Diversity of cyanobacteria in rice fields of western Odisha and their photosynthetic efficiency under high temperature stress

Abstract

The wide distribution and agro-economic importance of cyanobacteria, a group of newlinephotoautotrophic microorganisms are extensively investigated in recent years. newlineCyanobacteria have become one of the most valuable microorganisms for their immense newlinepotential to mitigate atmospheric carbon dioxide, as biofertilizer and maintaining soil newlinefertility, energy production, pharmaceuticals, and many more. Thus it is necessary to newlineidentify the indigenous cyanobacterial population and examine their diversity to simplify newlineour understanding of their distribution pattern. The present study was conducted to newlineimprove our understanding of the morphological diversity and phylogenetic relationships newlineamong the heterocytous cyanobacteria isolated from the paddy fields of Western Odisha. newlineAltogether, 70 soil samples were collected from or around the Sambalpur district of the newlineWestern part of Odisha. Soil samples were cultured in nitrogen-free BG11 medium. Fiftynine heterocytous cyanobacterial pure strains were isolated from these soil samples. Of newlinethese, 25 species belonging to 4 genera, i.e., Nostoc, Anabaena, Calothrix, and newlineHapalosiphon, were identified. Morphological identifications of each species were newlineconducted based on their described unique morphological characteristics, making them newlinedistinct from other isolates. Further, these 25 isolates were used for phylogenetic (partial newline16S rRNA sequence, SCoTs, and ISSRs) studies for taxonomic validation. In the present newlinefinding, the 16S rDNA sequence analyzed by the maximum likelihood method illustrated newlinethat the cyanobacterial strains belonging to order Nostocales are highly polyphyletic and newlineintermixed among the genera. The morphological flexibility and phylogenetic relationship newlineamong the 25 species revealed the intragenus and intraspecies heterogeneity. Even though newlinethe strain Hapalosiphon welwitschi belonging to order Stigonematale is monophyletic newlinewithin itself, both the orders are intermixed and do not form any separate clusters. newline