Ionizing-radiation-resistant Kocuria rhizophila PT10 isolated from the Tunisian Sahara xerophyte Panicum turgidum: Polyphasic characterization and proteogenomic arsenal

14 páginas, 5 tablas, 4 figuras
A new strain belonging to the genus Kocuria, designed PT10, was isolated from irradiated roots of the xerophyte Panicum turgidum. Isolate PT10 is a Gram-positive, coccoid, aerobic and ionizing-radiation (IR)-resistant acti-nobacterium. PT10 has shown an ability to survive under extreme conditions, such as gamma irradiation, desiccation and high concentration of hydrogen peroxide. Phenotypic, chemotaxonomic and comparative genome analyses support the assignment of strain PT10 (LMG 31102 =DSM 108617) as Kocuria rhizophila. The complete genome sequence of PT10 consists of one chromosome (2,656,287 bps), with a 70.7% G +C content and comprises 2481 protein-coding sequences. A total of 1487 proteins were identified by LC-MS/MS profiling. In silico analyses revealed that the proteome of the oxidation-tolerant PT10 possesses several features explaining its IR-resistant phenotype and many adaptive pathways implicated in response to environmental pressures — desiccation, cold, reactive oxygen species and other stressors.
This work was performed under the auspices of Université Lyon 1, UMR 5557, Ecologie Microbienne (France) and the National Center for Nuclear Sciences and Technologies CNSTN (MESRS, Tunisia) and in the ambit of the BIODESERT research program of the LR11-ES31 (BVBGR, ISBST, University of Manouba (MESRS, Tunisia). The LABGeM (CEA/ Genoscope & CNRS UMR8030), the France G ́enomique and French Bioinformatics Institute national infrastructures (funded as part of Investissement d’Avenir program managed by Agence Nationale pour la Recherche, contracts ANR-10-INBS-09 and ANR-11-INBS-0013) are acknowledged for support within the MicroScope annotation platform. We thank Betty Bigai, Corinne Sannaire and platform Genomique Environnementale PGE, UMR CNRS 5557 for technical support