Nostocaceae e Scytonemataceae isoladas de raízes de macrófitas aquáticas

Abstract

Heterocytous cyanobacteria are nearly ubiquitous organisms, inhabiting a wide variety of environments across the Earth's crust. The organisms, classified within the order Nostocales, are characterized by the presence of heterocytes, specialized cells responsible for an exclusive and ecologically significant function: biological nitrogen fixation. This adaptation enables members of Nostocales to colonize nitrogen-poor environments and establish symbiotic associations with organisms from numerous branches of the tree of life. In this study, we present the morphological characterization and molecular identification of nine strains belonging to the families Nostocaceae and Scytonemataceae, deposited in the Filamentous Cyanobacteria Collection (CFC) of the Federal University of Lavras (UFLA). These strains were isolated from the roots of Pistia stratiotes L. and Salvinia auriculata Aubl. Morphological identification and characterization were performed through light microscopy observations supported by specialized taxonomic literature. For molecular identification, the 16S rRNA gene was employed as a molecular marker. Phylogenetic analyses were conducted using Bayesian inference implemented in MrBayes, generating one phylogenetic tree for each family investigated. Lineages were identified in genera derived from Nostoc Bornet & Flahault and a species of the genus Brasilonema Fiore et al. The lineage P6109 was identified as Cronbergia amazonensis Genuário et al.