Characterization of phototrophic microorganisms and description of new cyanobacteria isolated from the saline-alkaline crater-lake Dziani Dzaha (Mayotte, Indian Ocean)

Abstract

The saline-alkaline crater-lake Dziani Dzaha (Mayotte, Indian Ocean) is dominated by the bloom-forming cyanobacterium Arthrospira. However, the rest of the phototrophic community remains underexplored because of their minute dimension or lower biomass. To characterize the phototrophic microorganisms living in this ecosystem considered as a modern analog of Precambrian environments, several strains were isolated from the water column and stromatolites and analyzed using the polyphasic approach. Based on morphological, ultrastructural and molecular (16S rRNA gene, 18S rRNA gene, 16S-23S internal transcribed spacer (ITS) region and cpcBA-IGS locus) methods, seven filamentous cyanobacteria and the prasinophyte Picocystis salinarum were identified. Two new genera and four new cyanobacteria species belonging to the orders Oscillatoriales (Desertifilum dzianense sp. nov.) and Synechococcales (Sodalinema komarekii gen. nov., sp. nov., Sodaleptolyngbya stromatolitii gen. nov., sp. nov. and Haloleptolyngbya elongata sp. nov.) were described. This approach also allowed to identify Arthrospira fusiformis with exclusively straight trichomes instead of the spirally coiled form commonly observed in the genus. This study evidenced the importance of using the polyphasic approach to solve the complex taxonomy of cyanobacteria and to study algal assemblages from unexplored ecosystems.

When Is A Lineage A Species? A Case Study In Myxacorys gen. nov. (Synechococcales: Cyanobacteria) With The Description of Two New Species From The Americas

“…Most taxonomists are at least somewhat pragmatic and want the means to recognize species again when they are sampled in the future. This has not stopped them from describing cryptic species, whether in cyanobacteria or eukaryotic algae (Marin et al 2003, Henley et al 2004, Kosmala et al 2007, 2009, Linton et al 2010, Fawley et al 2011, Fu c ıkov a et al 2012, Osorio-Santos et al 2014, Bohunick a et al 2015, Cai et al 2017, Cellamare et al 2018.…”

A bridge too far in naming species: a total evidence approach does not support recognition of four species in Desertifilum (Cyanobacteria)

“…Transmission electronic microscope (TEM) images were obtained in a JEOL model JEM-1200 EXII microscope at the Institute of Cellular Physiology UNAM following the protocol described in Gonz alez- Resendiz et al (2013). Morphological description and identification was done in accordance with new and traditional reference works (Kom arek and Anagnostidis 2005, Kom arek and Johansen 2015), along with additional studies that describe populations of oscillatorian species (Dadheech et al 2012, Cai et al 2017, Ha sler et al 2017, Struneck y et al 2017, Cellamare et al 2018.…”

“…Morphological characteristics for six sequenced strains of Desertifilum apart from the Mexican strain were compiled from the publications in which they were described or treated (Dadheech et al 2012, Bravakos et al 2016, Cai et al 2017, Sinetova et al 2017, Cellamare et al 2018. In some instances, the descriptions given were incomplete.…”

“…), and Desertifilum dzianense from a crater lake in Mayotte in the Madagascar Channel of the Indian Ocean (Cellamare et al. ).…”

“…The simple filamentous genus Desertifilum was originally described from India's Thar desert crusts with D. tharense as the type species (Dadheech et al 2012). Since then, three additional species have been described: Desertifilum fontinale from a warm spring in Kenya (Dadheech et al 2014), Desertifilum salkalinema from an alkaline pool in Zhejiang Province, China (Cai et al 2017), and Desertifilum dzianense from a crater lake in Mayotte in the Madagascar Channel of the Indian Ocean (Cellamare et al 2018).…”