Compartmentalization of endophytic communities associated with halophytes from two separate locations on the island of Mallorca and the influence of the rhizosphere on the endosphere. Endophytic communities associated with halophytes

In the present study, the microbial community structures of the endosphere of the halophyte Arthrocnemum macrostachyum were evaluated from two locations in Mallorca, Spain, focusing on three plant compartments (roots, green and red stems) compared to the rhizospheric soil where the plants grew. The physicochemical parameters of the rhizospheric soils differed between locations, and they were characterized by different microbial community structures. Accordingly, the endophytic community structures, mainly composed of putatively halophilic organisms, were highly influenced by the rhizospheric soil microbiota, as revealed by the co-occurrence of major endophytic taxa exclusive to the plant location. Moreover, the reduction of diversity from the endorhizosphere towards the red leaves reinforced the evidence that the colonization of the plant by bacteria occurred from the rhizospheric soils through the roots and subsequent migration to the aerial parts of the plant. Finally, there were certain relevant ubiquitous taxa, such as Chromohalobacter canadensis, Rudaea cellulosilytica (never reported before as endophytic), Psychrobacter sp., Bradyrhizobium sp. and Halomonas sp., that seemed to have a direct specific relationship with the plants. Some of these relevant endophytes were not always detectable in their respective soils, and were probably part of the soils’ rare biosphere, which would gain preponderance in a favorable endophytic environment.