Bacterial diversity of bryophyte-dominant biological soil crusts and associated mites

We surveyed bacterial communities in arid land bryophytic soil crusts (BSCs) and in three associated mite species (a tydeid, a neonanorchestid, and an oribatid) using 16S rRNA gene libraries. We compared these to cyanobacterial crust systems and soils. We found 11 major phyla and 7 candidate phyla, and for both crusts and mites the dominant phyla were Bacteroidetes, Acidobacteria, and Proteobacteria. Of the 330 unique 16S rRNA gene sequences found (97% nucleotide identity), mites and crusts shared only 20. Bacteroidetes were prevalent in crust libraries, suggesting the bacterial community in bryophytic crusts was affected by high carbon availability. Acidobacteria were most prevalent in mites. We also found sequences associated with plant rhizospheres, such as members of the order Rhizobiales, and the family Oxalobacteraceae. Mite libraries contained 7 novel sequences that grouped with Rickettsiella, an obligate intracellular arthropod pathogen, as well as bacterial groups related to beetle gut bacteria and known symbionts in Tetraponera ants. Bacterial communities in bryophytic BSCs differed from those reported for cyanobacterial BSCs and soils. (C) 2012 Elsevier Ltd. All rights reserved.