Paenibacillus piscarius sp. nov., a novel nitrogen-fixing species isolated from the gut of the armored catfish Parotocinclus maculicauda.

Mariana Barbalho Farias Da Silva,Fernanda Abreu,Ericka Arregue Lemos,Lucy Seldin,Alexandre S Rosado,Renata E Vollú

doi:10.1007/s10482-021-01694-5

Abstract

A Gram-positive, nitrogen-fixing and endospore-forming strain, designated P121T, was isolated from the gut of the armored catfish (Parotocinclus maculicauda) and identified as a member of the genus Paenibacillus based on the sequences of the 16S rRNA encoding gene, rpoB, gyrB and nifH genes and phenotypic analyses. The most closely related species to strain P121T were Paenibacillus rhizoplanae DSM 103993T, Paenibacillus silagei DSM 101953T and Paenibacillus borealis DSM 13188T, with similarity values of 98.9, 98.3 and 97.6%, respectively, based on 16S rRNA gene sequences. Genome sequencing revealed a genome size of 7,513,698bp, DNA G + C content of 53.9mol% and the presence of the structural nitrogenase encoding genes (nifK, nifD and nifH) and of other nif genes necessary for nitrogen fixation. Digital DNA-DNA hybridization (dDDH) experiments and average nucleotide identity (ANI) analyses between strain P121T and the type strains of the closest species demonstrated that the highest values were below the thresholds of 70% dDDH (42.3% with P. borealis) and 95% ANI (84.28% with P. silagei) for bacterial species delineation, indicating that strain P121T represents a distinct species. Its major cellular fatty acid was anteiso-C15:0 (42.4%), and the major isoprenoid quinone was MK-7. Based on physiological, genomic, biochemical and chemotaxonomic characteristics, we propose that strain P121T represents a novel species for which the name Paenibacillus piscarius sp. nov. is proposed (type strain = DSM 25072 = LFB-Fiocruz 1636).

Highlights

The genus Paenibacillus was defined in 1993 after an extensive comparative analysis of 16S RNA gene sequences of 51 species of the genus Bacillus (Ash et al 1991; 1993)
Digital DNA-DNA hybridization experiments and average nucleotide identity (ANI) analyses between strain P121T and the type strains of the closest species demonstrated that the highest values were below the thresholds of 70% dDDH (42.3% with P. borealis) and 95% ANI (84.28% with P. silagei) for bacterial species delineation, indicating that strain P121T represents a distinct species
Genomic, biochemical and chemotaxonomic characteristics, we propose that strain P121T represents a novel species for which the name Paenibacillus piscarius sp. nov. is proposed

Summary

Introduction

The genus Paenibacillus was defined in 1993 after an extensive comparative analysis of 16S RNA gene sequences of 51 species of the genus Bacillus (Ash et al 1991; 1993). In a previous bioprospection study of our group carried out to search for new sources of compounds that may have economic potential (Castro et al 2011), a novel nitrogen-fixing Paenibacillus strain - designated P121 - was isolated from the gut of the armored catfish Parotocinclus maculicauda. Fish belonging to this species are popularly known as Red Fin Dwarf Pleco and are usually found in southern Brazil (Garavello, 1977). The phenotypic, chemotaxonomic and genotypic properties indicate that strain P121T represents a novel species within the genus Paenibacillus, for which the name Paenibacillus piscarius sp. nov. is proposed

Materials And Methods

Results And Discussion

Ethical approval