Characterization of bacterial communities in lithobionts and soil niches from Victoria Valley, Antarctica

• Published in: FEMS Microbiology Ecology
• Main Authors: Van Goethem, MW, Makhalanyane, TP, Valverde, A, Cary, SC, Cowan, DA
• Format: Article in Journal/Newspaper
• Language: English
• Published: eScholarship, University of California 2016
• Subjects: Victoria Valley; Antarc*; Antarctica
• Online Access: http://www.escholarship.org/uc/item/33v85617

Here we provide the first exploration of microbial diversity from three distinct Victoria Valley edaphic habitats, namely lithobionts (hypoliths, endoliths) and surface soils. Using a combination of terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene amplicon pyrosequencing we assess community structure and diversity patterns, respectively. Our analysis revealed that habitat type (endolithic vs hypolithic vs surface soils) significantly influenced bacterial community composition, even though dominant phyla such as Actinobacteria (41% of total reads) were common to all samples. Consistent with previous surveys in other Dry Valley ecosystems, we found that lithobionts were colonised by a few highly-dominant phylotypes (such as Gemmatimonas and Leptolyngbya). Our analyses also show that soil bacteria were more diverse and evenly distributed than initially expected based on previous evidence. In contrast to total bacteria, the distribution of Cyanobacteria was not strongly influenced by habitat type, although soil- and endolith-specific cyanobacterial lineages were found. The detection of cyanobacterial lineages in these habitats appears to be influenced by the dispersal of aquatic inocula from lacustrine communities or benthic mats which are abundant in Victoria Valley. Together, our results provide insights into the phylogenetic variation and community structure across niche habitats in Victoria Valley.