Bacterial Gall of Loropetalum chinense caused by Pseudomonas amygdali pv. loropetali pv. nov.

In 2012, stem gall samples on Loropetalum chinense were sent to Florida diagnostic labs from Alabama and Florida nurseries. A fluorescent pseudomonad was consistently isolated from the galls. The organism was originally identified in Alabama based on 16S rRNA sequencing as Pseudomonas savastanoi, which causes a production-limiting disease of olive. The loropetalum strains and reference strains were compared using LOPAT, Biolog, fatty acid analysis, multilocus sequence analysis (MLSA), and pathogenicity tests. The LOPAT tests placed the loropetalum strains within Pseudomonas syringae. Biolog and fatty acid analysis placed the strains in various pathovars of P. syringae and P. savastanoi, respectively. MLSA of a set of housekeeping genes separated the loropetalum strains from the olive knot-inducing strains. Our work indicates there is a need to use more tests than 16S rRNA to accurately diagnose new bacterial diseases. In pathogenicity tests, the loropetalum strains produced galls only on loropetalum, but not on olive, mandevilla, or almond, indicating this strain is not a threat to the olive industry. Based on the pathogenicity assays and molecular tests, loropetalum strains represent a distinct and new pathovar, P. amygdali pv. loropetali pv. nov., for which the strain PDC13-208 (= DSMZ 105780PT) has been designated as the pathotype strain.

Draft genome sequences of Pseudomonas amygdali pv. loropetali pathotype strain DSM 105780 PT, isolated from Florida.

The pathogen that causes stem gall in Loropetalum chinense was first identified in Florida and Alabama in 2018 and named Pseudomonas amygdali pv. loropetali. We report the genome sequence of the pathotype strain of this pathogen, Pseudomonas amygdali pv. loropetali DSM105780 PT.