Rhizophagus clarus (previously known as Glomus clarum[1]) is an arbuscular mycorrhizal fungus in the family Glomeraceae. The species has been shown to improve nutrient absorption and growth in several agricultural crops but is not typically applied commercially.[2]
Distribution and conservation
Rhizophagus clarus is widely distributed and found worldwide.[3] The species is proposed to be at the level of Least Concern on the IUCN Red List due to its global distribution.[4]
Spores and morphology
The spores of Rhizophagus clarus vary in color from white to yellow-brown.[5][6][7] They naturally vary in size from 100 to 260 μm and are globose to subglobose in shape.[5][6] The spores are larger than the spores of other species in the genus Rhizophagus.[8] The spores are composed of an outer mucilaginous layer which thickens as they mature.[6][8]
Rhizophagus clarus is composed of extraradical hyphae that extend past the rhizosphere soil zone, and intraradical hyphae that inhabit the host plant's roots.[9]
Ecology
Rhizophagus clarus is a biotrophic mutualist fungus that exchanges soil nutrients with its host plant for photoassimilates.[10]
Rhizophagus clarus is able to form a symbiotic relationship with a wide variety of plant hosts, some of which include:
Rhizophagus clarus has a relatively small number of genes coding for cell wall degrading enzymes because the species is mutualistic and not pathogenic.[8]Effector molecules secreted by the fungus affect plant signaling and immune function to promote fungal colonization.[10] Hyphal anastomosis is common in colonies of Rhizophagus clarus and allows for horizontal gene transfer and increased variation in genotypes.[9]
