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

Abstract

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

“…3 https://github.com/widdowquinn/pyani/blob/master/README_v_0_2_x.md published reports [2,9] place the pathogen closely in two different species: P. amygdali and P. savastanoi, respectively. The highest pairwise ANI of the P. amygdali pv.…”

“…Previously published reports [2, 9] place the pathogen closely in two different species: P. amygdali and P. savastanoi, respectively.…”

“…nov, PDC13-208, isolated from Florida in 2012, was designated as the pathotype strain and deposited in DSM culture collection as DSM 105780 PT . Harmon et al (2018) identified this organism as a pathovar within P. amygdali based on multi-locus sequence analysis (MLSA) [2]. In order to corroborate the MLSA analysis on placement within this species and to understand its relatedness with other members of the Pseudomonas syringae complex, we applied next-generation sequencing to clarify the whole-genome sequence of the pathotype strain.…”

“…loropetali pv. nov, reported to cause stem galls on Loropetalum chinense , was isolated in Florida and Alabama [ 2 ]. L. chinensis is a hardwood species often used as firewood in mountainous part of southern China, whose individual flowers are clustered, covering the branches blooming like fireworks [ 3 ].…”