| Congresso Brasileiro de Microbiologia 2023 | Resumo: 819-1 | ||||
Resumo:Cyanobacteria belonging to the order Nostocales are phototrophic bacteria capable of fixing
atmospheric nitrogen, which plays a crucial role in aquatic and terrestrial biogeochemical cycles.
Members of this order are known for their ability to synthesize a diverse range of specialized
metabolites of biotechnological interest, with several genera forming blooms in aquatic
environments. More than 1600 secondary metabolites are reported in 90 genera of
cyanobacteria, where two-thirds of these natural products were manufactured by members of
the genera Lyngbya, Microcystis, Nostoc, and Hapalosiphon. This genus belongs to the order
Nostocales and contains natural products of great importance, such as tricamides,
viridismamides, anacyclamides, and prochlorosines. This study aimed to conduct genomic
analyses of six cyanobacterial strains that belonged to the order Nostocales and were isolated
from various environments in Brazil. To unravel this potential for the production of specialized
metabolites by these strains, the genomes were sequenced and assembled. For this, genomic
libraries of the strains were constructed and the sequencing was performed on the
MiSeq(Illumina), HiSeq (Illumina), PacBio HiFi, and Nanopore Mini Ion platforms. Genomes
were assembled independently and by reference. From the generated genomes, the prediction
and annotation of genes were made, through available computational tools (antiSMASH and
BiG-SCAPE). The genomes had an average of 166 contigs, but this was expected due to the
characteristics of cyanobacterial genomes, which have many homopolymeric regions. Despite
the amount of contigs, the other quality parameters were excellent with great genome
completeness and low contamination rate. In the case of Komarekiella atlantica CCIBt3483, the
sequencing was performed using the PacBio HiFi, which allowed closing of the genome,
keeping it in only one scaffold, with excellent completeness and low contamination rate.
Functional annotation using antiSMASH identified a few secondary metabolites, being the main
one Rhizomide in Dendronalium phyllosphericum CENA369, with the most similar presenting
only 50% of sequence coverage. The use of BIG-SCAPE to predict BGCs showed a total of 128
BGCs and demonstrated that most of them are unknown. The sequencing and assembly
methodologies used in this work proved efficient for obtaining high-quality genomes. The
potential for producing secondary metabolites using automatic prediction tools did not show high
identity to those in the database. Still, the prediction analysis showed great potential to
synthesize unknown compounds. Therefore, it is necessary to develop metabolomic studies to
reveal these yet to be discovered metabolites. Palavras-chave: Cyanobacteria, Genomic analysis, Specialized metabolites, Nostocales, prediction Agência de fomento:CAPES | |||||