ABSTRACT
Cyanobacterial strain PS4G was isolated from seepage soil sampled at Pachmarhi, Madhya Pradesh, India, and was characterized using a polyphasic approach. The results of morphological analysis showed that strain PS4G had unique morphological characteristics which were not observed in the other described species of the genus Fortiea. In the 16S rRNA gene phylogenetic analysis inferred using Bayesian inference, maximum-likelihood and neighbour-joining methods, strain PS4G clustered within the clade consisting of the members of the genus Fortiea. Furthermore, in the secondary structure analysis using the D1-D1' helix and BoxB regions of 16S-23S ITS, strain PS4G showed marked differences in comparison with other members of the genus Fortiea. Overall, the morphological, phylogenetic and folded 16S-23S ITS secondary structure examination indicated that strain PS4G represents a novel species of the genus Fortiea. In accordance with the International Code of Nomenclature of Algae, Fungi and Plants we describe a novel species of Fortiea with the name Fortiea necridiiformans sp. nov.
Subject(s)
Cyanobacteria/classification , Phylogeny , Soil Microbiology , Bacterial Typing Techniques , Base Composition , Cyanobacteria/isolation & purification , DNA, Bacterial/genetics , India , Nucleic Acid Conformation , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNAABSTRACT
A freshwater dwelling, tapering, heterocytous cyanobacterium (strain V13) was isolated from an oligotrophic pond in the Shrirampur taluka, Ahmednagar district of Maharashtra in India. Initial morphological examination indicated that strain V13 belonged to the genus Calothrix. Subsequent molecular and phylogenetic assessment based on 16S rRNA gene, led us to describe the freshwater/terrestrial clade of Calothrix strains without terminal hairs as a new genus Dulcicalothrix gen. nov., with the type species Dulcicalothrix necridiiformans sp. nov. (Strain V13) on the basis of the necridia forming ability of the strain. Also, the 16S-23S ITS secondary structure analysis clearly differentiated strain V13 from the other members of the clade. Past studies and the current state of knowledge makes it imperative to separate the groups Calothrix (marine/freshwater Calothrix), Macrochaete and Dulcicalothrix (freshwater/terrestrial Calothrix) into separate genera in accordance with the International Code of Nomenclature for Algae, Fungi and Plants. Robust phylogenetic evidence and previous reports strongly support the re-erection of the family Calotrichaceae distinct from the existing family Rivulariaceae.
Subject(s)
Cyanobacteria/classification , Cyanobacteria/genetics , Phylogeny , DNA, Ribosomal Spacer , Ecosystem , Nucleic Acid Conformation , Phenotype , RNA, Ribosomal, 16S/geneticsABSTRACT
Two Nostoc-like strains have been isolated, purified, cultured and identified on the basis of the polyphasic approach using morphological, ecological, molecular and phylogenetic methods. Both strains were found to have morphology similar to the genus Nostoc, but clustered strongly in a group distant from the Nostocsensu stricto clade. Further analysis, using the folded structures of the 16S-23S ITS region revealed strong differences from closely related members of the genus Nostoc. Distinct phylogenetic clustering and strong tree topologies using Bayesian inference, maximum-likelihood and maximum-parsimony methods indicated the need to revisit the taxonomy of the members of this particular clade with a clear need for giving a generic status distinct from the genus Nostoc. In accordance with the International Code of Nomenclature for Algae, Fungi and Plants, the name Desikacharya gen. nov. is proposed for the new genus along with the description of two new species, Desikacharya nostocoides sp. nov. and Desikacharya soli sp. nov., and reclassification of Nostoc thermotolerans to Desikacharya thermotolerans comb. nov.
Subject(s)
Cyanobacteria/classification , Phylogeny , Bacterial Typing Techniques , Base Composition , Bayes Theorem , DNA, Bacterial/genetics , Likelihood Functions , Nostoc/classification , RNA, Ribosomal, 16S/genetics , RNA, Ribosomal, 23S/genetics , Sequence Analysis, DNAABSTRACT
Three heterocytous cyanobacterial strains were isolated from different habitats of Central India, and initial morphological studies indicated them to be members of the genus Nostoc or other closely related genera. Subsequent studies using morphological, ecological, molecular and phylogenetic methods indicated the three strains to be new members of the genera Aliinostoc and Desmonostoc. Folding of the D1-D1' helix of the ITS region clearly differentiated the three strains from the other closely related strains, thus providing final indications of the strains being different and new additions to the genera Aliinostoc and Desmonostoc. In accordance with the International Code of Nomenclature for algae, fungi and plants, we establish three new species: Aliinostoc tiwarii sp. nov, Aliinostoc soli sp. nov. and Desmonostoc magnisporum sp. nov. along with reclassifying Nostoc punensis as Desmonostoc punense comb. nov.
Subject(s)
Cyanobacteria/classification , Nostoc/classification , Bacterial Typing Techniques , Cyanobacteria/genetics , Cyanobacteria/isolation & purification , DNA, Bacterial/genetics , Ecosystem , Fresh Water/microbiology , India , Nostoc/genetics , Nostoc/isolation & purification , PhylogenyABSTRACT
A false branching cyanobacterium (strain 10A1_PS) was isolated from a freshwater body of the Pachmarhi Biosphere Reserve, India and was characterised using the polyphasic approach. The detailed morphological examination indicated that the strain belonged to the complex genus Scytonema as it exhibited typical false branching character whose frequency increased with age of the culture. As the family Scytonemataceae and the genus Scytonema has been shown to be polyphyletic in many studies, we provide deep insights into the phylogenetic complexities within the family Scytonemataceae based on 16S rRNA gene phylogeny along with complete morphological, molecular and phylogenetic characterisation of the strain. The 16S rRNA gene phylogenetic tree inferred by Bayesian Inference, Neighbor-Joining and Maximum Parsimony methods showed that the strain clustered within the Scytonema sensu stricto clade. The phylogenetic distance and the positioning of the strain clearly indicated it to be different from other Scytonema species. Further analysis using rbcL phylogeny, folded secondary structures of the 16S-23S ITS, p-distance and percentage pairwise similarity matrix clearly distinguished the strain 10A1_PS from the other closely related species. In accordance with the International Code of Nomenclature for Algae, Fungi and Plants, we propose the name of the new species to be Scytonema pachmarhiense.
