a b s t r a c tCyanobacteria have received much attention in soil due to their nitrogen-fixing ability and significant contribution in primary production. The diversity and distribution of unexplored cyanobacteria of Chhattisgarh has been investigated. We attempted to isolate, identify, and characterize the different cyanobacterial strains from different unexplored sites of Chhattisgarh. Twenty-nine strains of cyanobacteria, comprising two unicellular, four colonial, nine unbranched nonheterocystous, 12 unbranched heterocystous, and two pseudobranched cyanobacteria were phenotypically characterized on the basis of microscopic observation, that is, cell width, cell length, average filament length, colonial diameter, and position, shape and dimensions of heterocysts and akinetes. Results suggested that the phenotypic attributes were strain specific. Principle component analysis of heterocystous and nonheterocystous strains proved that environmental factors and physicochemical properties cumulatively decided the structure and distribution of cyanobacteria. These approaches also uncovered cyanobacterial diversity, which help in studying molecular diversity and documentation of unexplored cyanobacteria of Chhattisgarh, India.

Filamentous cyanobacterium (strain 10C-PS) isolated from a fresh water body of Bilaspur, Chhattisgarh, India is being described as new species of the polyphyletic genus Scytonema. Phenotypic, molecular and phylogenetic characterization was performed and the combined results validated the strain as a new species. Careful observations of the filaments, presence of a distinctly textured sheath throughout the length of the trichome, differences in the shape and dimensions of the vegetative cells, and heterocytes provided reliable morphological signals that the strain differed from rest of the closely related species. Sequencing of the 16S rRNA gene showed 96.89% sequence similarity with Scytonema hofmanni PCC 7110 while rbcl and psbA sequencing showed 95% and 92% similarities with Scytonema hofmanni PCC 7110 and Nostoc sp. PCC 7524 respectively while the nifD gene sequence similarity was found to be 96% with Scytonema hofmanni PCC 7110. The PC-IGS region was sequenced and concatenated cpcB, IGS and cpcA regions indicated 97% closest similarity with Scytonema sp. PCC 7110 and Scytonema bohnerii Ind24. Subsequent phylogenetic analyses gave a strong pattern of distinct clustering in case of all the molecular markers. The phenotypic, genetic and phylogenetic observations prove conclusively that the strain 10C-PS is a new species in the genus Scytonema with the name proposed being Scytonema bilaspurensis.Key words: 16S rRNA, cpcB, cyanobacterium, IGS and cpcA, phylogeny, psbA gene, rbcl gene, Scytonema bilaspurensis.A long evolutionary history, morphological intricacies and culturing problems have made cyanobacterial taxonomy, an exhaustive but interesting field of study. Advent of quality sequence data and phylogenetic approaches have helped in providing a better resolution of cyanobacterial phylogeny and evolution. Substantial taxonomic assignments of the recent years (Anagnostidis & Kom arek, 1985, 1988, 1990Kom arek & Anagnostidis, 1986, 1989B€ udel & Kauff, 2012) have helped in developing a better understanding of cyanobacterial systematics. The recent, S€ ußwasserflora series on the cyanoprokaryotes (cyanobacteria) has been shaped up to accommodate both morphological and genotypic data in congruence along with supporting more revisionary work in terms of discovering new genera and species (Kom arek, 2013). Kom arek et al. (2014) have placed the genus Scytonema in the family Scytonemataceae of the order Nostocales. As per the recent S€ ußwasserflora series it is well established that this group is indeed a species-rich group of isopolar, falsebranching heterocytous cyanobacteria. This group has also been revised through a polyphasic approach and hence, taxonomic changes can be expected. Initial investigations of some of the workers (Fiore et al., 2007;Aguiar et al., 2008;Sant'anna et al., 2011;Vaccarino & Johansen, 2011; Becerra-Absal on et al., 2013; Kom arek, 2013) have shown that at least the genera Scytonema and Brasilonema form a monophyletic clade, based on a 16S rRNA data analysis. Some of the definin...

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Cyanobacteria are among those tremendous microbial community that adds both aesthetic and ethnic value to the nature. They majorly contribute as a primary producer via photosynthesis due to the presence of various photosynthetic pigments (chlorophyll a, carotenoids, and phycobillisomes) and nitrogen fixation. Apart from this, cyanobacteria also work differently from the league because they bear enormous plasticity in their nature and can survive in the most extreme situations such as saline, thermocline environment, metal and heavy metal prone environment, etc. Iron, one of the second most abundant metal, third most limiting nutrient and fourth most abundant trace element that achieves equal position to that of macro element because of its contribution in all the vital life supporting activities such as photosynthesis, nitrogen fixation and electron transport chain mechanism. The availability and unavailability of iron leads to production of ROS within the cell which is directly linked to an oxidative stress via Haber weiss reaction and Fentons mechanism. So to assess the iron induced stress in cyanobacteria, soils from different locations of Chhattisgarh, have been tested for iron concentration by using Atomic Absorbtion Spectrophotometry (AAS). Then, number of cyanobacterial species was isolated from Turkadih, Bilaspur, and Chhattisgarh having highest iron concentration (140 ppm). They were treated with different concentrations of iron (0, 20, 50, 75, 100, 150 and 200 µM FeCl3). Result suggested that only Anabaena sphaerica a filamentous, heterocystous cyanobacterium could survive up to 100 µM FeCl3 (5 times higher concentration as is used for standard growth medium) and rest of the concentrations were found to be lethal for all the cyanobacterial species. The alterations in morphological, physiological and biochemical attributes were assessed and investigated. Further, proteome analysis (2D-Gel Electrophoresis) of A. sphaerica suggested that some unique proteins need proper investigation via MALDI-TOF. Concisely, it can be said that this part of research creates an interest to investigate at higher and advanced level for the most iron tolerant species isolated from the iron enriched region of Chhattisgarh.

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