Curtobacterium uvaldense sp. nov., Falsirhodobacter allii sp. nov., Pseudomonas texasensis sp. nov., Three Novel Species Isolated from Onions in Texas, USA.

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).