Survey of Microorganisms’ World in Kerman Desert

Microorganisms have a crucial role in soil processes. Information about soil microbiota in arid and semiarid area, especially in Iran is limited. The aim of study was to determine microbial diversity of soil biological crusts (SBC) of Khabr and Ruchun National Park. First, microorganisms of SBC were identified through culturedependent and culture-independent techniques. Then, microbial diversity was tested by Next Generation Sequencing (NGS) technique. After that, nitrogenase activity of the isolated Cyanobacteria strains was determined via acetylene reduction and expression of nifH gene by using real time-PCR. Next, desiccation stress was performed on the isolated Cyanobacteria and the superior strain was selected. Whole genome of the tolerance strain of Cyanobacteria to the desiccation stress was sequenced. Afterward, its transcriptional response to the desiccation stress was assayed. Finally, by lab modelling of the desert soil inoculated with the selected Cyanobacteria concerning to the nitrogen fixation, the growth of model plant was evaluated. The results indicated that this area has vast diversity of different phylum of microorganisms. Furthermore, changes in the composition of microbial communities due to the climate fluctuations or other stresses can be shown before any changes in chemical and biochemical properties of soil. The soil treated with Cyanobacteria especially when accompanied with chemical fertilizer showed well increasing of model plant growth and improving soilproperties as well. The comparative genome analysis showed the presence of genes involved in the biosynthesis of mycosporines, trehalose and phycobilisome. Transcriptomics and comparative genome analysis showed that ۳۹۷ genes such as genes encoding catalase and chaperons were differentially expressed in response to thedesiccation stress. Transcriptomics and comparative genomic studies can open a new window to the adaptation mechanisms of cyanobacteria studies in terrestrial ecosystems.

کلیدواژه ها:

Cyanobacteria ، Acetylene Reduction ، Real Time-PCR ، Nitrogenase Activity ، nifH ، Khabr and Ruchun Park