Community structure of arbuscular mycorrhizal fungi in fluvial and maritime dunes of Brazilian Northeast

Arbuscular mycorrhizal fungi (AMF) are indispensable for the establishment of plant communities, which is essential for the stabilization of sediments in ecosystems, such as sand dunes. This study aimed at assessing the diversity and distribution of AMF in fluvial and maritime dunes, in order to verify if AMF community structure is influenced by physical and chemical soil characteristics. AMF species richness, diversity and community composition, spore density and mycorrhizal colonization were investigated in four natural dunes areas, i.e. two fluvial and two maritime dunes in Bahia State, northeastern Brazil. Soil samples were collected in September 2013 and March 2014. Spore density differed significantly among the dunes and sampling times, with the highest values recorded in the maritime dunes. Fifty-four AMF species were identified in the study areas, of which 51 were identified from field samples and three additional (Acaulospora longula, Acaulospora spinosa and Rhizoglomus natalense) after propagation in trap cultures. The most representative genera were Acaulospora (11), Glomus (10) and Gigaspora (8). Gigaspora margarita was the only species found in all areas at both sampling times. The AMF community composition significantly differed among the four dunes. There was a correlation between the AMF community composition and the soil characteristics. Highest species richness per sample was observed in the areas of maritime dunes. The fluvial and maritime dunes of Bahia showed high diversity of AMF and the soil is an important factor in the structure of the AMF community in sand dunes.