| Summary: | Plant-associated microbes could play a role in plant colonization of sand dune ecosystems, but microbes associated with plants colonizing those ecosystems in the arctic are poorly known. I characterized Deschampsia flexuosa-associated microbiomes in two successional stages (early and late) of arctic inland sand dune differ in their plant species richness and soil physiochemical properties. The work based on culturable microbes showed that different plant parts harbour generalist and specific groups of endosphere microbes and most of the endosphere bacteria were closely related to other cold habitat microbes. Also, most of the endosphere bacteria possessed an important plant growth promoting property of solubilizing organic phosphate. Next generation sequencing methods showed that endosphere microbial species richness was determined by soil characteristics (succession) and plant compartment. Successional stage strongly affected the microbial community composition. Further, reciprocal transplantation experiment showed that endosphere microbial species richness was determined by successional stage rather than transplantation type (self or reciprocal). Irrespective of successional stage, after reciprocal transplantation microbial community compositions in most of the leaf and root compartments differed from local non-transplanted control. In contrast, the microbial community composition only in few root compartments was affected by self-transplantation. Further, leaf endosphere bacterial community composition was significantly affected by arbuscular mycorrhizal fungal (AMF) inoculation under greenhouse conditions. Overall, my work provided data from poorly characterized arctic biota and novel insight into endosphere bacterial and fungal community assemblage in arctic inland sand dune ecosystem. These results could be utilized when restoring vegetation in sand dunes and similar extreme ecosystems.
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