A coastal sand dune in New Zealand reveals high arbuscular mycorrhizal fungal diversity

Arbuscular mycorrhizal fungi (AMF) are components of coastal dune ecosystems around the globe where they provide a range of benefits to plants. The diversity and structure of AMF communities within these ecosystems, however, are poorly known. This study presents the first report of an AMF community in a New Zealand dune. Root samples were collected from the grass Spinifex sericeus R. Br., which dominates dunes of the North Island of New Zealand, along a 90m transect at Anawhata Beach. Spores were also collected from here. The AMF community within the roots was surveyed using 454 sequencing of the SSU gene region. Spores were identified by their morphology, and sequenced. The 22 operational taxonomic units recognised following the high throughput sequencing formed a phylogenetically diverse community, including at least 7 genera across the Glomerales and Diversisporales, with an additional genus detected by the spore investigation. Some root and spore derived sequences generated close BLAST matches to AMF from distant countries while others represent previously unknown biodiversity. Spore morphology also suggests undescribed AMF are present. High diversity was found within the genera Rhizophagus and Racocetra, and within a clade with no matches to a described genus. Spatial heterogeneity was observed, with taxonomic composition changing over distances of only 30 m.