PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF Flavobacterium spp. ISOLATED FROM PRODUCTION FISH IN BRAZIL

• Grant number: 22/15248-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2023
• End date: September 30, 2025
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Fabiana Pilarski
• Grantee: Daniel de Abreu Reis Ferreira
• Host Institution: Centro de Aquicultura (CAUNESP). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Flavobacterium columnare etiological agent that causes columnariasis in freshwater fish, is a fastidious bacterium, with the morphology of a long gram negative bacillus, the agent has its cosmopolitan distribution affecting the most diverse species of fish, both in natural populations and in fish aquaculture systems, causing countless economic losses for the sector. Due to its high distribution, genetic diversity is observed among isolates from different locations and hosts. Methods based on phylogenetic analyzes allow the classification of isolates into four genetic groups (GGs). GG4 is restricted in its distribution to Asia and Latin America, representing a possible flow history of the tilapia farming chain in its early stages. Therefore, the objective of this study will use the genomic sequencing of the DV001 strain, which showed a remarkable distance of nucleotide similarity, compared to the other isolates of GG4 when analyzing a 1.3Kb fragment of the 16S gene. The strain was isolated by the research group in 2018 and identified as an outbreak-causing agent in commercial tilapia farming in the state of São Paulo, six structural genes will be amplified and phylogenetic analyzes performed by Bayesian inference. This information, combined with computational analysis, based on the sequencing of the genome of the strain, will allow the observation of OGRIs (overall genome related indices), especially ddDNA, G+C and ANI content, incorporated indices for the design of species, in relation to the genomes deposited in GenBank, the values obtained will be used to prospect, if the level of distinction of the strain or of the GG4, requires taxonomic reclassification, using this information together with phenotypic characteristics and comparison with literature data, which will serve to close gaps on the epidemiology of one of the most frequent bacteria in the aquaculture sector, providing a more robust understanding of the genetic status of the species.