Abstract:
Deserts in general, and Indian deserts in particular, are less attended for microbial
diversity. The Little Rann of Kutch (LRK), a coastal saline desert, is characterized by a
unique combination of both dry and wet features. This study represents the first report on
the extensive isolation, spatial distribution, 16S rRNA gene-based phylogeny, and
identification of novel taxa. A total of 87 isolates were obtained from three different
study sites in LRK. Based on the full 16S rRNA gene sequences, the isolates were
grouped into 44 different phylotypes of four phyla: Firmicutes, Proteobacteria,
Actinobacteria, and Euryarchaeota. These in turn were represented by 19 different
genera. Halomonas, Gracilibacillus, Thalassobacillus, Piscibacillus, Salimicrobium,
Alkalibacillus, Bhargavaea, Proteus, Marinobacter, Pseudomonas, Kocuria,
Corynebacterium, Planococcus, Micrococcus and Natronococcus identified in this
study had never before been reported from this habitat. A majority of the isolates
displayed broad salt and pH tolerance. The bacterial diversity of Venasar and Jogad
closely resembled with each other. While Bacillus, Virgibacillus, Gracillibacillus, and
Bhargavaea were common genera in all sites, six putative novel taxa of different
phylogenetic groups were identified. Available nitrogen, pH, Organic carbon, TDS, and
EC were the main environmental variables affecting the microbial diversity. Analysis of the
geographical distribution revealed that a majority of the phylotypes had cosmopolitan
distribution, followed by the saline and marine distribution, while ∼13% were affiliated with
only LRK. The phylotypes associated with marine distribution decreased with increasing
distance from the Gulf of Kutch, suggesting their endemism to marine environments. The
study established the taxonomic novelty and prospects for the discovery of unique
products and metabolites
