Isolation of a Mesophilic and Halotolerant Strain of Kocuriapolaris From Gandom Beryan Area in the Lut Desert of Iran, Moderately Resistant to Gamma Radiation and Desiccation

Mohammad Sadegh Shirsalimian¹, Abbas Akhavan Sepahy^1*, Mohammad Ali Amoozegar², Seyed Mehdi Kalantar³ and Reza Dabbagh⁴

¹Department of Microbiology, Faculty of Biological Sciences, Islamic Azad University North Tehran Branch, Tehran, IR Iran.

²Extremophiles Laboratory, Department of Microbiology, Faculty of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, IR Iran.

³Genetics Department, Shahid Sadoughi University of Medical Sciences, Yazd, IR Iran.

⁴Nuclear Sciences and Technology Research Institute, NFCS, Tehran, IR Iran.

Corresponding Author E-mail: bioshk@yahoo.com

DOI : http://dx.doi.org/10.13005/bbra/2404

ABSTRACT: Despite the extreme environmental conditions, hot arid deserts have a number of microhabitats that allow the evolution of unique extremophiles so as to being adapted to desiccation and ionizing radiation. There have been several attempts to demonstrate a link between radiation resistance and desiccation tolerance phenotypes. The diversity of ionizing radiation resistant bacteria was investigated in soil and surface sand samples collected from arid Gandom Beryan area located in the Lut desert in Iran, by exposing to different periods of dehydration in a desiccator. The surviving bacteria were recovered after plating on R2A, TSA and TGY agar media. After discarding the spore-forming isolates; Twelve orange, pink, yellow and white pigmented colonies forming Gram-positive cocci-shaped were obtained. The isolated strains on R2A agar were more diverse (9 isolates) compared with those on TSA (3 isolates) and TGY (without any isolates). A gamma radiation and desiccation resistant, coccoid Gram-positive, lemon-yellow to pale-orange pigmented actinobacterium, designated strain A10, was isolated from a mixture of sand samples. Morphological and Biochemical characteristics and phylogenetic analysis based on 16S rRNA gene sequences revealed that strain A10 belonged to the genus Kocuria and was closely related to Kocuriapolaris CMS 76orT (99.4 % similarity). Strain A10 was shown to be resistant to gamma radiation up to 4 kGy and remained viable after desiccation for 28 days.

KEYWORDS: Mesophilic; Halotolerant; Kocuriapolaris; Lut Desert; Iran

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