are globose to subglobose, 45 to 200 µm in size. The spores have a single wall composed of 3 to 4 parietal layers. The outer layers stain with Melzer's reagent. The suspensory hypha often characterized by the presence of constriction, light brown in color is the extension of layer 2. Morphologically, the spores of Acaulosporaceae represented by a single genus <i>Acaulospora</i>, are distinguished by the globose to subglobose shape. The spores are whitish, pale yellow, golden yellow to orange-brown in color and 90 to 200µm in diameter. The subcellular structure of spores consists of a spore wall (outer wall) and two inner walls. The outer and inner walls of the spores consist of three parietal layers. The outermost layers are evanescent, hyaline whitish, orange-brown to pale yellow. The layers of the inner wall are adherent to each other appearing as a single layer. The surface of the spores, populated with projections of different shapes resembling often rudimentary hyphae, show scars and ornamentations. This study gives the essential of the status of AMF and revealed the morphometric and structural characteristics of some AMF.