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Novel species of Frankia, Frankia gtarii sp. nov. and Frankia tisai sp. nov., isolated from a root nodule of Alnus glutinosa

Lookup NU author(s): Dr Imen Nouioui, Emeritus Professor Hans-Peter Klenk, Professor Michael Goodfellow



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2022. The status of four Frankia strains isolated from a root nodule of Alnus glutinosa was established in a polyphasic study. Taxogenomics and phenotypic features show that the isolates belong to the genus Frankia. All four strains form extensively branched substrate mycelia, multilocular sporangia, vesicles, lack aerial hyphae, but contain meso-diaminopimelic acid as the diamino acid of the peptidoglycan, galactose, glucose, mannose, ribose, xylose and traces of rhamnose as cell wall sugars, iso-C16:0 as the predominant fatty acid, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol as the major polar lipids, have comparable genome sizes to other cluster 1, Alnus-infective strains with structural and accessory genes associated with nitrogen fixation. The genome sizes of the isolates range from 7.0 to 7.7 Mbp and the digital DNA G + C contents from 71.3 to 71.5 %. The four sequenced genomes are rich in biosynthetic gene clusters predicted to express for novel specialized metabolites, notably antibiotics. 16S rRNA gene and whole genome sequence analyses show that the isolates fall into two lineages that are closely related to the type strains of Frankia alni and Frankia torreyi. All of these taxa are separated by combinations of phenotypic properties and by digital DNA:DNA hybridization scores which indicate that they belong to different genomic species. Based on these results, it is proposed that isolates Agncl-4T and Agncl-10, and Agncl-8T and Agncl-18, be recognised as Frankia gtarii sp. nov. and Frankia tisai sp. nov. respectively, with isolates Agncl-4T (=DSM 107976T = CECT 9711T) and Agncl-8T (=DSM 107980T = CECT 9715T) as the respective type strains.

Publication metadata

Author(s): Nouioui I, Ghodhbane-Gtari F, Potter G, Klenk H-P, Goodfellow M

Publication type: Article

Publication status: Published

Journal: Systematic and Applied Microbiology

Year: 2023

Volume: 46

Issue: 1

Print publication date: 01/01/2023

Online publication date: 01/11/2022

Acceptance date: 27/10/2022

Date deposited: 28/11/2022

ISSN (print): 0723-2020

ISSN (electronic): 1618-0984

Publisher: Elsevier GmbH


DOI: 10.1016/j.syapm.2022.126377


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