Curtobacterium uvaldense sp. nov., Falsirhodobacter allii sp. nov., Pseudomonas texasensis sp. nov., Three Novel Species Isolated from Onions in Texas, USA
TL;DR
Three novel species are proposed, Curtobacterium uvaldense sp.
Abstract
Bacterial strains 20TX0008T and 20TX0035T were isolated from the symptomatic onion foliage in 2020, and a bacterial strain 21TX0197T was isolated from the symptomatic onion bulb in 2021. Pathogenicity assays confirmed the two strains isolated from foliage to be non-pathogenic, while the strain 21TX0197T was found to be pathogenic. Phylogenetic analysis using the 16 S rRNA gene revealed the closest resemblance of 20TX0008T, 20TX0035T, and 21TX0197T to the genera Curtobacterium, Falsirhodobacter, and Pseudomonas, respectively. For the respective genus, strains 20TX0008T showed the greatest 16 S rRNA sequence similarity with Curtobacterium caesinilyticum GDMCC 1.2667T (99.7%), 20TX0035T with Falsirhodobacter deserti W402T (99.1%), and 21TX0197T with Pseudomonas uvaldensis 20TX0172T (99.4%). In the phylogenetic trees based on whole genome sequences, all three strains formed a distinct, well-supported branch that separated them from their closely related species within the same genus. The genomic similarity, based on average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), revealed that the novel strains had values below the species delineation thresholds (ANI < 95% and dDDH < 70%), confirming the novelty of all these strains. Based on genomic and phenotypic characteristics, we propose three novel species, Curtobacterium uvaldense sp. nov. (type strain 20TX0008T =LMG 33207T =NCIMB 15480T), Falsirhodobacter allii sp. nov. (type strain 20TX0035T =LMG 33208T =NCIMB 15477T), and Pseudomonas texasensis sp. nov. (type strain 21TX0197T =LMG 33210T =NCIMB 15479T).