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Salt Tolerance and Polyphyly in the Cyanobacterium Chroococcidiopsis (Pleurocapsales)1Chroococcidiopsis Geitler (Geitler 1933) is a genus of cyanobacteria containing desiccation and radiation resistant species. Members of the genus live in habitats ranging from hot and cold deserts to fresh and saltwater environments. Morphology and cell division pattern have historically been used to define the genus. To better understand the genetic and phenotypic diversity of the genus, 15 species were selected that had been previously isolated from different locations, including salt and freshwater environments. Four markers were sequenced from these 15 species, the 16S rRNA, rbcL, desC1 and gltX genes. Phylogenetic trees were generated which identified two distinct clades, a salt-tolerant clade and a freshwater clade. This study demonstrates that the genus is polyphyletic based on saltwater and freshwater phenotypes. To understand the resistance to salt in more details, species were grown on a range of sea salt concentrations which demonstrated that the freshwater species were salt-intolerant whilst the saltwater species required salt for growth. This study shows an increased resolution of the phylogeny of Chroococcidiopsis and provides further evidence that the genus is polyphyletic and should be reclassified to improve clarity in the literature.
Document ID
20140008844
Document Type
Preprint (Draft being sent to journal)
Authors
Cumbers, John Robert
(California Univ. Santa Cruz, CA, United States)
Rothschild, Lynn J.
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
July 9, 2014
Publication Date
January 1, 2014
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
ARC-E-DAA-TN13481
Funding Number(s)
CONTRACT_GRANT: NAS2-02090
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Genus
Species
Salt Environments

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