New genera of thin homocyted cyanobacteria from Brazilian tropical and subtropical marine islands

ABSTRACT

Brazil’s Atlantic Ocean coast is approximately 7500 km long, with several coastal and oceanic islands. The cyanoflora of this area is not commonly included in published studies, resulting in an underestimated diversity. Here, we isolated and analysed through a polyphasic approach three strains of marine benthic homocyted cyanobacteria from Brazilian coastal islands with two distinct climates: ALCB 132761 and ALCB 132774 are from the tropics, and ALCB 132760 from the subtropics. These strains presented differences in their cell morphometry and presence/absence of sheath, but were similar in apical cell shape, colour, and form of the trichome. In the 16S rRNA phylogeny, Maximum likelihood (ML) and Bayesian posterior probability (PP) analyses placed our strains in two robust clades. We propose that Microlinema tropicalium gen. et sp. nov. (ALCB 132774) is placed in the Leptolyngbyaceae, and Insularia amadoi gen. et sp. nov. (ALCB 132761) and Salileptolyngbya insularis sp. nov. (ALCB 132760) in Pseudanabaenaceae. The 16S-23S Internal Transcribed Spacer (ITS) was used to reconstruct Box B and D1-D1’ secondary structures, which were treated as autapomorphic characters. The new thin homocyted benthic cyanobacterial taxa described here from marine coastal islands of Brazil help to disentangle the Leptolyngbyaceae and Pseudanabaenaceae.

HIGHLIGHTS

• •Polyphasic description of two new Brazilian genera Insularia and Microlinema.

• •Expansion of Salileptolyngbya: recognition of one species for the Atlantic Ocean.

• •Elucidation of benthic genera in the Leptolyngbyaceae and Pseudanabaenaceae.

KEYWORDS:

• 16S-23S rRNA
• Brazilian marine cyanoflora
• Leptolyngbya senso lato
• phylogenetic diversity
• polyphasic taxonomy

Acknowledgements

We would like to thank Dr Kelly Regina Batista Leite (Universidade Federal da Bahia, UFBA), Dr Lázaro Benedito da Silva (UFBA), Dr Moema Cortizo Bellintani (UFBA) and Dr Suzana Telles da Cunha Lima (UFBA) for the use of their laboratory facilities. We also thank Dr Marli Fátima Fiore and the MSc. Renata Beatriz Cruz (CENA/Universidade de São Paulo/Piracicaba) for the use of the laboratory facilities and assistance with molecular analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

V. Araújo: original draft, light microscopy, transmission and scanning electron microscopy, and genetic analysis; M. Santos: transmission and scanning electron microscopy, review and editing of the manuscript; A. Schnadelbach: phylogenetic data interpretation, review and editing of the manuscript; J. Nunes: provide the access to the strains, paper review and editing; T. Caires: morphological and phylogenetic data interpretation, review and editing of the manuscript.

Additional information

Funding

This study and the scholarship of the first author were supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [CAPES Finance code 001]. The Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) supported JMCN with the grant [no. 308542/2018-5].