Abstract
The goal of this study was to gain insight into the diversity of culturable actinobacteria in desert soil crusts and to determine the physiological characteristics of the predominant actinobacterial group in these crusts. Culture-dependent method was employed to obtain actinobacterial strains from desert soil samples collected from Shapotou National Desert Ecological Reserve (NDER) located in Tengger Desert, China. A total of 376 actinobacterial strains were isolated and 16S rRNA gene sequences analysis indicated that these isolates belonged to 29 genera within 18 families, among which the members of the family Geodermatophilaceae were predominant. The combination of 16S rRNA gene information and the phenotypic data allowed these newly-isolated Geodermatophilaceae members to be classified into 33 “species clusters,” 11 of which represented hitherto unrecognized species. Fermentation broths from 19.7% of the isolated strains showed activity in at least one of the six screens for antibiotic activity. These isolates exhibited bio-diversity in enzymatic characteristics and carbon utilization profiles. The physiological characteristics of the isolates from different types of crusts or bare sand samples were specific to their respective micro-ecological environments. Our study revealed that members of the family Geodermatophilaceae were ubiquitous, abundant, and diverse in Shapotou NDER, and these strains may represent a new major group of potential functional actinobacteria in desert soil.
Highlights
It has become increasingly clear that the overuse of antibiotics and the subsequent rise in antibioticresistant pathogens will force us to search for new antibiotics to meet urgent clinical needs (Talbot et al, 2006)
The 16S rRNA gene sequences revealed that 376 actinobacterial strains were isolated from the 50 samples
The family Geodermatophilaceae consists of three genera: Geodermatophilus, Blastococcus, and Modestobacter, that includes 25 validly described species
Summary
It has become increasingly clear that the overuse of antibiotics and the subsequent rise in antibioticresistant pathogens will force us to search for new antibiotics to meet urgent clinical needs (Talbot et al, 2006). The Shapotou desert region (latitude 36◦39′-37◦41′N, elevation 104◦25′-105◦40′E) is recognized as the first “National Desert Ecological Reserve” (NDER) in China This NDER is renowned worldwide as a teaching and scientific research base for studying controlled desertification. It is Ubiquity, diversity and physiological characteristics of Geodermatophilaceae located on the southeast edge of the Tengger Desert, south of the Yellow River, in the northwest part of China. This region is at an altitude of 1300–1700 m, has an annual average precipitation of 186.2 mm, an annual mean temperature of 9.7◦C, and an annual average wind speed of 2.8 m/s with a typical temperate desert climate
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