Pseudomonas daroniae sp. nov. and Pseudomonas dryadis sp. nov., isolated from pedunculate oak affected by acute oak decline in the UK

Pseudomonas kirkiae sp. nov., a novel species isolated from oak in the United Kingdom, and phylogenetic considerations of the genera Pseudomonas, Azotobacter and Azomonas

“…Consequently, sequencing of the 16S rRNA and gyrB genes could not assign the Pseudomonas isolates from oak to a species with a high degree of confidence, but phylogenetic analysis revealed they could be divided into three clusters within the genus Pseudomonas suggesting the presence of three novel species. Strains from two of these clusters were recently described as novel species in the Pseudomonas straminea group, namely Pseudomonas daroniae and Pseudomonas dryadis [7]. In this study we use a polyphasic approach, based on genotypic, genomic, phenotypic and chemotaxonomic analyses, to demonstrate that the third of these Pseudomonas clusters constitutes another novel species for which the name Pseudomonas kirkiae sp.…”

“…Over the last ten years, a total of two novel genera, 13 novel species and two novel subspecies have been classified from oak displaying symptoms of decline in the United Kingdom, Spain and the United States of America [1–7]. The majority of bacterial strains have been isolated in the UK from pedunculate oak ( Quercus robur ) exhibiting signs of Acute Oak Decline (AOD), with weeping bleeds, cracked bark plates and necrotic lesions in the underlying tissue [8].…”

“…Cells of the type strain of P. kirkiae sp. nov. were imaged by transmission electron microscopy (TEM) as previously described [7]. Oxidase tests were performed according to the manufacturer’s instructions (bioMérieux), while catalase activity was observed by gas bubble formation following suspension of the bacteria in 3 % w/w hydrogen peroxide.…”

Brenneria goodwinii growth in vitro is improved by competitive interactions with other bacterial species associated with Acute Oak Decline

“…Because of the immense diversity of the oak microbiome, it can't be discounted that other frequently isolated bacteria from oak lesions (ie. Pseudomonas species ( Bueno-Gonzalez et al., 2019 , 2020 ) play a role in the interactions between B. goodwinii, R. victoriana and G. quercinecans . Indeed, further work could include the expansion of the present study with more complex inoculation media and more combinations of bacterial species frequently isolated from AOD symptomatic oak.…”

“…Both biotic and abiotic factors contribute to the decline of symptomatic oak, with a bacterial component recently proven to be the cause of the necrotic lesions that characterise AOD ( Denman et al., 2018 ). In the decade since research into the current episode of AOD in the UK began in earnest, numerous isolation campaigns from symptomatic oak have taken place resulting in an abundance of novel species and even genera that have been validly classified ( Brady et al., 2017 ; Bueno-Gonzalez et al., 2019 , 2020 ). Due to their novel status, our knowledge concerning the biology, genetics and pathogenicity of these bacteria has, until recently, been quite limited.…”